SWIRL REDUCING GAS TURBINE ENGINE RECUPERATOR
A gas turbine engine recuperator recuperator including exhaust passages providing fluid flow communication between an exhaust inlet and an exhaust outlet, the exhaust inlet being oriented to receive exhaust flow from a turbine of the engine and the exhaust outlet being oriented to deliver the exhaust flow to atmosphere, the exhaust passages having an arcuate profile in a plane perpendicular to a central axis of the recuperator to reduce a swirl of the exhaust flow. Air passages are in heat exchange relationship with the exhaust passages and providing fluid flow communication between an air inlet and an air outlet, design to sealingly respective plenum of the gas turbine engine.
This application is a divisional of U.S. application Ser. No. 13/036,463 filed Feb. 28, 2011, the entire contents of which are incorporated by reference herein.
TECHNICAL FIELDThe application relates generally to a recuperator for a gas turbine engine and, more particularly, to such a recuperator allowing for reduction of the swirl in the exhaust flow.
BACKGROUND OF THE ARTGas turbine engines may include a recuperator, which is a heat exchanger using hot exhaust gas from the engine to heat the compressed air exiting the compressor prior to circulation of the compressed air to the combustion chamber. Preheating the compressed air usually improves fuel efficiency of the engine. In addition, the recuperator reduces the heat of exhaust gas, which helps minimize the infrared signature of the aircraft.
Axial or radial air entry swirlers are generally used during combustion in order to stabilize the flame and promote mixing. However, this usually results in a relatively important swirl component in the exhaust flow exiting the turbine section. Typically, deswirling vanes are provided between the turbine section and the exhaust mixer of the engine to reduce the swirl of the exhaust flow, such as to convert the kinetic energy of the flow into increased thrust.
SUMMARYIn one aspect, there is provided a recuperator configured to extend within an exhaust duct of a gas turbine engine, the recuperator comprising exhaust passages providing fluid flow communication between an exhaust inlet and an exhaust outlet, the exhaust inlet being oriented to receive exhaust flow from a turbine of the engine and the exhaust outlet being oriented to deliver the exhaust flow to atmosphere, the exhaust passages having an arcuate profile in a plane perpendicular to a central axis of the recuperator to reduce a swirl of the exhaust flow, air passages in heat exchange relationship with the exhaust passages and providing fluid flow communication between an air inlet and an air outlet, an inlet connection member defining the air inlet and being designed to sealingly engage a first plenum in fluid flow communication with a compressor discharge of the gas turbine engine, and an outlet connection member defining the air outlet and being designed to sealingly engage a second plenum containing a compressor of the gas turbine engine.
In another aspect, there is provided a gas turbine engine comprising a compressor section having a discharge in fluid flow communication with a first plenum, a combustor contained in a second plenum, a turbine section in fluid flow communication with the combustor, an exhaust duct in fluid flow communication with the turbine section, and a recuperator located in the exhaust duct, the recuperator defining: exhaust passages providing fluid flow communication between an exhaust inlet and an exhaust outlet, the exhaust inlet and exhaust outlet extending across the exhaust duct with the exhaust inlet being in fluid flow communication with the turbine section, the exhaust passages having an arcuate profile in a plane perpendicular to a central axis of the recuperator to reduce a swirl of the exhaust flow, air passages in heat exchange relationship with the exhaust passages and providing fluid flow communication between an air inlet and an air outlet, an inlet connection member defining the air inlet and sealingly engaging the first plenum to receive pressurized air from the compressor, and an outlet connection member defining the air outlet and sealingly engaging the second plenum containing the combustor.
In a further aspect, there is provided a method of deswirling and cooling an exhaust flow in an exhaust duct of a gas turbine engine, comprising circulating the exhaust flow from a turbine section of the gas turbine engine to a recuperator extending within the exhaust duct, circulating air discharged from a compressor section to a combustor of the gas turbine engine through air passages of the recuperator, and deswirling and diffusing the exhaust flow by circulating the exhaust flow through exhaust passages of the recuperator having an arcuate profile in a plane perpendicular.
Reference is now made to the accompanying figures in which:
Although illustrated as a turbofan engine, the gas turbine engine 10 may alternately be another type of engine, for example a turboshaft engine, also generally comprising in serial flow communication a compressor section, a combustor, and a turbine section, and a propeller shaft supporting a propeller and rotated by a low pressure portion of the turbine section through a reduction gearbox.
Referring to
A recuperator 30 extends across the exhaust duct 24, such that the exhaust gas from the turbine section 18 circulates therethrough. The recuperator 30 also provides the fluid flow communication between the combustor plenum 26 and the compressor plenum 28, as will be further detailed below.
Referring to
Referring particularly to
The exhaust fluid passages 42 communicate with a same exhaust inlet 50 defined by the radially inward end of the segment 32 and with a same exhaust outlet 52 defined by the radially outward end of the segment 32. The exhaust inlet and outlet 50, 52 extend across the exhaust duct 24, with the exhaust inlet 50 located in proximity of the turbine section 18.
Referring to
Referring back to
Alternately, the inlet connection member 58 may define a rigid connection with the compressor plenum 28, with the outlet connection member 74 defining a floating connection with the combustor plenum 26.
Referring back to
In a particular embodiment, the exhaust passages 42 have a flaring shape, i.e. the cross-sectional area of each exhaust passage 42 increases from the exhaust inlet 50 to the exhaust outlet 52, such as to diffuse the exhaust flow. The exhaust inlet 50 thus has a smaller cross-sectional area than that of the exhaust outlet 52. Referring particularly to
In the alternate embodiment shown in
In a particular embodiment, the recuperator 30 also reduces the swirl of the exhaust flow. As can be seen from
Referring now to
The recuperator 130 extends within the exhaust duct 24 closer to the turbine section 18 than the previously described embodiment. Each segment 132 includes an exhaust inlet 150 defined by a radially extending end of the segment 132 located in proximity of the turbine section 18 and in communication with the exhaust passages 142. The exhaust inlet 150 is oriented such that the exhaust gas flows axially or approximately axially therethrough. Each segment 132 also includes an exhaust outlet 152 in communication with exhaust passages 142, and oriented such that the exhaust gas flows outwardly radially or approximately outwardly radially therethrough.
The air passages 140 communicate with a same air inlet 156 defined at one end thereof and with a same air outlet 172 defined at the opposed end thereof. The air inlet 156 is defined by an inlet connection member 158 which is designed to sealingly engage the compressor plenum 28 for circulating the compressed air. The air inlet 156 is oriented such that the compressed air flows axially or approximately axially therethrough. The inlet connection member 158 includes a support 164 surrounding the inlet 156 which is rigidly connected to the compressor plenum 28, for example through an appropriate type of fasteners with a compressible seal ring or a gasket (not shown) therebetween. The inlet connection member 158 thus defines a rigid connection with the compressor plenum 28.
The air outlet 172 is defined by an outlet connection member 174 which is designed to sealingly engage the combustor plenum 26 for delivering the heated compressed air to the combustor 16. The air outlet 172 is oriented such that the heated compressed air flows radially outwardly or approximately radially outwardly therethrough. The outlet connection member 174 includes a duct 176 which is engaged in a corresponding opening of the combustor plenum 26. Referring to
As can be seen in
In a particular embodiment, the recuperator 130 also reduces the swirl of the exhaust flow. As can be seen from
In the above described embodiments, each segment 32, 132 of the recuperator 30, 130 is only connected to the engine 10 through the inlet and outlet connection members 58, 158, 74, 174, and the segments 32, 132 are independent from each other. Since one of these connection members defines a floating connection, some relative movement is allowed between each segment 32, 132 of the recuperator 30, 130 and the remainder of the gas turbine engine 10, such as to accommodate some amount of thermal expansion without impeding the seal of the connections.
The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.
Claims
1. A method of deswirling and cooling an exhaust flow in an exhaust duct of a gas turbine engine, comprising:
- circulating the exhaust flow from a turbine section of the gas turbine engine to a recuperator extending within the exhaust duct;
- circulating air discharged from a compressor section to a combustor of the gas turbine engine through air passages of the recuperator; and
- deswirling and diffusing the exhaust flow by circulating the exhaust flow through exhaust passages of the recuperator having an arcuate profile in a plane perpendicular to a central axis of the recuperator and in heat exchange relationship with the air passages.
2. The method as defined in claim 1, wherein circulating the exhaust flow from the turbine section to the recuperator includes circulating the exhaust flow through passages defined by circumferential splitters located in the exhaust duct and supported by radially extending struts having an asymmetrical airfoil shape twisted to reduce the swirl of the exhaust flow.
3. The method as defined in claim 2, further comprising reducing the swirl of the exhaust flow with the splitters being curved in the plane perpendicular to the central axis of the recuperator.
4. The method as defined in claim 2, wherein the exhaust flow circulates through the passages defined by the circumferential splitters along a path oriented progressively from an axial or substantially axial direction to a radial or substantially radial direction.
5. The method as defined in claim 2, wherein the splitters form part of the recuperator.
6. The method as defined in claim 1, wherein circulating the exhaust flow through the exhaust passages of the recuperator includes circulating the flow from an exhaust inlet to an exhaust outlet of the exhaust passages, and wherein the arcuate profile defines a curve having a concave side facing a same circumferential direction from adjacent an exhaust inlet to adjacent the exhaust outlet, the arcuate profile directing the exhaust flow in an arcuate direction from the exhaust inlet to the exhaust outlet.
7. The method as defined in claim 1, wherein the air and exhaust passages are relatively oriented such as to define a mixed counter flow and double pass cross flow heat exchanger.
8. The method as defined in claim 1, wherein the recuperator comprises a plurality of identical and independent arcuate segments.
9. The method as defined in claim 1, wherein the recuperator has a shape substantially conforming to that of the exhaust duct.
Type: Application
Filed: Aug 9, 2017
Publication Date: Dec 28, 2017
Inventors: Andreas ELEFTHERIOU (Woodbridge), David MENHEERE (Georgetown), Daniel ALECU (Toronto), Darius Jehangir KARANJIA (Mississauga), Daniel VAN DEN ENDE (Mississauga)
Application Number: 15/673,056