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Servo-controlled variable geometry ejector pump

Servo-controlled variable geometry ejector pump description/claims

This application claims the benefit of U.S. Provisional Application No. 60/859,342, filed Nov. 16, 2006.

The present invention relates to ejector pumps and, more particularly, to a variable geometry ejector pump that is configured to control downstream pressure and temperature to a variety of pressure and temperature values.

A gas turbine engine may be used to supply power to various types of vehicles and systems. For example, gas turbine engines may be used to supply propulsion power to an aircraft. Many gas turbine engines include at least three major sections, a compressor section, a combustor section, and a turbine section. The compressor section, which may include two or more compressor stages, receives a flow of intake air and raises the pressure of this air to a relatively high level. The compressed air from the compressor section then enters the combustor section, where a ring of fuel nozzles injects a steady stream of fuel. The injected fuel is ignited by a burner, which significantly increases the energy of the compressed air.

The high-energy compressed air from the combustor section then flows into and through the turbine section, causing rotationally mounted turbine blades to rotate and generate energy. The air exiting the turbine section is then exhausted from the engine. Similar to the compressor section, in a multi-spool engine the turbine section may include a plurality of turbine stages. The energy generated in each of the turbines may be used to power other portions of the engine.

In addition to providing propulsion power, a gas turbine engine may also, or instead, be used to supply either, or both, electrical and pneumatic power to the aircraft. For example, some gas turbine engines include a bleed air port on the compressor section. The bleed air port allows some of the compressed air from the compressor section to be diverted away from the combustor and turbine sections, and used for other functions such as, for example, the aircraft environmental control system, and/or cabin pressure control system.

Regardless of its particular end use, the bleed air is preferably supplied at a sufficiently high pressure to provide proper flow through the system. As noted above, bleed air is extracted after it has been compressed, which increases the load on the turbine engine. Therefore, extra fuel consumption may result, and engine performance can be degraded. The engine performance penalty may be minimized by extracting the bleed air from the lowest compressor stage (or stages) that can supply the pressure required by the downstream systems. The ideal solution for performance would be to have the capability of extracting the bleed air from the compressor stage that exactly matches the downstream systems requirements throughout the operating envelope. Most modern commercial aircraft turbine engines have on the order of 10-12 compressor stages. For practical considerations, typical commercial aircraft bleed systems are limited to two discrete bleed air ports. Moreover, many conventional bleed air systems include a heat exchanger and a fan air valve (FAV) to limit the temperature of the bleed air supplied to some end-use systems. These components can increase overall system weight and, concomitantly, overall system cost. Moreover, the heat exchanger may be mounted outside of the aircraft and in a position that increases aerodynamic drag, which can increase fuel consumption.

One solution to the above-mentioned drawbacks is disclosed in U.S. Pat. No. 6,701,715 (hereinafter “the '715 patent”), entitled “Variable Geometry Ejector for a Bleed Air System Using Integral Ejector Exit Pressure Feedback,” which is assigned to the Assignee of the instant invention. Once weakness of the solution disclosed in the '715 patent is that the ejector can only control bleed air pressure downstream of the ejector to a single pressure.

Hence, there is a need for a device that may be used in a bleed air system that can be used to more efficiently control the bleed air extracted from the engine by mixing air from separate bleed air ports, decreases overall system weight and cost and/or does not present aerodynamic drag and/or can control downstream bleed air pressure to a variety of pressures and temperatures using a variety of parameters/signals to determine the optimum outlet conditions.

In one embodiment, and by way of example only, a variable geometry ejector pump includes a primary inlet, a secondary inlet, a variable geometry ejector, an ejector valve, a mixing section, a diffuser, an actuator, and an actuator control unit. The variable geometry ejector includes at least a flow passage and an outlet nozzle. The variable geometry ejector flow passage fluidly communicates the primary fluid inlet port with the variable geometry ejector outlet nozzle. The ejector valve is disposed at least partially within the variable geometry ejector flow passage and is movable therein to control fluid flow from the primary fluid inlet through the variable geometry ejector outlet nozzle. The mixing section is in fluid communication with the secondary inlet and the variable geometry ejector outlet nozzle. The diffuser is disposed downstream of, and is in fluid communication with, the mixing section. The actuator is coupled to the ejector valve and is further coupled to receive position commands. The actuator is responsive to the position commands to controllably move the ejector valve. The actuator control mechanism is coupled to the actuator and is adapted to receive one or more control signals. The actuator control unit is operable, in response to the one or more control signals, to supply the position commands to the actuator.

The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:

FIG. 1 is a simplified representation of a bleed air system 1000 according to an exemplary embodiment of the present invention; and

FIGS. 2 and 3 are simplified representations of exemplary embodiments of variable geometry ejector pumps that may be used to implement the system of FIG. 1.

• Provisional Patent
• Utility Patent

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