Online Lotus Thrust Adjustment System

Abstract

An online Lotus thrust adjustment system is disclosed. The online Lotus thrust adjustment system includes at least one axial thrust balance flow net (16) between a compressor (12) and an expander (11) of a gas turbine. The axial thrust balance flow net (16) supplies high-pressure gas from the compressor (12) to an axial thrust balance piston cavity, and an open-loop flow regulator (17) is arranged along the axial thrust balance flow net (16).

Description

Technical Field

[0001] The present disclosure relates to a system for balancing the loads on the thrust bearings of a gas turbine engine rotor. Embodiments disclosed herein specifically relate to adjusting the thrust of the rotor in real time using a manually operated control valve from outside the engine package.

Background Art

[0002] The rotating components of a turbine unit always generate an axial thrust under the action of the pressure difference between the intake and exhaust ports.

[0003] For example, in an "oil & gas" application, the axial thrust applied to the bearings of a gas turbine can typically be in the range of 10,000 N to 100,000 N.

[0004] Providing a thrust bearing that can withstand such high axial thrust is very difficult and expensive.

[0005] To solve this problem, high-pressure gas from the compressor is used and supplied into the piston cavity to balance at least part of the axial thrust.

[0006] Processes have been developed to test balance systems and associated control units during manufacturing to ensure that complex algorithms are properly calibrated. However, similar processes or systems are not available for complex algorithms that are recalibrated in the field when the engine undergoes changes from its original operating profile and configuration, such as those caused by deterioration, wear, or replacement of parts. Typically, this also occurs during initial installation or in the case of changes in operating configuration (e.g., water injection). Each of these factors directly affects the engine components, which in turn affect the load on the lotus thrust bearings, and correspondingly, the amount of pressure required in the balance piston cavity to offset such loads. Currently, this airflow regulation is managed by online fixed orifices mounted on properly designed machines. Whenever recalibration is required, the fixed orifices are replaced by physically disassembling the line, causing machine downtime.

[0007] Therefore, it is highly desirable to develop a system in which the axial thrust balance control unit is calibrated while the engine is operating in the field. Furthermore, it is desirable that this calibration process be performed during normal engine operation without requiring a shutdown.

[0008] Most importantly, to enhance the overall reliability of the system, it is desirable that such a lotus thrust adjustment system be operated via an open-loop control system. [Overview of the project]

[0009] In one embodiment, the subject matter disclosed herein relates to an online lot thrust adjustment system comprising at least one axial thrust balance flow net positioned between the compressor and expander of a gas turbine, wherein the axial thrust balance flow net supplies high-pressure gas from the compressor to the expander to balance the axial thrust at least partially, and an open-loop flow regulator positioned along the axial thrust balance flow net adjusts the size of the passage through the axial thrust balance flow net.

[0010] In another embodiment, the subject disclosed herein relates to an online lotus thrust adjustment system, wherein a manual valve is positioned along an axial thrust balance flow net, the manual valve comprises a stem and a wheel, the wheel and a portion of the stem are positioned outside the gas turbine enclosure, and the wheel is detachably coupled to the stem. In particular, according to this embodiment of the subject disclosed herein, at least a portion of the axial thrust balance flow net is composed of a flexible hose.

[0011] In another embodiment, an online lotus thrust adjustment system is disclosed herein, wherein an open-loop flow regulator is positioned along an axial thrust balance flow net, and the lotus thrust adjustment system comprises instrumentation for reading thrust balance pressure, safety instrumentation, and a graphic control panel page for identifying balance pressure, valve position, and equivalent reference orifice size.

[0012] The lotus thrust adjustment system described herein is intended to replace conventional lotus thrust adjustment systems with a new circuit based on the use of manual valves instead of the orifices currently used, thereby regulating the correct flow rate and pressure of a balanced line. The weight and dimensions of the components of the lotus thrust adjustment system described herein are such that the operator can assemble the equipment on-site without lifting it. [Brief explanation of the drawing]

[0013] Many of the disclosed embodiments of the present invention and their associated advantages will be better understood by referring to the following embodiments for carrying out the invention, and a more complete understanding will be easily obtained, as they will be better understood when considered in relation to the accompanying drawings. [Figure 1] Figure 1 shows a schematic diagram of a first gas turbine including the online lotus thrust adjustment system according to this disclosure. [Figure 2] Figure 2 shows a schematic diagram of a second gas turbine including the online lotus thrust adjustment system according to this disclosure. [Modes for carrying out the invention]

[0014] Next, one embodiment of the present disclosure will be described in detail, an example of which is shown in the drawings. Such examples are not limiting to the present disclosure and are provided for illustrative purposes only. It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the scope or spirit of the present disclosure. Throughout this specification, any reference to “one embodiment,” “one embodiment,” or “several embodiments” means that a particular feature, structure, or characteristic described in relation to one embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrase “in one embodiment,” “in one embodiment,” or “several embodiments” in various places throughout this specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any preferred manner in one or more embodiments.

[0015] When presenting elements of various embodiments, the articles "a," "an," "the," and "said" are intended to indicate that there is one or more of those elements. The terms "comprising," "including," and "having" are intended to be non-exclusive, meaning that additional elements other than those listed may exist.

[0016] Referring here to the drawings, Figure 1 shows a schematic diagram of an exemplary gas turbine. The gas turbine engine consists of an expander 11 and a compressor 12, the expander 11 being mechanically connected to the compressor 12 by a shaft 20. The expander 11 is further connected to the compressor 12 via a line 14, which supplies gas from the compressor 12 to the expander 11. A combustor 13 is located along the line 14 and is configured to ignite the gas received from the compressor 12, thereby increasing its volume. The combustion gas is then supplied to the expander 11, where the potential energy of the combustion gas is converted into kinetic energy. The gas turbine is housed in an enclosure 15 to isolate it from the outside. In particular, cooling air is supplied to the chamber between the gas turbine and the enclosure 15 to control the temperature of the gas turbine and keep the temperature of the enclosure 15 within a safe level.

[0017] Figure 1 also shows a lotus thrust adjustment system according to an embodiment of the present disclosure. In particular, the lotus thrust adjustment system is located between the compressor 12 and the expander 11 and includes an axial thrust balance flow net 16 that connects the compressor's secondary flow system to the turbine's secondary flow system. A portion of the high-pressure gas from the compressor 12 is taken out of the compressor 12 and supplied to the turbine 11, in particular to the axial thrust balance piston cavity, and the pressure of the gas is used to counteract lotus thrust.

[0018] A flow regulator 17 positioned along the axial thrust balance flow net 16 is also shown. In particular, the flow regulator 17 is an open-loop flow regulator 17 and consists of a manual valve 17 with a stem 18 and a wheel 19, the wheel 19 and a portion 18' of the stem 18 located outside the gas turbine enclosure 15. Manual operation by the handwheel 19 does not preclude the possibility of electric operation.

[0019] At least a portion of the axial thrust balance flow net 16 is composed of flexible hoses to absorb the thermal expansion and vibration of the engine, prevent mechanical stress from being transmitted to the enclosure 15, support the manual valve 17, and prevent static and dynamic stress from being transmitted to the flange on the machine. The valve needs to have a wheel 19 located outside the enclosure 15 for manual operation from the outside. However, the valve body, as well as all the piping of the axial thrust balance flow net 16, remains inside the enclosure, considering the high temperatures and noise generated during gas turbine operation. Flexible metal hoses can be conveniently used, and solutions are employed that minimize their diameter to avoid obstruction and thus have internal liners to enable operation at high-speed flows. The materials and hose structure are designed to suit any specific gas turbine operating pressure and temperature.

[0020] The valve wheel 19 is removable and located outside the enclosure wall to avoid overheating, which could be harmful to the operator.

[0021] In some embodiments, globe valves are used because they are among the most reliable valves in terms of position retention and restorative force against failure.

[0022] The operating position of valve 17, which must mimic the function of an orifice in conventional technology, is guaranteed by using calculations and diagrams that correlate the valve opening degree with different orifice sizes.

[0023] Referring next to Figure 2, the online lotus thrust adjustment system according to this disclosure can also be applied to a turbine engine. The same reference numerals represent the same or corresponding parts, elements, or components already shown in Figure 1 and described above, and are not described again here. The output turbine 21 is additionally shown downstream of the compressor 12 and the expander 11 (sometimes called the “high-pressure turbine” or “high-pressure expander”), and provides kinetic energy to the load 22.

[0024] While aspects of the present invention have been described in relation to various specific embodiments, it will be apparent to those skilled in the art that many modifications, changes, and omissions are possible without departing from the spirit and scope of the claims. In addition, unless otherwise specified herein, the order or arrangement of any process or method step may be changed or rearranged according to alternative embodiments.

Claims

1. An online lot thrust adjustment system for balancing the load on the lot thrust of a gas turbine in operation in response to deviations from the design operating profile and configuration of the gas turbine, wherein the gas turbine comprises an expander (11) located downstream of a compressor (12), a combustor (13) configured to receive gas from the compressor (12) via a line (14), achieve gas combustion, and supply the combustion gas to the expander (11), the gas turbine (10) is housed in an enclosure (15), the lot thrust adjustment system comprises an axial thrust balance flow net (16) between the compressor (12) and the expander (11) to supply high-pressure gas from the compressor (12) to an axial thrust balance piston cavity, and the lot thrust adjustment system comprises an open-loop flow regulator (17) located along the axial thrust balance flow net (16), The open-loop flow regulator (17) is a manual valve (17) comprising a stem (18) and a wheel (19), wherein the wheel (19) and a portion (18') of the stem (18) are located outside the gas turbine enclosure (15). The wheel (19) is detachably coupled to the stem (18) and is used to manually operate the manual valve (17) from outside the gas turbine enclosure (15). An online lotus thrust adjustment system characterized by the following features.

2. The online lotus thrust adjustment system according to claim 1, wherein at least a portion of the axial thrust balance flow net (16) is made of a flexible hose.

3. The online lotus thrust adjustment system according to claim 1, wherein the open-loop flow regulator (17) is a globe valve.

4. The online lotus thrust adjustment system according to claim 1, wherein the open-loop flow regulator (17) is adjusted by a table that replicates the equivalent reference orifice size.

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