47 results about "Streaming instability" patented technology

A fluidic oscillator suitable for use at colder temperatures for generating an exhaust flow in the form of an oscillating spray of fluid droplets has an inlet for pressurized fluid, a pair of power nozzles configured to accelerate the movement of the pressurized fluid, a fluid pathway that connects and allows for the flow of pressurized fluid between its inlet and the power nozzles, an interaction chamber which is attached to the nozzles and receives the flow from the nozzles, a fluid outlet from which the spray exhausts from the interaction chamber, and a means for increasing the instability of the flow from the power nozzles, with this means being situated in a location chosen from the group consisting of a location within the fluid pathway or proximate the power nozzles. In a first preferred embodiment, the flow instability generating means comprises a protrusion that extends inward from each side of the fluid pathway so as to cause a flow separation region downstream of the protrusions. In a second preferred embodiment, the flow instability generating means comprises a step in the height elevation of the floor of the power nozzles with respect to that of the interaction chamber.

A solar thermal power generator includes an inclined elongated boiler tube positioned in the focus of a solar concentrator for generating steam from water. The boiler tube is connected at one end to receive water from a pressure vessel as well as connected at an opposite end to return steam back to the vessel in a fluidic circuit arrangement that stores energy in the form of heated water in the pressure vessel. An expander, condenser, and reservoir are also connected in series to respectively produce work using the steam passed either directly (above a water line in the vessel) or indirectly (below a water line in the vessel) through the pressure vessel, condense the expanded steam, and collect the condensed water. The reservoir also supplies the collected water back to the pressure vessel at the end of a diurnal cycle when the vessel is sufficiently depressurized, so that the system is reset to repeat the cycle the following day. The circuital arrangement of the boiler tube and the pressure vessel operates to dampen flow instabilities in the boiler tube, damp out the effects of solar transients, and provide thermal energy storage which enables time shifting of power generation to better align with the higher demand for energy during peak energy usage periods.

A device for controlling fluid flow. The device includes an arc generator coupled to electrodes. The electrodes are placed adjacent a fluid flowpath such that upon being energized by the arc generator, an arc filament plasma adjacent the electrodes is formed. In turn, this plasma forms a localized high temperature, high pressure perturbation in the adjacent fluid flowpath. The perturbations can be arranged to produce vortices, such as streamwise vortices, in the flowing fluid to control mixing and noise in such flows. The electrodes can further be arranged within a conduit configured to contain the flowing fluid such that when energized in a particular frequency and sequence, can excite flow instabilities in the flowing fluid. The placement of the electrodes is such that they are unobtrusive relative to the fluid flowpath being controlled.

A capillary electrophoresis device and separation protocol uses a hydraulic resistance-providing structure (HRPS) in the main separation channel to separate the divide the main separate channel into an upstream portion and a downstream portion. The HRPS may take the form of a porous plug, or a solid plug provided with at least one shallow channel. A sample separates and migrates through the porous structure or the shallow channel, upon application of a voltage difference between the upstream and downstream sides. Among other things, the HRPS helps reduce electrokinetic flow in the presence of conductivity gradients and facilitates robust, high-gradient on-chip field amplified sample stacking. The HRPS also enables the use of a pressure-injection scheme for the introduction of a high conductivity gradient in a separation channel and thereby avoids flow instabilities associated with high conductivity gradient electrokinetics. The approach also allows for the suppression of electroosmotic flow (EOF) and benefits from the associated minimization of sample dispersion caused by non-uniform EOF mobilities. An injection procedure employing a single pressure-flow high-conductivity buffer injection step followed by standard high voltage control of electrophoretic fluxes of sample, may be employed.

A valve arrangement (10) for reducing the instability of fluid flow in a compressible flow governor valve includes a cutoff plug (12) with a lateral concave surface (14) and an end portion (16) having a substantially circular cross section, and a seat (30) with a convex surface (32). The lateral concave surface (14) and the end portion (16) of the cutoff plug (12) define an abrupt cutoff corner (18). The radius (re) of the end portion (16) of the cutoff plug (12) is less than the radius (Rs) of the seat (30). The radius of curvature (R) of the seat (30) is less than the radius of curvature (rq) of the lateral concave surface (14) of the cutoff plug (12). The configuration of the cutoff plug (12) and seat (30) enhances the annular flow pattern beneath the cutoff plug (12) at all lift positions thus reducing flow instability.

A device for controlling fluid flow. The device includes an arc generator coupled to electrodes. The electrodes are placed adjacent a fluid flowpath such that upon being energized by the arc generator, an arc filament plasma adjacent the electrodes is formed. In turn, this plasma forms a localized high temperature, high pressure perturbation in the adjacent fluid flowpath. The perturbations can be arranged to produce vortices, such as streamwise vortices, in the flowing fluid to control mixing and noise in such flows. The electrodes can further be arranged within a conduit configured to contain the flowing fluid such that when energized in a particular frequency and sequence, can excite flow instabilities in the flowing fluid. The placement of the electrodes is such that they are unobtrusive relative to the fluid flowpath being controlled.

The outer skin (100) of an aerodynamic body (40) has perforations (200) arranged in particular patterns in respective spanwise extending groups or bundles (250). Each perforation is preferably a micro-slot with a length of 100 to 3000 μm and a width of 50 to 250 μm. Air is sucked through the micro-slots from the boundary layer flowing over the outer skin, to achieve boundary layer control. In each bundle, the pattern, size, orientation, and other parameters of the micro-slots are designed to achieve mutual destructive interference of flow disturbances arising due to the suction, to minimize the excitation of flow instabilities in the boundary layer. Particularly, the spatial spectrum of the perforation pattern of a given bundle is essentially absent of significant energy at predetermined wavelengths of predetermined flow instabilities that otherwise appear in the boundary layer air flow. The aerodynamic body further includes supporting ribs (300) extending parallel to the perforation bundles (250) and a perforated inner plate (400) providing a throttling control of the suction flow through groups of the bundles.

A tubular valve housing includes a guide body for pressure fluid that is disposed between a valve body having a hollow-conical valve seat and a chamber of the valve housing, in which actuating means of the valve are received in the chamber. The guide body is penetrated by a closing body of the valve which divides the chamber from an annular conduit. The annular conduit carries the pressure fluid and communicates with the valve seat and has circumferential outlet openings of the valve housing. The guide body is braced on the valve body, with a face end contacting the valve body, and has guide conduits, fitting over an outline of the valve seat, which on the outlet side discharge into the annular conduit. The face end of the closing body, which cooperates with the valve seat, is a spherical portion that makes a transition with sharp edges to the cylindrical shaft of the closing body. With the guide body, the stream of pressure fluid emerging from the valve seat is diverted into the annular conduit, so that flow instabilities are largely without any effect on the chamber of the valve. The valve can be used in brake systems of motor vehicles.

A skimmer device for concentrating an aerosol from a flowing gas stream, having an inlet with inlet aperture and inlet raceway, an outlet with virtual impact void and collector channel, and bulk flow divertors symmetrically disposed on either side of the long axis of flow, further characterized in that the downstream walls of the bulk flow divertors are concavedly curved and reverse the direction of bulk flow. In section, the four channels or passages of the “skimmer” thus form a “crossed tee” with concavedly contoured lateral arms curving back around. The lateral flow channels are for diverting the bulk flow into exhaust chimney spaces, and the chimney spaces are positioned proximate to the inlet element and anterior to the collection channel. In operation, the bulk flow streamlines are thereby folded more than 90 degrees away from the long axis of flow on the laterally disposed concave walls of the bulk flow channels. While counterintuitive, this was found using computational fluid dynamics (CFD) and experimentation to dramatically reduce wall separation and related instabilities and to improve particle recoveries. Large two-dimensional arrays of closely stacked inlet and skimmer elements are thus achieved by fitting the chimneys into spaces between parallel inlet elements. The interlinked problems of flow instability, manufacturability of arrays, and scale-up of chimney cross-sectional area to equalize pressure differentials in the bulk flow diverter exhaust ducts, particularly in two-dimensional arrays at high throughput, are uniquely solved with this geometry.

A device for controlling fluid flow. The device includes an arc generator coupled to electrodes. The electrodes are placed adjacent a fluid flowpath such that upon being energized by the arc generator, an arc filament plasma adjacent the electrodes is formed. In turn, this plasma forms a localized high temperature, high pressure perturbation in the adjacent fluid flowpath. The perturbations can be arranged to produce vortices, such as streamwise vortices, in the flowing fluid to control mixing and noise in such flows. The electrodes can further be arranged within a conduit configured to contain the flowing fluid such that when energized in a particular frequency and sequence, can excite flow instabilities in the flowing fluid. The placement of the electrodes is such that they are unobtrusive relative to the fluid flowpath being controlled.

An ejecting flowing fluid oscillator (2) suitable for generating a fluid drop oscillating ejecting form has: an entrance (12) for pressing fluid, a dynamic nozzle (14) for constructing accelerate pressurization fluid motion, a fluid path (10) allow pressed fluid flowing between the entrance (12) and the dynamic nozzle (14), an interaction chamber (18) attached to the dynamic nozzle (14) and receiving the flowing from the nozzle, an outlet (20) ejecting fluid discharged during through the interaction chamber (18), and a device for increasing flowing instability flowing from the dynamic nozzle (14). In one first optimization embody, the device comprises a projection (4) internal extending from each side of the fluid path (10). In a second optimization embody, the device comprises a step (24), its height is the height of the dynamic nozzle (14) hoisting relative to bottom plate of the interaction chamber (18).

A solar thermal power generator includes an inclined elongated boiler tube positioned in the focus of a solar concentrator for generating steam from water. The boiler tube is connected at one end to receive water from a pressure vessel as well as connected at an opposite end to return steam back to the vessel in a fluidic circuit arrangement that stores energy in the form of heated water in the pressure vessel. An expander, condenser, and reservoir are also connected in series to respectively produce work using the steam passed either directly (above a water line in the vessel) or indirectly (below a water line in the vessel) through the pressure vessel, condense the expanded steam, and collect the condensed water. The reservoir also supplies the collected water back to the pressure vessel at the end of a diurnal cycle when the vessel is sufficiently depressurized, so that the system is reset to repeat the cycle the following day. The circuital arrangement of the boiler tube and the pressure vessel operates to dampen flow instabilities in the boiler tube, damp out the effects of solar transients, and provide thermal energy storage which enables time shifting of power generation to better align with the higher demand for energy during peak energy usage periods.

A method of using one or more microjets to create and / or control oblique shock waves. The introduction of microjet flow into a supersonic stream creates an oblique shock wave. This wave can be strengthened—by increasing microjet flow rate or the use of many microjets in an array—in order to form an oblique shock. Such an oblique shock can be used to decelerate flow in a jet aircraft engine inlet in a controlled fashion, thus increasing pressure recovery and engine efficiency while reducing flow instability. Adjusting the pressure ratio across the microjet actually alters the angle of the oblique shock. Thus, the use of microjets allows decelerating shock waves in an inlet engine to be properly positioned and controlled. Microjet arrays can also be used to ameliorate shock waves created by external aircraft surfaces, such as sensor pods and weapons. Microjets placed forward of any external protuberance can convert a single substantial shock wave into a series of much milder waves which will not produce unwanted external effects, such as strong sonic booms.

A fluidic oscillator suitable for use at colder temperatures for generating an exhaust flow in the form of an oscillating spray of fluid droplets has an inlet for pressurized fluid, a pair of power nozzles configured to accelerate the movement of the pressurized fluid, a fluid pathway that connects and allows for the flow of pressurized fluid between its inlet and the power nozzles, an interaction chamber which is attached to the nozzles and receives the flow from the nozzles, a fluid outlet from which the spray exhausts from the interaction chamber, and a means for increasing the instability of the flow from the power nozzles, with this means being situated in a location chosen from the group consisting of a location within the fluid pathway or proximate the power nozzles. In a first preferred embodiment, the flow instability generating means comprises a protrusion that extends inward from each side of the fluid pathway so as to cause a flow separation region downstream of the protrusions. In a second preferred embodiment, the flow instability generating means comprises a step in the height elevation of the floor of the power nozzles with respect to that of the interaction chamber.

A silicon mass flow sensor manufacture process that enables the backside contacts and eliminates the conventional front side wire binding process, and the assembly of such a mass flow sensor is disclosed in the present invention. The achieved assembly enhances the reliability by eliminating the binding wire exposure to the flow medium that may lead to detrimental failure due to the wire shortage or breakage while the miniature footprint could be maintained. The assembly further reduces flow instability from the flow sensor package including the bump of wire sealing. The invented mass flow sensor assembly can be a flow sensor module if the supporting sensor carrier is pre-designed with the control electronics. Without the control electronics, the said mass flow sensor assembly is easy to install into desired flow channels and connect to the external control electronics.

The device and methods described herein relate to the isothermal heat transport through an intermittent liquid supply to an evaporator device, thereby enabling high evaporative heat transfer coefficients. A liquid and vapor mixture flows through miniature and micro-channels in an evaporator and addresses flow instabilities encountered in these channels as bubbles rapidly expand. Additionally, a high percentage of the fins are exposed to vapor and limit the required charge of refrigerant within the system due to effective condensate removal in the condenser.

A device for controlling fluid flow. The device includes an arc generator coupled to electrodes. The electrodes are placed adjacent a fluid flowpath such that upon being energized by the arc generator, an arc filament plasma adjacent the electrodes is formed. In turn, this plasma forms a localized high temperature, high pressure perturbation in the adjacent fluid flowpath. The perturbations can be arranged to produce vortices, such as streamwise vortices, in the flowing fluid to control mixing and noise in such flows. The electrodes can further be arranged within a conduit configured to contain the flowing fluid such that when energized in a particular frequency and sequence, can excite flow instabilities in the flowing fluid. The placement of the electrodes is such that they are unobtrusive relative to the fluid flowpath being controlled.

The invention discloses a novel supercritical water parallel channel segment adjustable electric heating apparatus. The apparatus comprises a heating channel with an equal wall thickness, the heating channel is provided with at least three conductive copper bars, a heating module is connected between two adjacent conductive copper bars, each heating module comprises a programmable DC power source and a unidirectional diode connected with the programmable DC power source, two adjacent heating modules form one heating module group, cathodes of two unidirectional diodes of the heating module group are connected, anodes of the two unidirectional diodes are connected, and two adjacent heating modules do not flow mutually with a current loop formed by the conductive copper bars. According to the invention, segment heating of a supercritical parallel channel is realized, heating power of each segment can realize independent transient adjustment, and simulation of non-uniform heating experiment conditions in reactor thermohydraulic experimental research is satisfied. At present, mechanism experimental research is conducted on a supercritical water cooled reactor by use of the apparatus provided by the invention.

The invention belongs to an optimized design method for trimming a centrifugal pump impeller cover plate in the field of centrifugal pump research. The optimized design method includes following steps: selecting trimming parameters of the centrifugal pump impeller cover plate, determining a design range of the trimming parameters, and adopting an optimal Latin hypercube experiment design method to obtain different design schemes; simulating each scheme to acquire external characteristics and flow induced noise, building a function relation between the trimming parameters and the induced noise as well as the external characteristics according to a response face model, and applying a genetic algorithm for solving to acquire optimal optimized design parameters. On the premise that the external characteristics of a centrifugal pump are unaffected strongly, area of an impeller outlet is increased by trimming front and rear cover plates of an impeller, so that axial plane speed of the impeller outlet is reduced, pressure pulse and flow instability at volute tongue are reduced, and the objectives of reducing vibration and lowering noise are achieved.

Systems, equipment, and methods to deposit energy to modify and control air flow, lift, and drag, in relation to air vehicles, and methods for seeding flow instabilities at the leading edges of control surfaces, primarily through shockwave generation through deposition of laser energy at a distance.

Cryogenic vaporization apparatus with multiple ducts each having an inlet to receive cryogenic fluid for vaporization, and an outlet to discharge vaporized fluid to a common discharge collection manifold, there being spaces between the ducts to pass warming fluid, for warming the ducts, and flow restrictors at or proximate the inlets to produce pressure drops in the flow in the ducts, and acting to reduce flow instabilities in the manifold.

A system for controlling flow unsteadiness and noise reduction. One or more microjets are placed around the periphery of a jet nozzle in conjunction with a porous surface acting as the impingement surface. As an aircraft is taking off or landing, vertically, the microjets are activated to inject a stream of high-velocity fluid into the shear layer of the main jet at an angle from the main jet centerline. The microjets disrupt the feedback phenomenon, reducing the resonant-dominated aspect of the flow while the porous surface breaks up the coherence of the jet and reduces the broadband noise of the flow.

Natural circulation loop / system adapted to suppress flow instability inherent to fluid medium due to low driving force and non-linearity of the natural circulation process including regenerative feed back between flow rate, driving force and pressure drop by selective metallic oxide nanoparticle base fluid media such as AI2O3 dispersed in water. Advantageously even small amounts of nanoparticles dispersed in water in the natural circulation systems are found to free the loop from undesirable instability ties and importantly also surprisingly enhance the flow rate thereby facilitating avoiding premature critical heat flux, operation and control problems of such natural circulation based heat recovery. The invention thus provides simple and efficient mode of natural circulation heat recovery with flow stability and enhanced flow rate at reduced cost, favouring wide scale application and use of such system for variety of end uses / applications.

The invention discloses a method and a device for monitoring a flow instability degree of a vane pump. The method includes measuring a transient input voltage and a transient input current of a driving motor to compute transient input power of the motor; normalizing the transient input power; computing standard deviation of obtained normalized data; monitoring the flow instability degree of the pump by the aid of standard deviation values which are used as physical quantity values for measuring the current flow instability degree. The device comprises a signal acquisition module, a signal conditioning module, a signal processing module, an upper computer communication module and a human-computer interaction module; the transient voltage and the transient current of the motor can be acquired via the signal acquisition module and the signal conditioning module according to requirements of the human-computer interaction module on transmission and acquisition parameters, the transient power can be computed and normalized by the aid of the signal processing module, the standard deviation of the normalized data can be computed by the aid of the signal processing module, and results can be published via the upper computer communication module and can be displayed by the human-computer interaction module.

The invention discloses a stable control device of thermal parameters of the secondary side of a compact steam generator. The stable control device comprises a water storage tank, wherein the water storage tank passes through a high-speed centrifugal pump, a vertical preheater and a regulating pipeline in sequence through pipelines and then enters a water supply inlet of the secondary side of the steam generator, and a steam outlet of the secondary side of the steam generator passes through a condenser through a pipeline and then returns to the water storage tank. According to the stable control device, a large-flow adjustment branch and a small-flow adjustment branch are arranged on an output pipeline of the high-speed centrifugal pump, pneumatic switching valves are controlled to select according to the range of flow during actual operation, and multistage throttle hole plates are respectively arranged on each branch, so that the pressure difference of steam between an outlet of the centrifugal pump and the outlet of the secondary side of the compact steam generator is increased and is at least greater than 0.4 MPa, the phenomenon of flow instability of the secondary side of the compact steam generator is avoided, and the stable control over the water supply flow of the secondary side is realized.

A method of detecting and mitigating flow instabilities, such as slugging, in one or more hydrocarbon production wells. Real-time production data pertaining to each well is retrieved. Using the production data, patterns of flow instability are identified therein. A numerical model of transient and thermal multiphase flow in each well is generated. Well test data is retrieved from a database. The numerical model is calibrated using the well test data. Using the calibrated numerical model, a parametric study is performed to determine how input parameters affect at least one of stability and performance of the wells. Results of the parametric study are queried to determine a type of flow instability and to determine operating conditions to improve performance of the wells. An advisory is provided to a user to change operating conditions of one or more of the wells, to improve stability and / or performance of one or more of the wells.

A furnace system includes a muffle defining a furnace cavity. A lower heater is coupled to the muffle and is configured to create a hot zone within the furnace cavity having a temperature of about 1900° C. or greater. An upper muffle extension is positioned above the muffle and defines a handle cavity. A downfeed handle is positioned within the handle cavity such that a gap is defined between an outer surface of the downfeed handle and an inner surface of the upper muffle extension. An upper heater is thermally coupled to the upper muffle extension and configured to heat the gap. A gas screen is positioned in the upper muffle extension and is configured to inject a process gas into the handle cavity.

The invention discloses a nitrogen pressure stabilizing experiment device with a controllable outlet fluid temperature in a moving condition. The nitrogen pressure stabilizing experiment device comprises a closed experiment device. The experiment device is internally provided with a separator plate which divides the inner chamber of the experiment device into an upper chamber and a lower chamber. The separator plate is provided with a plurality of through holes. The top of the experiment device is provided with a nitrogen introducing pipe. The sidewall of the lower chamber of the experiment device is provided with an inlet connecting pipe and an outlet connecting pipe. A plurality of electric heating rods are mounted in the lower chamber of the experiment device. The nitrogen pressure stabilizing experiment device settles problems of natural circulation loop pressure controlling and heating experiment segment inlet fluid temperature controlling in the moving condition, and furthermore satisfies a requirement of carrying out a natural circulation loop flow unstability experiment in the moving condition. Furthermore relative to the structure in which a surge tube is connected with a voltage stabilizer, the nitrogen pressure stabilizing experiment device has advantages of simple structure, easy realization and great reduction of simulation experiment cost.