Patent Application
20160230675
In modern aircraft environments, turbine exhaust case (TEC) modules are typically air cooled using fan bypass air in a gas turbine engine. Future engines may include, or be associated with, variable and adaptive cycles where the major air streams are varied as a function of operating conditions to maximize/optimize performance and operability. There is a need to vary the flow into the TEC in these engines to provide high levels of air flow for conditions where high cooling is needed, but also provide reduced flow for other conditions since the air supplied to the TEC takes the form of a loss with respect to the engine cycle.
A valve may be used to support varying the air streams. Most valves rely on an introduction of a small control area with an abrupt area change which creates a parasitic pressure drop to reduce flow, which means losses are high in this mode. Valve methods which provide a smooth aerodynamic flow path to provide a very low pressure drop, the subject here, would benefit the engine cycle.
The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosure. The summary is not an extensive overview of the disclosure. It is neither intended to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure. The following summary merely presents some concepts of the disclosure in a simplified form as a prelude to the description below.
Aspects of the disclosure are directed to a system associated with an engine of an aircraft, comprising: a first duct configured to convey a first flow, a second duct configured to convey a second flow that corresponds to a first portion of the first flow, a third duct configured to convey a third flow that corresponds to a second portion of the first flow, and at least one valve configured to control a cross-sectional area associated with at least one of the second duct or the third duct in order to control the ratio of the first portion to the second portion. In some embodiments, the first flow is a fan flow, the second flow is a nozzle flow, and the third flow is a turbine exhaust case flow. In some embodiments, at least a portion of the second flow is used to cool a component associated with a nozzle of the aircraft. In some embodiments, at least a portion of the second flow is exhausted in order to provide forward thrust for the aircraft. In some embodiments, the at least one valve comprises an actuator and a piston. In some embodiments, the valve is coupled to an engine control system, and a state of the valve is controlled based on a command received by the valve from the engine control system. In some embodiments, the at least one valve is located within a fan duct. In some embodiments, the at least one valve is located outside of a fan duct. In some embodiments, the system is configured to provide the third flow through a plurality of turbine exhaust case vanes. In some embodiments, the system is configured to divert the third flow downstream of turbine exhaust case vanes to provide a flow going into a core.
Aspects of the disclosure are directed to a system associated with an engine of an aircraft, comprising: a first duct configured to convey a fan bypass flow, a second duct configured to convey a first portion of the fan bypass flow as at least one of a cooling nozzle flow or a thrust flow, a third duct configured to convey a second portion of the fan bypass flow as a turbine exhaust case flow, and at least one valve configured to adaptively control a cross-sectional area associated with at least one of the second duct or the third duct based on a command received by the at least one valve. In some embodiments, the third duct is configured to convey the turbine exhaust case flow to at least one strut associated with a bearing at an output of a turbine. In some embodiments, the at least one valve is located within a fan duct. In some embodiments, the at least one valve is located outside of a fan duct.
The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements.
It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities.
In accordance with various aspects of the disclosure, apparatuses, systems and methods are described for varying a flow to a turbine exhaust case (TEC) 29. The variation may be obtained without causing a large pressure loss (e.g., a loss in an amount greater than a threshold).
Aspects of the disclosure may be applied in connection with a gas turbine engine. For example,
One skilled in the art would appreciate that, in connection with the design and operation of an engine (e.g., engine 10), there may exist at least two flows. A first such flow, which may be referred to as a core flow 40, may pass through the engine hardware and be subjected to combustion in, e.g., the first engine hot section 16. A secondary flow, which may be referred to as a bypass flow 50, bypasses the engine core. A bypass ratio may be established for denoting the ratio between the bypass flow 50 and the core flow 40. The bypass ratio may be one measure of the efficiency (e.g., the fuel efficiency) of the engine 10. The bypass flow 50 typically provides cooling air 51 passing through the hot surfaces 32 of the exhaust nozzle and/or flows out of the exhaust 52 to add thrust.
TEC modules 29 associated with, e.g., the turbine 14, such as for example struts associated with bearings at the output of the turbine 14, may be cooled using air from a given flow (e.g., the bypass flow 50) passing through openings 35 in the TEC vanes 30. In some embodiments, a moving flowpath boundary may be provided to streamline a capture of a feed of air flow to the TEC, thereby changing the flow into the TEC without creating large parasitic pressure losses.
Referring to
The flow 250 may effectively be split into two flows. A first of these two flows is denoted in
A second of these two flows is denoted in
The ratio of (the splitting of the flow 250 into) the flow 260 to the flow 270 may be controlled based on a valve 280. The valve 280 is shown in
Also superimposed in
The actuator 282 may be driven by, or respond to commands from, an engine control system (not shown). The engine control system may include logic to determine a state/position for the valve 280, and hence, the actuator 282.
Regardless of the state/position of the valve 280, the channels/ducts associated with the flows 260 and 270 may include relatively smooth, aerodynamic surfaces. Accordingly, loss (e.g., a pressure drop) that is associated with the flow 260 or the flow 270 may be small/minimal.
Referring to
Referring to
Referring to
In conjunction with the systems and flows described above in connection with
As shown in
In view of the foregoing, aspects of the disclosure may be used to modulate one or more flows by controlling (e.g., modifying) a cross-section/area of one or more channels/ducts associated with the flows that are always aerodynamically smooth to reduce parasitic pressure losses. A valve may be used to provide such control. By utilizing arrangements such as those described herein, aerodynamic efficiency may be enhanced/increased.
Technical effects and benefits of this disclosure include providing a variable flow into a TEC 29 or the core 40. Such a flow may be provided with minimal, parasitic pressure losses, thereby maintaining engine performance/efficiency. Aspects of the disclosure may be applied in connection with so-called adaptive engines to facilitate a dynamic alteration of one or more engine parameters. For example, if maximum thrust is desirable then a TEC flow may be reduced, whereas if it desirable to increase cooling to the TEC then the TEC flow may be increased.
Aspects of the disclosure have been described in terms of illustrative embodiments thereof. Numerous other embodiments, modifications, and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps described in conjunction with the illustrative figures may be performed in other than the recited order, and that one or more steps illustrated may be optional in accordance with aspects of the disclosure.
