Cleaning method for jet engine

Abstract

To provide a device for foaming a water soluble liquid cleaning agent.SOLUTION: A housing of a device defines an internal flow passage having first flow portion, a second flow portion and a third flow portion, and has a gas inlet, a liquid inlet for a water soluble cleaning agent, and a foam outlet. The first flow portion includes a gas plenum that is configured to receive gas under pressure from the gas inlet and include a plurality of apertures, and the plenum and the interior of the housing form a mixing region that receives liquid from the liquid inlet and receives gas from the apertures. The first portion supplies first foam of the liquid and the gas into the internal flow passage. The second flow portion lets the first foam flow past a foam growth member, which is configured to have a surface area for attachment and merging of cells of the first foam, to form second foam. The third flow portion lets the second foam flow past a foam structuring member, which is configured to reduce the size of at least a part of cells of the second foam, to form third foam supplied to the foam outlet.SELECTED DRAWING: Figure 18A

Description

[Technical field]

[0001] Various embodiments of the present invention relate to apparatus and methods for cleaning devices that include gas paths, including combustion chambers, and in particular to apparatus and methods for cleaning gas turbine engines. [Background technology]

[0002] Turbine engines extract energy to provide power through a wide range of stages. The energy can range from steam to fuel combustion. The extracted power is then utilized for electricity, propulsion, or general power. Turbines work to power helicopters, aircraft, tanks, power plants, ships, specialized vehicles, cities, etc., by converting fluid and gas flows into usable energy. During use, the gas pathways of the device become contaminated by debris and contaminants such as minerals, sand, dust, soot, and carbon. When contaminated, the device's performance deteriorates and maintenance work and cleaning are required.

[0003] Turbines are well known in many forms such as jet engines, industrial turbines or aeroderivative units on land and ships. The internal surfaces of devices such as aircraft or helicopter engines can accumulate contaminant material, thereby restricting the engine's airflow and impairing performance. This can result in increased fuel consumption, shortened engine life and reduced available power.

[0004] The simplest and most cost effective means of maintaining an engine healthy and restoring performance is to properly clean it. Numerous methods are available, such as mist, spray, and steam systems, but all of these cannot reach all the way through or deep into the engine gas path.

[0005] Engine telemetry or diagnostic tools have become routine features for monitoring engine health, but the use of such tools to monitor, induce or quantify improvements from foam engine cleaning has not previously been utilized. Summary of the Invention [Problem to be solved by the invention]

[0006] Various embodiments of the present invention provide novel and unobvious methods and apparatus for cleaning such power equipment. [Means for solving the problem]

[0007] A foam material is introduced into the gas path inlet of the turbine equipment while off-line. The foam coats and contacts the interior surfaces to scrape, remove and carry away contaminant material from the equipment.

[0008] One aspect of the invention relates to an apparatus for foaming a cleaning agent. Some embodiments include a housing defining an internal flow path having a first flow section, a second flow section, and a third flow section, a gas inlet, a liquid inlet for the cleaning agent, and a foam outlet. The first flow section includes a gas plenum adapted and configured to receive gas under pressure from the gas inlet and include a plurality of openings, the gas plenum and the interior of the housing forming a mixing region that provides a first foam of liquid and gas. The second flow section receives the first foam and flows the first foam through a foam growth matrix adapted and configured to have a surface area for cell attachment and fusion. The third flow section flows the second foam through a foam structuring member downstream of the first or second section adapted and configured to reduce the size of at least a portion of the cells. It is understood that still other embodiments of the invention contemplate a housing having only the first section, or only the first and second sections, or only the first and third sections, in various other nucleation devices.

[0009] Another aspect of the invention relates to a method for foaming a liquid cleaning agent. Some embodiments include mixing a liquid cleaning agent and a pressurized gas to form a first foam. Other embodiments include flowing the first foam through a member or matrix to form a second foam, increasing the size of the cells of the first foam. Still other embodiments include flowing the second foam through a structure such as a mesh or a plate with one or more apertures to form a third foam, decreasing the size of the cells of the second foam.

[0010] Yet another aspect of the invention relates to a system for providing air-foamed liquid cleaning agent. Another embodiment includes an air pump or pressurized gas reservoir providing air or gas at a pressure greater than ambient pressure, and a liquid pump providing liquid under pressure. Yet another embodiment includes a nucleation device receiving pressurized air, a liquid inlet receiving pressurized liquid, and a foam outlet, the nucleation device turbulently mixing the pressurized air and liquid to form foam. Yet another embodiment includes a nozzle receiving foam through a foam conduit, the internal passages of the nozzle and the conduit adapted and configured to not increase turbulence of the foam, and the nozzle adapted and configured to deliver a low velocity stream of foam.

[0011] Yet another aspect relates to a method of delivering an air-foamed liquid cleaning agent to an inlet of a jet engine installed in an aircraft. Some embodiments include providing a pressurized source of liquid cleaning agent, an air pump, a turbulent mixing chamber, and a non-atomizing delivery opening. Other embodiments include mixing pressurized air with pressurized liquid in the mixing chamber to form a foam supply. Still other embodiments include directing the foam supply into the installed engine through the inlet or from the opening through various tubes attached to the engine.

[0012] Yet another aspect of the invention relates to an apparatus for foaming an aqueous liquid cleaning agent. Some embodiments include a means for mixing a pressurized gas with a flowing aqueous liquid to form a foam. Other embodiments include a means for growing the size of the foam cells and a means for reducing the size of the grown cells.

[0013] In various embodiments of the present invention, the effluent after a cleaning operation is collected and evaluated. This evaluation may include on-site analysis of the contents of the effluent, including whether specific metals or compounds are present in the effluent. Based on the results of this evaluation, a decision is made as to whether further cleaning is appropriate.

[0014] Yet another embodiment of the invention relates to a method for evaluating the effectiveness of a cleaning operation, the evaluation being used to evaluate the terms of a contract. As an example, the contract may relate to the terms of an engine warranty provided by an engine manufacturer to an aircraft operator or owner. In yet another embodiment, the evaluation can be used to evaluate the terms of a contract relating to the engine cleaning operation itself. In yet another embodiment, the evaluation of the cleaning effectiveness on an engine can be used to evaluate the engine against establishing FFA maintenance criteria for the engine.

[0015] In one embodiment, the evaluation method includes operating the engine in a commercial flight environment for about two months or more. In some embodiments, it is anticipated that this operation may include multiple flights per day and use of the aircraft for up to seven days per month. The method further includes operating the used engine and establishing a baseline characteristic. In some embodiments, the baseline characteristic is a fuel consumption rate at a particular thrust level, engine pressure ratio, or rotor speed. In some alternatives, the method includes correcting this baseline data for environmental atmospheric characteristics. In yet another embodiment, the baseline parameter is the elapsed time between starting the engine from 0 rpm to idle speed. In yet another embodiment, the baseline evaluation of the used engine includes evaluating the engine start time in the following manner: performing a first start of the engine, shutting off the engine, running the engine on the starter (without burning fuel) for a predetermined period of time, and after running, performing a second engine start and using the second engine start time as the baseline start time.

[0016] The method further includes cleaning the engine. This cleaning of the engine may include one or more successive cleaning cycles. After the engine is cleaned, the baseline test method is repeated. This second test result (of the cleaned engine) is compared to the baseline test result (of the used engine as received) and the change in engine characteristics is evaluated against contractual guarantees. As one example, the operator of the cleaning equipment may have offered contractual terms to the aircraft owner or operator regarding the improvement made by the cleaning method. Additionally, in another example, the delta improvement provided by the cleaning method (or alternatively, the test results of the cleaned engine considered by itself) may be compared to contractual guarantees between the manufacturer of the engine (or the facility that performed the previous overhaul of the engine or the licensee of the engine) to evaluate whether the cleaned engine meets these contractual terms.

[0017] In yet another embodiment, there is a cleaning method performed on an engine where a baseline test is used, the engine is cleaned and the baseline test is performed twice. The comparison of the baseline test to the clean engine test can be used for any reason.

[0018] In yet another embodiment, the cleaning method includes operating the engine in a cleaning cycle, which (or a different cleaning cycle) is then applied to the engine. Preferably, the cleaning agent is provided to the engine at a relatively low rotational speed, preferably less than about half the normal idling speed of the engine.

[0019] In yet another embodiment, such as those engines supported substantially vertically, a cleaning agent can be applied to the engine when it is stationary (i.e., at 0 rpm). After a sufficient amount of agent has been applied, the engine can then be rotated at any speed, after which the cleaning agent can be washed off.

[0020] Yet another embodiment of the present invention relates to a method for cleaning an engine, including manipulating the temperature of the cleaning agent and / or the temperature of the engine being cleaned. In one embodiment, the cleaning system includes a heater adapted and configured to heat the cleaning agent prior to forming the cleaning foam. In yet another embodiment, the method includes a heater for heating air used to form the foam with the cleaning liquid. In yet another embodiment, the cleaning device includes one or more air blowers (similar to "alligator" space heaters used on construction sites) having a source of heated ambient air. These hot air blowers can be positioned at the inlet of the engine, and the engine can be free-running (i.e., running on a starter without burning fuel) for a predetermined period of time (which can be based on ambient conditions) or free-running until a thermocouple or other temperature measuring device in a hot area of ​​the engine reaches a predetermined temperature. In yet another embodiment, the temperature of the engine prior to the introduction of the cleaning foam can be increased by starting the engine and running the engine at an idling condition for a predetermined period of time, after which the engine can be shut off prior to the introduction of the cleaning foam. In yet another embodiment, the engine can be allowed to run after shutting down from idle and prior to introduction of the agent to further achieve consistent baseline temperature conditions prior to introduction of the foam. Still other embodiments of the present invention contemplate any combination of pre-heated liquid agent, pre-heated compressed air used for foaming, an externally heated engine, and an engine "warmed" by one or more recent periods of operation.

[0021] In yet another embodiment of the present invention, the cleaning foam can be heated by providing a heating element within the device used to mix and form the cleaning foam.

[0022] It will be appreciated that the various devices and methods described in this Summary, as well as elsewhere in this application, can be expressed in many different combinations and sub-combinations, and all such useful, novel, and inventive combinations and sub-combinations are contemplated herein, with the recognition that explicit representation of each of these combinations is unnecessary.

[0023] Some of the figures shown herein may include dimensions. Additionally, some of the figures shown herein may be made from scaled drawings or scalable photographs. It is understood that such dimensions or relative scales within the figures are present for illustrative purposes and are not to be construed as limiting. [Brief description of the drawings]

[0024] [Figure 1] Schematic diagram of a gas turbine engine. [Diagram 2] 1 is a schematic diagram of a cleaning device according to one embodiment of the present invention. [Figure 3A] Photograph of part of the apparatus in Figure 2. [Figure 3B] Photograph of a portion of the apparatus of FIG. 2 showing the provision of foam within the inlet of an installed engine. [Figure 3C] Photograph of a nozzle according to one embodiment of the present invention in front of an engine inlet. [Figure 3D] Photograph of a nozzle according to another embodiment of the present invention in front of the engine inlet. [Figure 4] Photograph of a foam structure according to one embodiment of the present invention. [Figure 6] Photographs of a portion of an engine's exhaust structure before and after being cleaned with one embodiment of the present invention. [Figure 7] 4 is a graph of the improvement in engine start time for an engine cleaned with one embodiment of the present invention. [Figure 8] Photograph of an engine being washed on an engine test stand according to one embodiment of the present invention. [Figure 9] Photograph of a portion of the apparatus in Figure 8. [Figure 10] 4 is a graph of parameter improvements for an engine cleaned according to one embodiment of the present invention. [Figure 11] 4 is a graph of parameter improvements for an engine cleaned according to one embodiment of the present invention. [Figure 12A] 1 is a schematic diagram of a cleaning system according to one embodiment of the present invention. [Figure 12B] Schematic diagram of a cleaning system according to another embodiment of the present invention. [Figure 13A] Photograph of one embodiment of a portion of the device of FIG. 12A. [Figure 13B] Photograph of one embodiment of a portion of the device of FIG. 12A. [Figure 13C] Photograph of one embodiment of a portion of the device of FIG. 12A. [Figure 14A] An enlarged photograph of a portion of the device in Figure 13. [Figure 14B] An enlarged photograph of a portion of the device in Figure 13. [Figure 14C] An enlarged photograph of a portion of the device in Figure 13. [Figure 14D] An enlarged photograph of a portion of the device in Figure 13. [Figure 15A] Photograph of the inside of the cabinet in Figure 13. [Figure 15B] Photograph of the inside of the cabinet in Figure 13. [Figure 15C] Photograph of the inside of the cabinet in Figure 13. [Figure 15D] Photograph of the inside of the cabinet in Figure 13. [Figure 16A] Photograph of the components shown in FIG. 15B. [Figure 16B] Photograph of the components shown in FIG. 15B. [Figure 16C] Photograph of the components shown in FIG. 15B. [Figure 16D] Photograph of the components shown in FIG. 15B. [Figure 16E] Photograph of the components shown in FIG. 15B. [Figure 16F] Photograph of the components shown in FIG. 15B. [Figure 18A]2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18B] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18C] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18D] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18E] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18F] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18G] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18H] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18I] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18J] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18K] 2 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18L] 12A-12C are cutaway schematic views of nucleation chambers according to various embodiments of the present invention. FIG. 12A shows a schematic view of a nucleation chamber according to one embodiment of the present invention, with cross-section view AA of nucleation chamber 1260. [Figure 18M] 18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; FIG. 18C is an end view of nucleation chamber 1260 as viewed from 18M-18M in FIG. 18L; [Figure 18N] 18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged view of a portion of the apparatus of FIG. 18L. [Figure 18O]18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged schematic view of a portion of the apparatus of FIG. 18L. [Figure 18P] 18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged schematic view of a portion of the apparatus of FIG. 18L. [Figure 18Q] 18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged schematic view of a portion of the apparatus of FIG. 18L. [Figure 18R] 18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged schematic view of a portion of the apparatus of FIG. 18L. [Figure 19A] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 19B] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 19C] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 19D] CAD drawing of an aircraft with the engine installed and being foam washed. [Figure 19E] CAD drawings of multiple effluent collectors according to various embodiments of the present invention. [Figure 2-1A] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 2-1B] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 2-2] 1 is a pictorial representation of an aircraft engine being cleaned by a system according to one embodiment of the present invention and by one embodiment of an effluent capture device. [Figure 2-3]1 is a pictorial representation of an aircraft engine being cleaned by a system according to one embodiment of the present invention and by one embodiment of an effluent capture system according to one aircraft scenario; [Figure 2-4] 1 is a pictorial representation of an aircraft engine with a variable foam effluent capture system being cleaned by a system according to one embodiment of the present invention; [Figure 2-5] 1 is a schematic and photo illustration of an aircraft engine being cleaned by a system according to one embodiment of the present invention; [Figure 2-7] Schematic diagram of the cleaning process according to the present invention. [Figure 2-8A] 1 is a schematic diagram of an engine illustrating a foam injection system according to one embodiment of the present invention. [Figure 2-8B] 1 is a schematic diagram of an engine illustrating a foam injection system according to one embodiment of the present invention. [Figure 2-9A] 1 is a schematic diagram of an internal cutaway of an engine showing a foam connection system according to one embodiment of the present invention. [Figure 2-9B] 1 is a cutaway schematic of an engine with internal and external components showing a foam connection system according to one embodiment of the present invention. [Figure 2-10] 1 is a graph of engine cleaning cycle prescription according to one embodiment / method of the present invention. [Figure 2-11] 1 is a graph of one method for engine monitoring and quantifying benefits according to one embodiment / method of the present invention. [Figure 2-12A] Photograph of an effluent collector according to one embodiment of the present invention. [Figure 2-12B] FIG. 12B is a front view of the device of FIGS. 2 to 12A looking toward the rear. [Figure 2-12C] FIG. 12B is a front-facing rear view of the device of FIGS. 2 through 12A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] (Element symbol) Below is a list of element symbols and at least one name used to describe the element. It is understood that none of the embodiments disclosed herein are limited to these names, and that these symbols may further include other terms that would be understood by one of ordinary skill in the art upon reading and studying this disclosure as a whole. [Table 1]

[0026] For the purpose of promoting an understanding of the principles of the invention, reference will be made to the illustrated embodiments and specific language will be used to describe the same. No limitation of the scope of the invention is intended thereby, however, and it will be understood that such substitutions and further modifications in the illustrated devices, and such further applications of the principles of the invention as exemplified herein, are contemplated as would normally occur to one skilled in the art to which the invention pertains. Although at least one embodiment of the invention has been described and shown, the present application may show and / or describe other embodiments of the invention.

[0027] The term "the present invention" refers to a group of embodiments of the present invention, and it is understood that no one embodiment includes an apparatus, process, or composition that must be included in all embodiments unless expressly stated otherwise. Furthermore, although there is a discussion of "advantages" provided by some embodiments of the present invention, it is understood that other embodiments may not exhibit these advantages, or may even exhibit different advantages. Any advantages discussed herein are not to be construed as limitations on anything in the claims. The use of language indicating preferences, such as "preferably," refers to configurations and aspects that are present in at least one embodiment, but are optional in some embodiments.

[0028] The use of N-series prefixes in the designation (NXX.XX) refers to elements that are the same as the element without the prefix (XX.XX), except as shown and described. As one example, element 1020.1 is the same as element 20.1, except as the different configurations of element 1020.1 shown and described. Furthermore, common elements and common configurations of related elements may be depicted in the same manner with different numbers and / or use the same symbols in different figures. Thus, it is not necessary to describe the configurations of 1020.1 and 20.1 that are the same, since these common configurations will be apparent to those of ordinary skill in the relevant art. Furthermore, it is understood that the configurations 1020.1 and 20.1 may be backward compatible such that the configuration (NXX.XX) may include configurations that are compatible with various other embodiments (MXX.XX), as will be understood by those of ordinary skill in the art. This description convention also applies to the use of the dash ('), double dash ("), and triple dash ("') suffix element numbers. Therefore, it is not necessary to describe the features of 20.1, 20.1', 20.1", and 20.1"' that are the same, since their common features will be apparent to one of ordinary skill in the relevant art.

[0029] Although various specific quantities (such as spatial dimensions, temperature, pressure, time, force, resistance, current, voltage, concentration, wavelength, frequency, heat transfer coefficients, dimensionless parameters, etc.) are described herein, such specific quantities are presented by way of example only and, unless expressly noted otherwise, are approximations and should be considered as if each quantity were preceded by the word "about." Furthermore, in any discussion of specific compositions, the description is by way of example only and is not intended to limit the application of that composition to other species or other compositions unrelated to the cited composition.

[0030] Below follow paragraphs describing particular embodiments of the invention. In these following paragraphs, some element numbers are prefixed with an "X" to indicate that the term refers to any of the similar structures shown in the figures or described in the text.

[0031] Shown and described herein in conjunction with various embodiments of the invention is a discussion of one or more tests that have been performed. It is understood that such examples are exemplary only and are not to be construed as limitations on any embodiment of the invention. It is further understood that embodiments of the invention are not necessarily limited to or explained by the mathematical analyses presented herein.

[0032] Various references may be made to one or more processes, algorithms, methods of operation, or logic, which are accompanied by diagrams illustrating the organization of such in a particular sequence, it being understood that the ordering of such sequences is by way of example only and is not intended to limit any embodiment of the invention.

[0033] Various references may be made to one or more methods of manufacture. These are by way of example only, and it will be understood that various embodiments of the present invention may be fabricated in a wide variety of ways, such as, by way of example only, casting, centering, welding, electro-discharge machining, milling, etc. Additionally, various other embodiments may be fabricated by any of a variety of additive manufacturing methods, some of which are referred to as 3D printing.

[0034] This document may use different words to describe the same symbol or to refer to a symbol within a unique group of features (NXX.XX). It is understood that such usage is not intended to provide a redefinition of any language herein. It is understood that such words may be considered in various linguistic ways, and that such ways are not necessarily additive or exclusive.

[0035] Shown and described herein are one or more functional relationships among variables. Although a specific nomenclature of variables can be provided, some relationships may include variables that are recognized by those skilled in the art for their meaning. For example, "t" can represent temperature or time, as is readily apparent from its usage. However, it is further recognized that such functional relationships can be expressed in various equivalents using standard techniques of mathematical analysis (e.g., the relationship F=ma is equivalent to the relationship F / a=m). Furthermore, in embodiments where the functional relationships are implemented in an algorithm or computer software, it is understood that the algorithmized variables can correspond to the variables shown herein, where the correspondence includes scaling factors, control system gains, noise filters, or the like.

[0036] A wide variety of methods have been used to clean gas turbine engines. Some users utilize water sprayed into the engine inlet, others utilize cleaning fluids sprayed into the engine inlet, and still others provide a solid abrasive material, such as walnut shells, to the engine inlet.

[0037] These methods have achieved varying degrees of success and have also caused varying degrees of problems. For example, some cleaning agents that are strong enough to clean the hot zones of an engine and are chemically acceptable on the hot zone materials are chemically unacceptable on the materials used in the cold zones of the engine. Water washing is gentle enough to be used on any material of the engine, but is not effective at removing particularly difficult deposits, and may leave silica deposits in some stages of the compressor. Several water-soluble cleaning agents are recognized in MIL-PRF-85704C, but many users of these cleaning agents consider them marginally successful in restoring performance to engine operating parameters, and still others point out that cleaning alone with these MIL cleaning agents may actually degrade some operating parameters.

[0038] Thus, many aircraft operators are skeptical of some liquid cleaning methods, i.e., the claims made regarding how effective the liquid is in restoring performance to the engine. The costs of liquid washing include the price of liquid washing the engine and the time the aircraft is taken out of operation. Often, the benefits of liquid washing do not outweigh the costs incurred or provide only marginal commercial benefits.

[0039] Various embodiments of the present invention demonstrate the significant commercial benefits that can be obtained by foam washing of gas turbine engines. As shown herein, foam cleaning of engines can provide significant improvements in operating parameters, including improvements that cannot be obtained with liquid washing. The reasons for the significant improvements realized by foam washing are not fully understood. Back to back engine tests have been performed on the same specific engine, in which an atomized liquid is introduced at the inlet, and then a foam of the same liquid is introduced at the inlet. In all cases, the liquid (or foam) is observed in the engine exhaust area, indicating that the liquid (or foam) appears to wet the entire gas path. Nevertheless, the use of foam liquid provides significant improvements over any improvements of liquid washing in important operating parameters such as engine start time, specific fuel consumption, and turbine temperature required to achieve a particular power output.

[0040] Some embodiments of the present invention relate to systems for generating foam from water-soluble cleaning agents. It has been found that differences exist regarding the apparatus and methods for forming acceptable foam with water-soluble or non-water-soluble agents. Various embodiments of the present invention relate to systems that include a nucleation chamber to which pressurized liquid and further pressurized air are provided.

[0041] It has been found that injecting this foam into the engine inlet with a conventional spray nozzle can reduce the cleaning effectiveness of the foam. Additionally, any piping, tubing or hose that delivers the foam from the nucleation chamber to the nozzle should be generally smooth and substantially free of turbulent flow-generating features in the flow path (such as delivery nozzles with areas with sharp turns, sudden reductions in the flow area of ​​the foam flow path, or excessive convergence, such as convergence that increases the velocity of the foam).

[0042] In various embodiments of the present invention, it is useful to provide a flow path for the generated foam that maintains the foam in a higher energy state and does not dissipate that energy before delivery. FIG. 3B shows foam being delivered by one embodiment of the present invention. It can be seen that the nozzle 30 provides a stream of foam that is of approximately the same diameter. Little or no convergence is evident in the photograph of FIG. 3B, and there is no deviation in the flow stream. Furthermore, the ripples or "lumps" in the flow stream of foam are indicative of a slow delivery system, where the disturbance imparted to the foam stream when it hits the spinner clearly travels upstream towards the nozzle. It can be seen that the amplitude of the "lumps" in the foam flow path is greatest near where the spinner hits the foam, and decreases in magnitude as it moves towards the outlet nozzle 30. The foam outlet nozzle 30 is of approximately constant diameter and preferably at a velocity of less than about 15 feet per second.

[0043] Various embodiments of the present invention are also aided by the introduction of gas (including air, nitrogen, carbon dioxide, or any other gas) under pressure into the flow of cleaning liquid. Preferably, the air is pressurized to greater than about 5 psig and less than about 120 psig and is supplied by a pump or pressurized reservoir. While some embodiments of the present invention include the use of an airflow evacuation device that may entrain ambient air, yet other embodiments using pressurized air have been found to provide improved results.

[0044] Yet another embodiment of the present invention relates to the commercial use of foam cleaning in aircraft engines. As previously discussed, the mechanism by which foamed cleaning agents provide superior results over non-foamed cleaning agents is not well understood at this time. Conversely, many experts in the field of jet engine maintenance initially believe that foamed cleaning agents provide the same disappointing results as those provided by non-foamed cleaning agents. Thus, as the use of foam cleaning agents becomes better understood, the effect of improved foam cleaning on the financial considerations of supporting a fleet of engines will become better understood. Some of these improvements are readily apparent, such as improvements in operating temperatures, specific fuel consumption, and start times, as shown by the tests documented herein. Still other effects from the use of foam cleaning agents can further impact the design of other life-limited components within the engine.

[0045] For example, engines are currently designed with parts that have a limited life (such as hours of use, time temperature, number of engine cycles, or other basis), and inspection of these components can be scheduled at the same time as liquid washing of the engine. However, because foam washing restores used engines to a better performance level than liquid washing, the use of foam washing can usually increase the amount of time that the engine can be installed on an aircraft. However, the increase in time between foam washings (increased compared to the interval between liquid washings) can be long enough that the foam washing is not done at the same time as inspection of the limited life parts. Under these conditions, it may be financially worthwhile to design the limited life parts for a slightly longer cycle. The increase in cost of the limited life components for the longer life can be more than offset by the increase in the amount of time that a foam-cleaned engine can remain on the wing.

[0046] In such embodiments, improved cleaning resulting at least in part from foam cleaning can result in a paradigm change in engine washing, inspection, and maintenance intervals. In some embodiments, the effect of foam cleaning on engine performance parameters (such as start-up time, temperature at full rated power, specific fuel consumption, carbon emissions, nitrogen oxide emissions, normal operating speeds of the engine in cruise and takeoff, etc.) can be quantified. This quantification can be done for a family of engines, but in some cases can be applicable across different families. When a particular engine in the family is operated on an aircraft, the aircraft operator notes any changes in operating parameters that can be correlated to improvements obtained by foam cleaning for that particular engine. This information obtained by the aircraft operator is passed to the engine owner (which can be the US government, the engine manufacturer, or an engine leasing company), who determines when to schedule foam cleaning for that particular engine.

[0047] Various embodiments of the foam cleaning methods and apparatus described herein have been found through experimentation to be more effective at removing contaminants from used engines than spray cleaning with a liquid cleaning agent. In some cases, the effluent collected in the turbine after foam cleaning was compared to the effluent collected in the turbine after liquid cleaning, where the liquid cleaning preceded the foam cleaning. In these cases, the foam effluent was found to have significant amounts of dirt and deposits contained therein that were not removed by the liquid cleaning.

[0048] In some engine series, the use of foam cleaning is believed to provide improvements in combustor liner cleanliness. Combustor liners are well known to contain an intricate arrangement of cooling holes that are designed not only to maintain a safe temperature for the liner itself, but also to further reduce gas path temperatures, thereby inhibiting the formation of nitrogen oxides. Various embodiments of the present invention are expected to demonstrate reduced emissions of nitrogen oxides in cleaned engines.

[0049] 1-4 depict various views of a washing or cleaning system 20 according to one embodiment of the present invention. Shown and described is a washing system 20 applied to cleaning a gas turbine engine, although it is understood that various embodiments of the present invention contemplate cleaning any object.

[0050] 1 and 2 diagrammatically represent a system 20 used to clean a jet engine 10. The engine 10 includes a cold section that typically includes an inlet 11, a fan 12, and one or more compressors 13. Compressed air is provided to a hot section of the engine 10 that includes a combustor 14, one or more turbines 15, and an exhaust system 16 that illustratively includes simple convergent nozzles, noise reducing nozzles (as seen in FIG. 6), and cooled nozzles (such as those used with post-combustion engines and including convergent and divergent sections).

[0051] 2 shows a schematic of a system 20 used to clean engine 10 with foam. System 20 typically includes a gas source 26, a water source 24, and a cleaning agent source 22, all of which are provided to a foaming system 40. Foaming system 40 receives these input components and provides an output of foam 28 to nozzle 30, which provides the foam to inlet 11 of engine 10. However, still other embodiments contemplate positioning nozzle 30 such that the foam is first provided to compressor region 13, or in some embodiments, to still other components of engine 10. System 20 preferably includes an effluent collector 32 located aft of exhaust 16 of engine 10, thereby collecting therein spent foam, agent, water, and particulate matter removed from engine 10.

[0052] 3A and 3B depict the cleaning system 20 in operation. In one embodiment, the foaming system 40 is disposed within a cabinet 42. The cabinet 42 preferably contains the various equipment used to form the foam 28, including a nucleation chamber, a pump, and various valves and piping (as shown and described with reference to FIG. 15). The cabinet 42 preferably contains various flow meters or peristaltic pumps 44, pressure gauges 46, and pressure regulators 48 (as described with reference to FIGS. 12-14).

[0053] Figure 3B is a photograph of nozzle 30 injecting foam 28 into engine inlet 11. Figure 4 is a close-up photograph of foam 28 according to one embodiment of the present invention.

[0054] 3C and 3D show a nozzle 30 in front of the inlet 10 according to another embodiment of the invention. It can be seen that some embodiments utilize pairs of nozzles that deliver foam to the inlet from approximately the same location and space, except on either side of the engine centerline. Typically, the nozzles in some embodiments have non-atomizing nozzles that provide a stream of foam to ambient conditions. As can be seen in FIGS. 3C and 3D, the cross-sectional area of ​​the nozzle arrangement 30 increases generally from the integral central delivery tube to the pair of side-by-side outlet nozzles, each of which is approximately the same cross-sectional area. Thus, the cross-sectional area as a function of length along the flow path of the arrangement 30 is relatively constant in the central region, but then increases as the central region splits into two side-by-side nozzles.

[0055] Figures 6-11 relate to various tests performed with various embodiments of the present invention. Figure 6 provides an illustration of a corrugated ambient noise suppression exhaust nozzle 16 both after cleaning with existing procedures and after cleaning performed with an embodiment of the present invention. Comparing the left and right photographs, it can be seen that after cleaning performed with one embodiment of the present invention (right photograph), the exhaust nozzle 16 has been cleaned beyond the level of cleanliness previously achieved after a standard cleaning procedure (left photograph).

[0056] 7 provides a pictorial illustration of the improvement in engine start-up time, including results after a standard wash and after a wash according to one embodiment of the present invention. It can be seen that the standard wash reduced the start-up time of the particular engine by only 3 seconds, from 69 seconds to 66 seconds. However, a subsequent wash of the same engine with the wash system of the present invention resulted in a further reduction in start-up time of about 9 seconds, thus demonstrating that a cleaning method according to one embodiment of the present invention can improve the flow dynamics of the engine gas path beyond the improvements achieved by standard wash (such as a method in which a spray of atomized cleaning fluid is provided into the engine inlet).

[0057] Figures 8-11 show tests performed on a helicopter engine and the test results. Figures 8 and 9 show the engine 10 being cleaned with exit foam 28 exiting the dual exhaust nozzle 16. Figure 10 shows the results of several start-up tests performed on the helicopter engine. It can be seen that the start-up time of the used engine was reduced by about 5 percent using existing cleaning technology. However, cleaning that same engine with a cleaning system according to one embodiment of the present invention still provided additional gains and a reduction in start-up time of over 22 percent (compared to the original used engine).

[0058] Figure 11 illustrates the improvement in exhaust gas temperature margin of a helicopter engine operating at full speed before and after cleaning. It can be seen that the use of existing cleaning systems on the engine did not result in a measurable improvement in EGT margin. However, that same engine showed an increase in EGT margin (i.e., ability to run coolers) of over 30°C after being cleaned using a system and method according to one embodiment of the present invention.

[0059] Figures 12A and 12B show in schematic form cleaning systems 20 and 120 according to various embodiments of the present invention. Many of the components shown generally in Figures 12A and 12B (including pressure gauges, flow meters, pressure reducing valves, pumps, check valves, nucleation chambers, and other valves and piping) are preferably housed within a cabinet 42, which can be seen in Figures 13, 14, and 15.

[0060] Figures 13A, 13B, and 13C are photographs of the exterior of cabinet 42 of foaming system 40 according to one embodiment of the present invention. Various inlets, shutoff valves, flow meters, pressure gauges, and connections are visible in these photographs. Additionally, the depictions of Figures 13, 14, and 15 are of the same flow system 40, and the various interconnections visible in Figure 15 can originate from the cabinet exterior shown in Figures 13 and 14.

[0061] Figure 14 is an enlarged view of a portion of the flow cabinet 42 of Figure 13. Figure 14B shows that in one embodiment, chemical A is preferably provided at about 0.0265 cubic meters (about 7 gallons) per hour and chemical B is provided at about 0.0719 cubic meters (about 19 gallons) per hour. Figure 14C shows that the air flow entering the nucleation chamber was between about 0.368 cubic meters per minute and about 0.396 cubic meters (about 13 to 14 cubic feet) per minute, and the water flow (after the pump) used to form the foam was between about 0.0265 cubic meters and about 0.0303 cubic meters (about 7 to about 8 gallons) per minute. Figure 14D shows that the water flow measured before the pump is about 0.0265 cubic meters (about 7 gallons) per minute. The pressure gauge in FIG. 14D shows the working pressure of air, water, and foam at approximately 18-20 psig. These specific settings are illustrative only and are not to be construed as limiting. Additionally, these settings were utilized with the specific example flowing Zok27 Agent A and / or Turco5884 Agent B. Similarly, any combination of approved products or base components (i.e., kerosene, isopropyl alcohol, petroleum solvents) may be utilized as per the engine manual. For reference, qualified product listings or approvals are associated with the FAA or by Naval Air Systems Command approval. Such gas path approval reports are dictated by the MIL-PRF-85704 reference followed by the industry.

[0062] FIG. 15 shows the components and piping housed within cabinet 42 and corresponds to FIGS.

[0063] 16 and 18 show various embodiments of the nucleation chamber X60 according to various embodiments of the present invention. Many of these embodiments include a housing X61 that includes an inlet X62 for a gas, an inlet X63 for one or more liquids, and an outlet X64 that provides a foam output 28 to the nozzle X30. In some embodiments, a gas chamber X66 receives gas under pressure from the inlet X62. The gas chamber X66 is preferably enclosed within the housing X61, and is positioned such that a portion of the gas chamber X66 contacts the fluid from the inlet X63 within the housing X61. Some embodiments include a gas chamber X66 that includes one or more openings or other features X70 that provide fluid communication from the internal passage of the chamber X66 and the fluid within the housing X61.

[0064] The introduction of gas through opening X70 is adapted and configured to form a foam with the cleaning liquid in nucleation zone X65. Preferably, the foam is formed by nucleation of a pre-qualified aerated agent using appropriate arrangement of high velocity air jets, diffuser regions, growth spikes, and / or centrifugal shearing of the agent, any of which can be used to form a foam that is a higher energy, short-lived state of the more stable non-foaming liquid agent. The resulting foam is provided to outlet X64 for introduction into the inlet of the device to be cleaned.

[0065] In some embodiments, chamber X60 further includes a cell growth region X74 where materials or devices are present that promote the fusion of small foam cells into larger foam cells. In yet other embodiments, nucleation chamber X60 can include a cell structuring region X78 that includes materials or devices to improve the uniformity of the foam material. Yet another embodiment of X60 includes a laminar flow region X82 in which the foamed material 28 is made less turbulent to increase the longevity of the foam cells and thus increase the number of foam cells delivered to the inlet 11 of the product 10 being cleaned.

[0066] Some nucleation chambers X60 include a nucleation zone, a growth region, and a structured region arranged in series within a foam flow path. In yet other embodiments, the zones and regions are arranged coaxially with the foam initially forming proximal to the centerline of the flow path. In yet other embodiments, the zones and regions are arranged coaxially with the foam forming at the periphery of the flow path and the cells growing and becoming progressively structured toward the center of the flow path.

[0067] Some of the nucleation chambers X60 described herein include a nucleation zone, a growth region, and a structured region arranged within a single plenum. However, it is understood that other embodiments contemplate modular arrangements for the nucleation chambers. For example, the nucleation zone can be a separate component bolted to the structured zone or the laminar flow zone. For example, the various regions can be attached to each other by flanges and fasteners, threaded fittings, or the like. Additionally, the system X20 is described herein as including a single nucleation chamber. However, it is understood that the cleaning system can include multiple nucleation chambers. As one example, multiple chambers can be fed from a manifold that provides liquid and gas. This parallel flow arrangement can provide similarly diversified foam output together to a single nozzle X28 or to multiple nozzles arranged in a pattern to best match the engine inlet geometry.

[0068] The various cleaning systems X20 discussed herein can include a mixture of liquids (such as water, chemical A, and chemical B) provided to an inlet of a nucleation chamber into which a gas is injected to form bubbles from the mixture of liquids. However, the invention is not so limited and further includes those embodiments in which the liquids can be bubbled separately. For example, a cleaning system according to another embodiment of the invention can include a first nucleation chamber for chemical A and a second nucleation chamber for a mixture of chemical B and water. The resulting two bubbles can then be provided to a single nozzle X28 or can be provided to separate nozzles X28.

[0069] The various descriptions that follow relate to a variety of embodiments of the nucleation chamber X60 incorporating numerous differences and numerous similarities. It will be understood that each of these is presented by way of example only and is not intended to limit the broad ideas expressed herein. As yet another example, the present invention contemplates an embodiment in which a liquid product is provided at an inlet X63 and flows within a flow path surrounded by a centrifugal gas chamber X66. In such an embodiment, the gas chamber X66 defines an annular flow space and provides gas under pressure from the inlet X62 to the liquid product flowing within the annulus.

[0070] 18A and 18B show a nucleation chamber 60 according to one embodiment of the present invention. A housing 61 includes a gas inlet 62, a liquid inlet 63, and a foam outlet 64, with a foam forming passageway disposed between the inlets and outlets. Contained within the housing 61 is a generally cylindrically shaped gas tube 66 which receives gas under pressure from the inlet 62. Although the gas chamber 66 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into the liquid stream such that bubbles result.

[0071] The gas tube 66 is generally coaxially disposed within the housing 61 (although a coaxial arrangement is not required) such that liquid from the inlet 63 flows generally around the exterior surface of the tube 66. The tube 66 preferably includes a plurality of apertures 70 adapted and configured to allow gas from within the tube 66 to flow generally to a bubble-forming passageway within the housing 61. As shown in FIG. 18A, the apertures 70 are disposed generally along the length of the tube 66, preferably around the circumference of the tube 66. However, still other embodiments of the present invention contemplate the apertures 70 having locations limited to certain selected portions of the tube 66, such as toward the inlet, toward the outlet, approximately in the center, or any combination thereof.

[0072] By way of example, nucleation jets 70 are adapted and configured to have a total flow area approximately equal to or less than the cross-sectional flow area of ​​housing 61. By way of example, jets 70 have a hole diameter of about 1 / 8 inch to about 1 / 16 inch.

[0073] The bubbles in the nucleation chamber 60 are initially formed in a nucleation zone 65, which includes an initial mixture of gas and liquid streams, as previously discussed. As the bubble leaves this zone, it flows into a downstream growth region 74 and travels through a corresponding growth material 75. The material 75 is adapted and configured to provide a structured surface area on which individual bubble cells can attach to and combine with other bubble cells to divide into more bubble cells. The material 75 includes a number of structures that divide larger, more powerful cells into several smaller cells. In some embodiments, the material 75 is a mesh, preferably formed from a metal material. A plastic material can also be substituted if the organic material can withstand exposure to the liquid 22 used for cleaning. It is further contemplated by still other embodiments that the material 75 can be a material other than a mesh.

[0074] As the more divided foam cells exit growth region 74, they preferably enter a cellular structured region 78 that includes a material 79 within the interior foam passages of housing 61. Material 79 of cellular structured region 78 is adapted and configured to receive a first varying distribution of foam cell sizes from growth region 74 and provide a second smaller and narrower distribution of cell sizes to output 64. In some embodiments, structured material 79 includes a mesh formed from a metal, where the cell size of the mesh in region 78 is smaller than the mesh size of growth region 74.

[0075] After the fused (more abundant cells) and structured (improved uniformity) cells exit region 78, they enter a portion of a flow path that may be partially within housing 61 and partially outside housing 61, which flow path is adapted and configured to provide laminar flow of foam 28. Thus, the cross-sectional area of ​​laminar flow region 82 is preferably larger than the representative cross-sectional flow area of ​​nucleation region 65, growth region 74, or structured region 78. Flow region 82 encourages laminar flow and discourages turbulent flow that may otherwise reduce foam quantity or quality. Additionally, the output region of device 60 is generally smooth, along with the flow passageway extending to nozzle 30, with a sufficiently gradual turn radius to further encourage laminar flow and discourage turbulent flow.

[0076] 16 illustrates a nucleation chamber 260 according to one embodiment of the present invention. A housing 261 includes a gas inlet 262, a liquid inlet 263, and a foam outlet 264, with a foam formation passageway disposed between the inlets and outlets. Contained within the cylindrically shaped housing 261 is a generally cylindrically shaped gas tube 266 which receives gas under pressure from the inlet 262. Although the gas chamber 266 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into the liquid stream such that bubbles result.

[0077] Gas tube 266 is disposed generally coaxially within housing 261 (although coaxial orientation is not required) such that liquid from inlet 263 flows generally around the exterior surface of tube 266. Tube 266 preferably includes a plurality of spaced apart openings 270 adapted and configured to allow gas from within tube 266 to flow generally into a bubble-forming passage within housing 261. As shown in FIG. 16A, openings 270 are disposed generally along the length of tube 266, preferably circumferentially about the circumference of tube 266.

[0078] The nucleation, growth, and cell structuring zones (272, 274, and 278, respectively) are coaxially arranged. Nucleation zone 272 is formed between the outer circumference of tube or pipe 266. The wire mesh material 275 of growth region 274 wraps around the outer circumference of tube 266, which is best seen in FIG. 16F (where it is shown held in place by three electrical connection strips). Nucleation region 272 is formed between the outer circumference of pipe 266 and the innermost surface of growth material 275. When gas bubbles are emitted from openings 270 and pass through nucleation zone 272, bubbles are formed and bubble cells pass through one or more generally coaxial layers of mesh material 275. As the larger foam cells exit the material 275 of the growth region 274, the larger cells then proceed into an annularly arranged woven metal material 279 comprising a cell structured and homogenized region 278 (as best seen with reference to Figures 16C and 16F). With reference to Figure 16E, it can be seen that the material 279 of the homogenized region 278 in one embodiment tapers towards the centerline of the nucleation chamber 260. The foam cells are formed, increased in size, and homogenized by the mixing of liquid and gas in the manner previously discussed.

[0079] After the fused (grown) and structured (improved uniformity) cells exit region 278, they enter a portion of a flow path that may be partially within housing 261 and partially outside housing 261, which flow path is adapted and configured to promote laminar flow of foam 228 (best seen in Fig. 16E, Fig. 15A and Fig. 15B). It can be seen that the outer diameter of the flow path from outlet 264 to outlet 228-1 provided in cabinet 42 (best seen in Fig. 13B and Fig. 15A) is of approximately the same size as the outer diameter of nucleation chamber 260. However, the cross-section of nucleation chamber 260 (as can be visualized in Fig. 16A and Fig. 16F) has a smaller cross-sectional flow area than the cross-sectional flow area of ​​the piping downstream of outlet 264 (best seen in Fig. 15A), and the cross-sectional flow area of ​​the foam flow path within chamber 260 is partially blocked by materials 275 and 279. The flow area 282 (as best seen in Figures 15A and 15B) encourages laminar flow and discourages turbulent flow that may otherwise reduce the quantity or quality of the foam. Additionally, the output area of ​​the device 260 is generally smooth, along with the flow passageway extending to the nozzle 230, with a sufficiently gradual turn radius to further encourage laminar flow and discourage turbulent flow.

[0080] 18C illustrates a nucleation chamber 360 according to one embodiment of the present invention. A housing 361 includes a gas inlet 362, a liquid inlet 363, and a foam outlet 364, with a foam formation passageway disposed between the inlets and outlets. Contained within the housing 361 is a generally cylindrically shaped gas tube 366 which receives gas under pressure from the inlet 362. Although the gas chamber 366 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into the liquid stream such that bubbles result.

[0081] Gas tube 366 is disposed generally coaxially within housing 361 (although a coaxial arrangement is not required) such that liquid from inlet 363 flows generally around the exterior surface of tube 366. Tube 366 preferably includes a plurality of apertures 370 adapted and configured to allow gas from within tube 366 to flow generally into a bubble-forming passage within housing 361. As shown in FIG. 18C, apertures 370 are disposed generally along the length of tube 366, preferably circumferentially about the circumference of tube 366.

[0082] Nucleation zone 365 includes jets or perforations 370 arranged in a number of sub-zones, with the jets in such sub-zones 372 injecting gas into the flowing liquid at various angles of attack. A first nucleation zone 372a is disposed upstream of a second intermediate nucleation zone 372b, which is followed by a third nucleation zone 372c (each of which is disposed and spaced apart along the length of gas chamber 366). As shown in FIG. 18C, zone 372b overlaps both zones 372a and 372c, although other embodiments of the invention contemplate greater or lesser overlap, including no overlap.

[0083] The jets or perforations 370a in zone 372a are preferably adapted and configured to have an angle of attack generally opposite (or counter to) the main flow of liquid (flowing from left to right as viewed in FIG. 18C). By way of example, the centerline of these jets 370a is approximately 30-40 degrees from a line extending perpendicular to the centerline of the foam flow passage in chamber 360 (i.e., forms an angle of 60-50 degrees with the centerline). Thus, air exiting perforations 370a in zone 372a imparts energy to the surrounding liquid flow, which acts to decelerate the liquid (i.e., the velocity vector of the gas exiting nozzle 370a has an opposite component to the velocity vector of the liquid flowing from left to right in FIG. 18C of chamber 360).

[0084] Nucleation jets 370 in zone 372b are angled to impart a rotating vortex to the fluid in the foam flow path. In one embodiment, nucleation jets 370b are angled at about 30-40 degrees from perpendicular to the flow path centerline in a direction that imparts a tornado-like rotation in nucleation chamber 360.

[0085] The third nucleation zone 372c includes multiple jets 370c angled at approximately 30-40 degrees in a direction that pushes liquid axially in the general direction of flow within the bubble flow path (i.e., left to right, and generally opposite the angular orientation of jets 370a).

[0086] It is further understood that the perforations or nucleation jets 372 in zone 370 can have the attack angles described hereinabove, either entirely among all the jets or only partially among a portion of the jets. Other embodiments of the invention contemplate zones 372a, 372b, 372c in which only a portion of each of the jets 370a, 370b, or 370c are angled as described hereinabove, while the remainder of each of the jets 370a, 370b, or 370c are oriented differently. Furthermore, while what has been shown and described thus far is a first zone A having an attack angle opposite that of the fluid flow, followed by a second zone B having jets with an attack angle oriented to impart a vortex, followed by a third zone C having jets with an attack angle oriented to push bubbles toward an outlet, it is understood that various embodiments of the invention contemplate still other arrangements of the angled jets. As an example, still other embodiments contemplate a fluid vortex region located at the beginning or end of the nucleation zone. As a further example, yet another embodiment contemplates a counter-flow region (previously described as zone 372a) disposed toward the distal most end of the nucleation zone (i.e., oriented closer toward growth region 374). In yet another embodiment, there is a nucleation zone that comprises fewer zones than all three of zones A, B, and C, including those embodiments having holes disposed with only one of the characteristics of zones A, B, and C described thus far.

[0087] 18D illustrates a nucleation chamber 460 according to one embodiment of the present invention. A housing 461 includes a gas inlet 462, a liquid inlet 463, and a foam outlet 464, with a foam formation passageway disposed between the inlets and outlets. Contained within the housing 461 is a generally cylindrically shaped gas tube 466 which receives gas under pressure from the inlet 462. Although the gas chamber 466 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into the liquid stream such that bubbles result.

[0088] Gas tube 466 is generally coaxially disposed within housing 461 (although a coaxial arrangement is not required) such that liquid from inlet 463 flows generally around the exterior surface of tube 466. Tube 466 preferably includes a plurality of apertures 470 adapted and configured to flow gas from within tube 466 generally to a bubble-forming passageway within housing 461. As shown in FIG. 18D, apertures 470 are generally randomly disposed along the length of tube 466, preferably circumscribing the circumference of tube 466. However, still other embodiments of the present invention contemplate apertures 470 having locations limited to certain selected portions of tube 466, such as toward the inlet, toward the outlet, approximately in the center, or any combination thereof.

[0089] 18E illustrates a nucleation chamber 560 according to one embodiment of the present invention. A housing 561 includes a gas inlet 562, a liquid inlet 563, and a foam outlet 564, with a foam formation passageway disposed between the inlets and outlets. Contained within the housing 561 is a gas chamber or plenum 566 which receives gas under pressure from the inlet 562. Although the gas chamber 566 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into the liquid stream such that bubbles result.

[0090] Gas tube 566 is disposed generally coaxially within housing 561 (although a coaxial arrangement is not required) such that liquid from inlet 563 flows generally around the exterior surface of tube 566. Tube 566 preferably includes a plurality of apertures 570 adapted and configured to allow gas from within tube 566 to flow generally into a bubble-forming passage within housing 561. As shown in FIG. 18E, apertures 570 are disposed generally along the length of tube 566, preferably circumferentially about tube 566. However, still other embodiments of the present invention contemplate apertures 570 having locations limited to certain selected portions of tube 566, such as toward the inlet, toward the outlet, approximately in the center, or any combination thereof.

[0091] The openings in zones 572a, 572b, and 572c are generally positioned as previously described with respect to nucleation chamber 560. Figure 18E includes an inset showing a single nucleation jet 570a having an angle of attack 571a. The velocity vector of gas outlet jet 570a includes a velocity component that is opposite (i.e., upstream) to the general flow direction of the foam flow path from inlets 562 and 563 to outlet 564.

[0092] 18F illustrates a nucleation chamber 660 according to one embodiment of the present invention. A housing 661 includes a gas inlet 662, a liquid inlet 663, and a foam outlet 664, with a foam formation passageway disposed between the inlets and outlets. Contained within the housing 661 is a generally cylindrically shaped gas tube 666 which receives gas under pressure from the inlet 662. Although the gas chamber 666 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into the liquid stream such that bubbles result.

[0093] The gas tube 666 is disposed generally coaxially within the housing 661 (although a coaxial arrangement is not required) such that liquid from the inlet 663 flows generally around the exterior surface of the tube 666. The tube 666 preferably includes a plurality of apertures 670 adapted and configured to flow gas from within the tube 666 generally to a bubble-forming passageway within the housing 661. As shown in FIG. 18F, the apertures 670 are disposed generally along the length of the tube 666, preferably around the circumference of the tube 666. However, still other embodiments of the present invention contemplate the apertures 670 having locations limited to certain selected portions of the tube 666, such as toward the inlet, toward the outlet, approximately in the center, or any combination thereof.

[0094] The bubbles in the nucleation chamber 660 are first formed in a nucleation zone 665, which includes the initial mixing of the gas and liquid streams as discussed above. As the bubble leaves this zone, it flows downstream into a growth region 674 and travels over and around the ultrasonic transducer 675. In one embodiment, the transducer 675 is a rod (as shown), although it is understood that in yet other embodiments, the ultrasonic transducer may be of any shape adapted and configured to provide ultrasonic excitation to the bubbles exiting the nucleation zone 665. For example, yet other embodiments of the present invention contemplate a transducer having a generally cylindrical shape such that the bubbles flow through the inner diameter of the cylinder, and in some embodiments where the transducer is smaller than the inner diameter of the flow passage 661, the bubbles also travel across the outer diameter of the transducer. It is further understood that while one embodiment includes a transducer excited at ultrasonic frequencies, yet other embodiments contemplate a sensor that vibrates and imparts vibrations to the nucleated bubbles at any frequency, including audio and subsonic frequencies.

[0095] Referring to the small inset of FIG. 18F, the transducer 675 is preferably excited by an external electron source. In one example, the electron source provides an oscillating output voltage that excites a piezoelectric element in the transducer 675. The use of a vibrating type transducer has been found to be effective in converting a significant amount of the provided liquid into bubbles. Various embodiments of the present invention contemplate exciting vibrations in the transducer 675 with any type of vibration input, including one or more single frequencies, a frequency sweep over a range, or a random frequency input over a range of frequencies. In one test, a transducer provided by Sharpertek was excited at a frequency of over 25 kHz. Although a generally cylindrical transducer rod is shown, yet other embodiments contemplate any shape of vibration transducer, including side-mounted transducers, i.e., transducers that can be used in rectangular shaped chambers so that liquids and gases in the chamber flow close to the transducer to improve effectiveness. Additionally, while electronic excitation of the transducer 675 is contemplated in some embodiments, it is understood that in other embodiments the transducer 675 can be excited by other mechanical means, including by hydraulic or pneumatic input. Additionally, another embodiment contemplates the use of a vibration table within the cabinet 42 to physically shake the nucleation chamber. In such an embodiment, the inlet and outlet of the nucleation chamber are coupled to other piping within the cabinet by flexible fittings.

[0096] As the larger foam cells exit growth region 674, they enter a cell structured region 678 that preferably includes a material 679 within the interior foam passages of housing 661. The material 679 of cell structured region 678 is adapted and configured to receive a first larger distribution of foam cell sizes from region 674 and provide a second smaller, narrower distribution of cell sizes to output 664. In some embodiments, structured material 679 includes a mesh.

[0097] 18G illustrates a nucleation chamber 760 according to one embodiment of the invention. A housing 761 includes a gas inlet 762, a liquid inlet 763, and a foam outlet 764, with a foam formation passageway disposed between the inlets and outlets. Contained within the housing 761 is a generally cylindrically shaped gas tube 766 which receives gas under pressure from the inlet 762. Although the gas chamber 766 is illustrated as a cylindrically shaped tube, yet other embodiments of the invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into the liquid stream such that bubbles result.

[0098] The gas tube 766 is disposed generally coaxially within the housing 761 (although a coaxial arrangement is not required) such that liquid from the inlet 763 flows generally around the exterior surface of the tube 766. The tube 766 preferably includes a plurality of nucleation devices 770, each of which includes a plurality of small holes for the passage of air. As shown in the inset of FIG. 18G, in one embodiment, the device 770 is a porous metal filter muffler, such as those made by Alwitco of North Royalton, Ohio. These devices include a porous metal member attached to a threaded member. Air is provided from the threaded member to a porous material, which in one embodiment includes a variety of holes surrounding the periphery and ends of the porous member, the holes being anywhere from about 10 to 100 microns in diameter. Still other embodiments contemplate the use of a porous metal breather-vent-filter, such as those provided by Alwitco. Yet another embodiment contemplates device 770 including gas outlet passages similar to those of Alwitco's micro- and mini-muff mufflers.

[0099] More broadly, the device 770 includes an internal flow passage that receives gas under pressure from within the chamber 766. The end of the device 770 includes a number of holes (achieved, such as by using a porous metal, or by drilling, stamping, chemical etching, photoetching, electrochemical machining, etc.) in a pattern (random or ordered) such that gas from the internal passage of the device 770 flows around the mixture of liquids and forms bubbles. As best seen in FIG. 18G, in some implementations, the porous end of the device 770 is cylindrical in shape and extends into the liquid flow passage, while in yet other implementations, the porous end is generally flat, and in still other implementations, can be any shape. In some implementations, the device 770 has directionally oriented porosity such that the protruding end of the device is substantially non-porous on the upstream side and the downstream side of the device is porous. In such implementations, the bubbles form immediately behind the liquid as it travels over the protruding body of the device 770. As shown in FIG. 18G, in some embodiments, there are multiple devices 770 positioned along the length and around the circumference of (or otherwise extending from) the gas chamber 766.

[0100] Yet another embodiment contemplates the gas chamber 766 being fabricated from a porous metal, such as the porous metals discussed above. In such an embodiment, gas escapes from the chamber and enters the liquid flow path along the entire length of the porous structure. Additionally, some embodiments contemplate gas chambers constructed from materials that include a plurality of holes (formed by drilling, stamping, chemical etching, photoetching, electrical discharge machining, etc.).

[0101] 18H illustrates a nucleation chamber 860 according to one embodiment of the present invention. A housing 861 includes a gas inlet 862, a liquid inlet 863, and a foam outlet 864, with a foam formation passageway disposed between the inlets and outlets. Contained within the housing 861 is a generally cylindrically shaped gas tube 866 that receives gas under pressure from the inlet 862. Although the gas chamber 866 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into the liquid stream such that bubbles result.

[0102] Gas tube 866 is generally coaxially disposed within housing 861 (although coaxial orientation is not required) so that liquid from inlet 863 flows generally around the exterior surface of tube 866. Tube 866 preferably contains a plurality of devices 870 similar to nucleation jets 770 previously described.

[0103] The bubbles in the nucleation chamber 860 are initially formed in a nucleation zone 872 which includes an initial mixture of gas and liquid streams as previously discussed. As the bubble leaves this zone, it flows downstream into a growth region 874 and travels over a corresponding growth material 875. In some embodiments, the material 875 is a mesh, preferably formed from a metallic material. A plastic material can also be substituted if an organic material can withstand exposure to the liquid 822 used for cleaning. It is further contemplated by still other embodiments that the material 875 can be a material other than a mesh.

[0104] As the larger foam cells exit growth region 874, they preferably enter a cell structured region 878 that includes material 879 within the interior foam passages of housing 861. Material 879 of cell structured region 878 is adapted and configured to receive a first larger distribution of foam cell sizes from region 874 and provide a second smaller, narrower distribution of cell sizes to output 864. In some embodiments, structured material 879 includes a mesh formed from a metal, where the cell size of the mesh in region 878 is smaller than the mesh size of growth region 874. In one test, device 860 was successful in converting a large amount of liquid into foam.

[0105] 18I shows a nucleation chamber 960 according to one embodiment of the invention. A housing 961 includes a gas inlet 962, a liquid inlet 963, and a foam outlet 964, with a foam formation passageway disposed between the inlets and outlets. Contained within the housing 961 is a generally cylindrically shaped chamber 966 which receives gas under pressure from the inlet 962.

[0106] A gas chamber 966 is disposed generally within the foam flow path of the chamber 960 such that liquid from the inlet 963 flows generally around the exterior surface of the chamber 966. In one embodiment and as shown in the inset of FIG. 18I, the chamber 966 includes a number of radiator-like structures within the foam flow path. Each structure includes one or more main supply tubes 966.1 that provide gas from the inlet 962 to one or more cross tubes 966.2 that extend across the foam flow path. Each of these cross tubes 966.2 includes a number of nucleation jets 970 through which gas passes into the flowing fluid. In one embodiment, the cross tubes 966.2 are generally in intimate contact with a number of fin-like members 975 that extend generally across some or all of the cross tubes 966.2. Thus, the chamber 966 combines the nucleation zone 972 and each of the growth and / or homogenization regions 974 and 978 into a single device. As a result, liquid enters the upstream side of device 966 and bubbles exit the downstream side of device 966. In one embodiment, device 966 is similar to a computer chip cooling radiator and heat sink.

[0107] 18J shows a nucleation chamber 1060 according to one embodiment of the invention. A housing 1061 includes a gas inlet 1062, a liquid inlet 1063, and a foam outlet 1064, with a foam formation passageway disposed between the inlets and outlets. Contained within the housing 1061 is a gas chamber 1066 which receives gas under pressure from the inlet 1062.

[0108] In one embodiment, the chamber 1066 includes a supply plenum 1066.1 in fluid communication with a plurality of longitudinally extending tubes 1066.2. Preferably, each of the tubes 1066.1 and 1066.2 extend into the flow path of the nucleation chamber 1060 and further incorporate a plurality of nucleation jets 1070. As seen in FIG. 18J, in some embodiments, the tubes 1066.2 are arranged longitudinally such that liquid flows generally along the length of the tubes 106.2. However, in other embodiments, the tubes 1066.2 can also be arranged orthogonally in a manner similar to the tubes 966.2 described with respect to the nucleation chamber 960.

[0109] FIG. 18K shows a nucleation chamber 1160 according to one embodiment of the invention. A housing 1161 includes a gas inlet 1162, a liquid inlet 1163, and a foam outlet 1164, with a foam forming passageway disposed between the inlet and outlet. Contained within the housing 1161 is a nucleation zone 1172 including both a plenum 1166 for releasing gas into the foam flow path, and a motorized mixing device including an impeller 1186 driven by a motor 1184. In one embodiment, the impeller 1186 is coupled to a shaft and includes one or more curved stirring paddles similar to a paint stirring device. Gas from an outlet tube of the chamber 1166 is provided upstream of the stirring paddles. Foam formed in this manner has been found to be acceptable, although the foam cell size varies widely. Yet another embodiment includes a cell structured region 1178 (not shown) disposed downstream of the nucleation region 1172. Further examples of agitation members are shown in the inset of FIG. 18K, including devices 1186-1 and 1186-2. In one application, nucleation device 1186-1 resembles a coiled spring impeller, similar to those sold by McMaster Carr. In yet another embodiment, device 1186-2 is similar in structure to a hair dryer impeller. In some embodiments, the foam prepared in chamber 1160 is preferably created with liquid 1163 provided at a relatively low flow rate.

[0110] 18L, 18M, 18N, 18O, 18P, 18Q, and 18R show a nucleation chamber 1260 according to another embodiment of the present invention. These figures show various angular and other geometric relationships between various components of the nucleation device 1260. FIG. 18O shows that the first zone of nucleation 1272a can include a jet with a negative angle of attack, meaning that there can be a velocity component of the air exiting the gas plenum that is opposite to the general flow direction of the liquid flowing into the nucleation device. FIG. 18P and 18Q show that the downstream nucleation zones 1272b and 1272c can include an injection angle of the air that includes a velocity component in the same direction as the liquid flow (which has already passed through the first zone 1272a and is partially formed). FIG. 18R further shows the nucleation jet 1270 oriented to impart a vortex to the foamed mixture (i.e., rotation around the central axis of the nucleation device). It is further understood that various nucleation jets can have combinations of swirl angles as shown in FIG. 18R, with any of the alpha, beta, or rho angles as shown in FIG. 18O, FIG. 18P, or FIG. 18Q, respectively.

[0111] In some embodiments of the present invention, the total flow area of ​​all nucleation jets ranges from about 50 percent of the cross-sectional flow area N of the gas plenum to about three times the total cross-sectional flow area N of the glass plenum. To achieve this ratio of total nucleation jet area to total plenum cross-sectional area, the length NL can be adjusted accordingly. In yet other embodiments, the ratio of the cross-sectional area O of the inner diameter of the nucleation device to the area N of the gas plenum should be less than about 5.

[0112] FIG. 19 provides a pictorial illustration of aircraft engine cleaning according to various embodiments of the present invention. FIG. 19A shows a vehicle 21 parked between the wing and engine of a DC-9 series aircraft. FIGS. 19B and 19C show a vehicle 21 using a washing system 20 to clean the right engine of a DC-10 type aircraft. The vehicle 21 includes the washing system 20. A nozzle 30 is supported from an extendable boom 23 near the inlet 11 of the airframe-mounted engine 10. An effluent collector 32 is positioned near the exhaust 16 of the engine 10. The collector 32 in one embodiment includes a housing 33 coupled to a retaining member 34. The retaining member 34 in some embodiments is coupled to the vehicle 21 (or alternatively to the tarmac or other suitable restraint) to maintain the location of the collector 32 behind the engine 10 during the cleaning process. In some embodiments, the housing 33 is inflatable with air in a manner similar to a large outdoor playground equipment. In such an embodiment, the vehicle 21 further includes a blower for providing air under pressure to the housing 33 .

[0113] Foam from nozzle 20 supported by boom 23 is preferably provided into the inlet of engine 10 as engine 10 is rotated by its starter. Foam 28 is injected into inlet 11 as engine 10 is rotated on its starter. In some embodiments, normal operation of the starter results in a maximum engine free-running (i.e., non-operating) speed, which is typically less than engine idling (i.e., operating) speed. However, in some embodiments, a method utilizing system 20 preferably includes rotating the engine at a rotational speed less than the normal free-running speed. At such low speed operation, cooler zone components of engine 10 are less likely to reduce the quality or quantity of foam before it is provided to the engine hot zone. In one embodiment, a preferred rotational speed during cleaning is less than about 25 to about 75 percent of the free-running speed.

[0114] 2-1A and 2-1B depict various views of a washing or cleaning system 20 according to one embodiment of the present invention. Shown is a washing system 20 applied to cleaning a gas turbine engine, but it is understood that various embodiments of the present invention contemplate cleaning any object. The washing system 20 may be incorporated inside a vehicle 21. The vehicle 21 may also take the form of a trailer, compact car, or dolly that can move like the vehicle 21 to a desired location, with varying capacity.

[0115] FIG 2-1A pictorially depicts an aft-side view of an engine 10 being cleaned on the wing of an aircraft 90 in an airport. A vehicle 21 includes a washing system 20 for supplying a cleaning foam product to the engine 10 via a hose 33 lifted to the engine 10 by a support 34. It is also contemplated that the vehicle 21 may supply the support 34 or even a boom 23 (see FIG 2-2 below).

[0116] 2-1B pictorially depicts a front view of a cleaning system 20 used to clean a jet engine 10. The system 20 typically includes a gas supply 26 (not shown), a water supply 24, a cleaning chemical supply 22, and an electrical supply (not shown), all of which are provided to a foaming system 40. The foaming system 40 receives these input components and provides an output of foam 28 (not shown) to the inlet 11 of the engine 10 via a nozzle 30.

[0117] 2-2, 2-3 and 2-4 pictorially depict various embodiments of the positioning of the effluent collector 32 and vehicle 21. The effluent collector 32 is designed to collect foam and effluent for post-treatment, reuse (treatment unit 80, see below FIG. 2-7), or disposal.

[0118] FIG. 2-2 pictorially illustrates the effluent collector 32. The effluent collector 32 can be inflated similar to outdoor play equipment or similar to an aircraft emergency ramp or life raft. The effluent collector 32 in one embodiment provides structural support to contain foam, liquid, and solid particles in a manner that is safe and gentle for the aircraft. Additionally, the vehicle 21 can include a boom 23 that elevates the nozzle 30 (even larger on the nozzle 30 in FIG. 2-8). The boom 23 allows the nozzle 30 to be positioned for foam introduction to the engine 10. The boom 23 can have a combination or range of degrees of freedom in space in addition to, but not limited to, extension, rotation, and / or angle.

[0119] FIG. 2-3 pictorially depicts an effluent collector 32 (similar to FIG. 2-2) on a rather large jet engine 10. The vehicle 21 can be positioned in front of the engine 10, but is not limited to this one embodiment. For example, the jet engine 10 on the top rear of an aircraft 90 is high enough for the position of the vehicle 21 and boom 23 to reach the inlet (as in FIG. 8). In such a contemplated scenario, the effluent collector 32 can be elevated by another vehicle 21 with a boom 23 or by a support 34 (as in FIG. 2-1).

[0120] 2-4 pictorially depict one embodiment of the effluent collector 32. The collector 32 can be a floor mat with containment walls 37. In one example, the containment walls 37 are designed to be lifted by brackets or are designed to be inflatable. The effluent collector 32 can be of various sizes and dimensions to contain one or many engines 10 during the cleaning process.

[0121] FIG. 2-5 is a schematic and artist's photograph of an aircraft engine 10 being cleaned using a system according to one embodiment of the present invention. The engine 10 is mounted by aircraft 90 design, here the illustration shows a birotor helicopter (Bell) with the engine 10 mounted horizontally towards the rear, but another design has the engine 10 mounted on the side of the wing and pivots between vertical and horizontal (V22 Osprey). The vehicle 21 demonstrated in this photograph incorporates a trailer. The orientation of the engine 10 on the V22 aircraft is vertical, where a hose 33 directs the foam cleaning product to a nozzle 30 at the engine inlet 11. Cleaning or washing the engine 10 in this manner allows the engine regulations (more detailed in FIG. 2-10) to allow the core components of the engine 10 to alternate between rotating, stationary, or both, if possible. It is contemplated that the cleaning foam product can be channeled and dropped downwards without agitation / rotation. The effluent then exits the bottom of the engine 10 and is captured (similar to Figures 2-4) or directed to a sewer.

[0122] 2-7 are schematic diagrams of a cleaning process / method according to one embodiment of the present invention. As demonstrated in all previous figures, the apparatus and method of the present invention can enable versatility in the art. The schematic diagram shows a methodology of process steps for cleaning an engine 10. For illustrative purposes, the process begins in a vehicle 21 that includes a washing system 20. The washing system provides a foam cleaning product to clean the engine 10, where dirt, contaminants, liquids and foam, i.e., effluent, are discharged from the engine 10. Because site conditions and regulations vary (i.e., aircraft, private property, or military zones), the method and design of the present invention contemplates building modular flexibility into the vehicle 21. For example, the effluent has three method routes it can take, paths A, B, or C. In the first path A, the effluent can proceed directly to a sewer or to the ground. The effluent collector 32 system then allows the foam, liquid, and contaminated material to be recycled and / or treated by a treatment unit 80, shown by paths B or C. Vehicle 21 can house a processing unit 80 as shown in path B. Alternatively, in path C, processing unit 80 can be handled separately from vehicle 21. Processing unit 80 can be a pre-built module similar to those sold by AXEON Water Technologies.

[0123] 2-8A and 2-8B are similar schematic diagrams of an engine showing a foam injection system according to one embodiment of the present invention. The schematic diagram shows an enlarged front view of the engine 10 with the fan inlet 11 and compressor area. The two diagrams are shown to make this perspective easier to see, particularly the nozzle 30 associated with the engine 10. The nozzle 30 can be multiple nozzles and / or positional, angular and / or rotational articulating nozzles. For example, point A in both diagrams shows an articulating nozzle (i.e., a robot or monitor sold by Task Force Tips, a remote controlled monitor Y2-E11A) with a vertical tube (not limited in size) where the cleaning foam product can reach and be targeted to the compressor inlet 11 of the engine 10. Similarly, point B in both diagrams shows an articulating nozzle with a "Y" shaped nozzle outlet (although not limited in design) and positioned along the axis of rotation of the core of the engine 10, where the nozzle 30 can rotate axially along the compressor inlet 11 zone.

[0124] FIG. 2-9A is a schematic diagram of an engine cutaway interior showing a foam connection system 41 according to one embodiment of the present invention. The engine 10 typically includes a cold area including an inlet 11, a fan 12 (not shown), and one or more compressors 13. Compressed air is provided to the hot areas of the engine 10 including a combustor 14, one or more turbines 15, and an exhaust system 16. Because different engines have variations in wear and tear due to contaminating engines 10, manufacturers have dedicated tubes 42, connections, or passages designed for water washing procedures. The present invention shows that the foam cleaning system has an improvement with reference to FIG. 2-5, so that nozzles 30 or hoses 33 can again be directly connected to one or many of the foam connection points 41 (dashed lines) to target specific, some, or all engine areas.

[0125] As an example, some compressor regions are known to include one or more manifolds or tubes that carry compressed air, such as to provide bleed air to the aircraft or to provide relatively cool compressed air for cooling hot regions of the engine. In some embodiments, cleaning foam is provided to the engine through these manifolds or tubes. The foam can be provided while the engine is rotating or when the engine is stationary. Additionally, engine hot regions are known to include tubes or manifolds that receive cooler compressed air for the purpose of cooling the hot regions, and blanked off ports that are used for boroscope inspection or other purposes. Still other embodiments of the present invention contemplate introducing foam into such tubes and ports in stationary or rotating engines.

[0126] 2-9B are schematic cutaway views of an engine with internal and external components showing a foam connection system according to one embodiment of the present invention. In a similar manner to FIGS. 2-9A, the cutaway view of engine 10 includes inlet 11, fan 12, compressor 13 area, combustor 14 area, turbine 15 area, and exhaust 16 area. Regardless of existing or future engine manufacturing engineering modifications, tubes 43, passages, and connections can be used to deliver foam for cleaning engine 10 areas. Referring to FIG. 2-1B, hose 33 is shown adapted to connect to nozzle 30, however, alternatively, hose 33 can be directly connected to engine 10 at one or more points of connection 41.

[0127] 2-10 are graphs of engine cleaning spin cycle prescriptions according to one embodiment / method of the present invention. As demonstrated in the immediate figures, the engine 10 can be mounted in numerous ways (i.e., horizontal, vertical) and the engine can come in numerous shapes and sizes. With this in mind, the foam cleaning procedure can work more effectively at a prescribed engine 10 core speed (compressor 13 area and turbine 15 area). By way of example, the graph has three types of core speeds (from compressor 13 to turbine 15 linked by three individual-shafts) shown as N1, N2, and N3. The Y-axis is the maximum allowable rotational speed (actual values ​​not shown, scale is for illustration only). The X-axis is time (not to scale, for example only). The purpose of the engine cleaning prescription is to spin and agitate the foam that has overflowed into the gas path inside the engine 10. The foam comes into contact with, scrapes off, and removes contaminants. The foam has different fluid dynamic properties at different rotational (agitation) speeds. Thus, by cycling the engine 10 at various speed ranges, the cleaning effect can be achieved. The figure shows that the engine 10 is cranked three times (3 cycles), but is not limited to this frequency. By evaluating the first cycle, it is clear that N1, N2, and N3 behave according to inertial quantities. At zero, where N1, N2, and N3 are zero, when the engine is cranked one unit, N1, N2, and N3 reach ceilings of about 10.5%, 8.5%, and 5.8%, respectively. The spilled foam product inside the engine 10 causes N3 to stop more quickly due to hydrodynamic friction, while in comparison, N1 can maintain rotation for longer. Although it is preferable to cycle once or many times in the regulation, the engine 10 can also be cleaned without rotation by injecting and spilling into the gas path as discussed in Figures 2-5. The foam temperature is useful for the frequency and amplitude of the cycling regulation. The vehicle 21 can accommodate a heater 38 to regulate and positively affect the cleaning regimen.

[0128] FIG. 2-11 is a graphical representation of one method of the present invention for engine monitoring and benefit quantification. The positive impacts and benefits of properly cleaning the engine 10 can be further quantified in the present invention. Diagnostic or telemetry tools are used to obtain financial, operational, maintenance, and environmental (i.e., carbon credits, on-wing time, fuel savings, etc.). Data analysis tools are a scientific method to enhance the life and safety of the engine 10. As shown in FIG. 2-11, one embodiment of the present invention includes a method. For example, the engine 10 in an aircraft or boat transmits information to a data center. The engine operator or manufacturer then requests the foam engine cleaning method via computer automation, either separately or with a trained professional. When the foam cleaning method is performed in conjunction with this monitoring method, performance recovery metrics can log improvements. These quantified improvements can be collected in terms of financial goals, carbon credits, engine life extension, and / or safety.

[0129] Figures 2-12 show various embodiments of a portable effluent collector according to one embodiment of the present invention. The effluent collector includes a trailer 232.1 having a number of wheels supporting it from the ground, and preferably also including a trailer hitch for towing by another vehicle. The trailer includes a cargo compartment that can be adapted and configured to support and contain the foam effluent during the engine cleaning process. As shown in these figures, the cargo compartment is lined with a plastic, waterproof and watertight flexible sheet, thereby forming a collection pool 232.2 that is generally supported by the wheels.

[0130] The trailer preferably includes a plurality of collection devices that can be conveniently folded into a compact configuration for transport and that can also be extended and supported in an upright position for collection of foam during the cleaning process.

[0131] FIG. 2-12 shows the trailer and collection device in an extended state suitable for collecting foam during the cleaning process. The exhaust collector 232.3 is formed by a flexible sheet that is waterproof and watertight and is separated by a pair of spaced ribs 232.34. Each of the support ribs is located on either side of the trailer, each of which is pivotally connected to the forward end of the trailer 232.1. Preferably, the sheet is of sufficient size to be loosely draped over the ribs so that, in a vertically supported state, the sheet forms an enclosure 32.31 having an inlet 232.34 for the collection of foam exiting the engine exhaust. The enclosure 232.31 forms a gravity-assisted flow path from the inlet to a drain located proximal to the pool 232.2. Any foam received at the inlet flows downwards within the enclosure and enters the pool via the drain. A pair of vertical supports 232.33 are provided on either side of the enclosure. Each of the vertical supports connects at one end to a side of the trailer and at another end to a corresponding rib. The ribs and corresponding vertical supports lock together in the extended position (as shown in Figures 2-12) to maintain the enclosure in an upright position. When the ribs and vertical supports disengage, the ribs can be folded toward the rear of the trailer and the vertical supports can be folded toward the front of the trailer or removed for transport purposes.

[0132] The aft end of the trailer 232.1 includes a collector 232.4 adapted and configured to capture runoff from the inlet of the engine being washed, and also from underneath the engine if the nacelle door is open. The collector 232.4 extends from the forward end of the trailer 232.2 and, when supported by the vertical supports 232.43, is angled upwards towards the inlet of the engine being washed. Any foam exiting the engine inlet or exiting the engine nacelle falls onto the drainage path formed by the support of the sheet 232.41 between pairs of spaced, substantially parallel support ribs 232.42. Each of these ribs is pivotally connected to the forward end of the trailer. Each of the vertical supports 232.43 is attached to a rib and contacts the ground. Any foam falling onto the drainage path of the concave sheet 232.41 moves by gravity towards the pool 232.2.

[0133] Various aspects of different embodiments of the present invention are presented in paragraphs X1, X2, X3, X4, X5, X6 and X7 as follows.

[0134] X1. One aspect of the invention relates to an apparatus for foaming a water-soluble liquid cleaning agent, the apparatus comprising a housing having a plurality of sequentially arranged foam manipulation sections or regions, the housing having a gas inlet, a water-soluble cleaning agent liquid inlet, and a foam outlet, one region or region including a pressurized gas injection device having a plurality of openings, the interior of the housing forming a mixing region receiving liquid from the liquid inlet and gas released from the openings to form foam having a first average cell size and a first range of cell sizes, another foam manipulation section receiving cells having a first distribution range and a first average size and flowing these over a cell attachment and growth member providing a surface area for cell attachment and fusion to form foam having a second, larger average cell size, and yet another foam manipulation section or region adapted to receive foam having a first range of cell sizes and flow the foam through a foam structuring member configured to reduce the range of foam sizes and provide a more uniform foam output.

[0135] X2. Another aspect of the invention relates to a method of foaming a liquid, comprising mixing a liquid and a pressurized gas to form a foam, flowing the foam through a member to increase the size of the cells, and then flowing the foam through a plurality of openings or a grid to reduce the size of the cells.

[0136] X3. Yet another aspect of the invention relates to a system for providing an air-foamed water-soluble liquid cleaning agent, the system comprising: an air pump providing air at a pressure greater than ambient pressure; a liquid pump providing water-soluble liquid under pressure; an air inlet receiving air from the air pump; a liquid inlet receiving liquid from the liquid pump; and a foam outlet, a nucleation device that turbulently mixes the pressurized air and liquid to form a foam; and a nozzle receiving the foam through a foam conduit, the internal passages of the nozzle and conduit being adapted and configured to reduce turbulence of the foam, and the nozzle being adapted and configured to deliver a low velocity stream of foam.

[0137] X4. Yet another aspect of the invention relates to a method of supplying an air-foamed water-soluble liquid cleaning agent to an inlet of a jet engine installed in an aircraft, the method including the steps of providing a source of water-soluble liquid cleaning agent, a liquid pump, an air pump, a turbulent mixing chamber, and a non-atomizing nozzle; mixing pressurized air and pressurized liquid in the mixing chamber to form a supply of foam; positioning the nozzle in front of the installed inlet; and flowing the supply of foam from the nozzle into the installed inlet.

[0138] X5. Another aspect of the present invention relates to an apparatus for foaming an aqueous liquid cleaning agent, comprising: means for mixing pressurized gas with a flowing aqueous liquid to form foam; means for growing the size of the foam cells; and means for reducing the size of the grown cells.

[0139] X6. Yet another aspect of the present invention relates to a method for planning foam cleaning of a jet engine, the method including the steps of quantifying a range of improvements to operating parameters of a group of jet engines achievable by foam cleaning of a group of components of the jet engine, operating the group of engines installed on an aircraft for a period of time, measuring performance of the engines during operation, determining that the engine should be foam cleaned, and scheduling foam cleaning of the engine.

[0140] X7. Yet another aspect of the invention relates to an apparatus for foam cleaning of a gas turbine engine comprising: a multi-wheel trailer having a cargo compartment with a waterproof liner; an exhaust outflow foam collector having a first sheet supported by a first pair of spaced apart ribs, the first ribs pivotally coupled to one end of the trailer, the ribs and the sheet cooperating to form an enclosed flow passage, one end of the flow passage having an inlet for receiving foam and the other end of the flow passage having a drain adapted and configured to provide foam outflow to the liner; and an inlet foam collector having a second sheet supported by a second pair of spaced apart ribs, the second ribs pivotally coupled to the other end of the trailer, the ribs and the sheet cooperating to provide a drain path to the liner.

[0141] Further embodiments relate to any of statements X1, X2, X3, X4, X5, X6, or X7 above in combination with one or more of the following other aspects: It is also understood that any of the preceding X clauses includes a listing of individual features that can be combined with individual features of other X clauses.

[0142] Here, the first flow portion, the second flow portion, and the third flow portion have approximately the same flow area.

[0143] Here, the housing has an inner wall and an internal axis, and the direction of the internal flow passage is from the axis to the inner wall.

[0144] wherein at least two of the first, second, and third flow portions are coaxial, or the third flow portion is outermost from the first or second portions, or the first flow portion is innermost from the second or third portions.

[0145] The first, second and third flow portions are coaxial, and the second flow portion is between the first and second portions.

[0146] The direction of the internal flow path is from the liquid inlet to the foam outlet.

[0147] The growth member includes a wire mesh.

[0148] The wire mesh has a first mesh size and the structuring member includes a wire mesh having a second mesh size smaller than the first mesh size.

[0149] The mesh comprises a plastic material or a metal material.

[0150] The structuring member may include an apertured plate, a lattice, or a fibrous matrix.

[0151] Forcing the first bubble onto the member increases the turbulence of the first bubble.

[0152] The method further includes flowing the third foam into a chamber having an inlet and an outlet, the chamber adapted and configured to reduce turbulence of the third foam.

[0153] The chamber is adapted and configured to provide a more laminated flow of the third foam between the inlet and the outlet.

[0154] The mixing involves flowing the liquid in a first direction and injecting a gas in a second direction having a velocity component at least partially opposite to the first direction.

[0155] Flowing the second foam with a velocity further includes flowing a third foam over the object at about the same velocity to clean the object.

[0156] The nozzle is adapted and configured to provide a stream of foam into a bleed duct of a jet engine.

[0157] The nozzle is adapted and configured to provide a stream of foam to a manifold of tubes attached to a jet engine.

[0158] The stream has a substantially constant diameter.

[0159] The nozzle has a first flow area and the conduit has a second flow area, the first flow area being approximately the same as the second flow area.

[0160] The foam outlet has a first flow area and the conduit has a second flow area, the first flow area being approximately the same as the second flow area.

[0161] The nozzle is one or more nozzles having a total flow area and the foam outlet has an exit area, the exit area being approximately the same as the total flow area.

[0162] The nucleation device includes an air-pressurized plenum having a plurality of air flow openings and disposed within a chamber to which a flow of liquid is provided, the openings releasing air into the flowing liquid to form bubbles.

[0163] The air received by the nucleation device has a pressure greater than about 10 psig and less than about 120 psig, and the liquid received by the nucleation device has a pressure greater than about 10 psig and less than about 120 psig.

[0164] The incoming feed is at a velocity greater than about 3 feet per second and less than about 15 feet per second.

[0165] The flowing feed is a uniform stream of approximately constant diameter.

[0166] The provision includes a cell growth chamber downstream of the mixing chamber and further includes growing the size of the foam cells after mixing and before pouring.

[0167] The provision includes a turbulence reduction chamber downstream of the mixing chamber and further includes reducing turbulence of the mixed foam after mixing and prior to pouring.

[0168] The mounted engine is approximately vertical in orientation and the pour is into the mounted inlet without engine rotation.

[0169] The growing means includes a growing mesh and the reducing means includes a reducing mesh, the mesh size of the reducing mesh being smaller than the mesh size of the growing mesh.

[0170] The growing means is adapted and configured to provide a surface for attachment and fusion of the foam cells from the mixing means.

[0171] The growing means includes a plurality of first passages, and the reducing means is adapted and configured to reduce the size of at least some of the grown cells by passing the grown cells through a plurality of second passages that are smaller than the first passages.

[0172] The mixing means is to inject gas into the flowing liquid from within the tube.

[0173] The mixing means is by providing pressurized gas into the liquid flowing through a porous metal filter.

[0174] The mixing means includes a motorized rotating impeller.

[0175] The mixing means imparts vortices to the flowing liquid by injecting gas.

[0176] The growing means is a vibrating rod or an ultrasonic transducer.

[0177] Further, it is up to the engine owner to determine, including providing the engine owner with, the measured performance of their particular engine.

[0178] The operating parameter is the activation time.

[0179] The operating parameter is the fuel consumption rate of the engine.

[0180] The operating parameters are the carbon or nitrogen oxides emitted by the engine.

[0181] The measuring occurs during commercial passenger aircraft operation.

[0182] Further included is a vertical support attached at one end to the trailer and at the other end to one of the first ribs, the vertical support maintaining the enclosed flow path upright to facilitate gravity induced drainage from the inlet to the drain.

[0183] Further included is a vertical support attached at one end to the trailer and at the other end to one of the second ribs, the vertical support maintaining the drainage path at an upward angle to facilitate gravity induced flow toward the liner.

[0184] While the invention has been illustrated and described in detail in the drawings and foregoing description, it is to be considered as illustrative and not restrictive in construction, it being understood that only specific embodiments have been shown and described, and that all changes and modifications which come within the scope of the invention are desired to be protected.

Claims

1. 1. A method for cleaning a gas turbine engine on an aircraft, the method comprising: providing pressurized gas, water and cleaning chemicals to a foaming system to generate foam; injecting the foam into one of an inlet or a compressor of the gas turbine engine; scrubbing contaminants from a combustor of the gas turbine engine with the injected foam; exhausting the foam and the contaminants through an exhaust nozzle; collecting the expelled foam and contaminants in an effluent collector; A method comprising:

2. The method of claim 1 , further comprising the step of flowing the collected foam and contaminants to a treatment unit.

3. The method of claim 1 further comprising the step of recycling the collected foam and contaminants to an inlet of the foaming system.

4. The method of claim 1 , further comprising operating the gas turbine engine, and wherein the injecting occurs during the operation.

5. The method of claim 1 , wherein the effluent collector extends beneath the gas turbine engine.

6. The method of claim 1 , wherein the effluent collector has a drain configured to drain the collected foam and contaminants.

7. The method of claim 1 , wherein the effluent collector is supported by a vehicle.

8. The method of claim 1 , wherein the effluent collector has an expandable wall.

9. The method of claim 1 , wherein the effluent collector extends from below an inlet of the gas turbine engine to below an exhaust nozzle of the gas turbine engine.

10. The method of claim 1, wherein the effluent collector is positioned in the tarmac beneath the gas turbine engine.

11. The method of claim 1, wherein the foam is supplied by a non-atomizing nozzle.

12. The method described in claim 1, wherein the gas turbine engine is a multi-shaft gas turbine engine and includes a compressor, and the foam is first caused to flow into the compressor.

13. The method described in claim 1, wherein the gas turbine engine is a multi-shaft gas turbine engine and includes a compressor, and the foam is caused to flow into the compressor.

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