System for cooling a circuit of a first fluid of a turbomachine

Abstract

A cooling system for cooling a circuit of a first fluid of a turbomachine, the cooling system including a refrigerant fluid circuit including a first heat exchanger for exchanging heat between the refrigerant fluid and air, a second heat exchanger for exchanging heat between the refrigerant fluid and the first fluid, an expander located downstream from the first heat exchanger and upstream from the second heat exchanger in the flow direction of the refrigerant fluid, and a compressor located downstream from the second heat exchanger and upstream from the first heat exchanger; the cooling system further includes a third heat exchanger of the first fluid and air type.

Claims

1. A cooling system for cooling a circuit of a first fluid of a turbomachine, the cooling system including a refrigerant fluid circuit comprising: a first heat exchanger configured to exchange heat between the refrigerant fluid and air; a second heat exchanger configured to exchange heat between the refrigerant fluid and the first fluid, the first fluid comprising oil; an expander located downstream from the first heat exchanger and upstream from the second heat exchanger in the flow direction of the refrigerant fluid; and a compressor located downstream from the second heat exchanger and upstream from the first heat exchanger; wherein the cooling system further comprises a third heat exchanger of the first fluid and air type.

2. The cooling system according to claim 1, wherein the third heat exchanger is located downstream from the refrigerant fluid circuit in the flow direction of the first fluid in the circuit.

3. The cooling system according to claim 1, wherein it further comprises actuator means configured to interrupt the operation of the refrigerant fluid circuit.

4. The cooling system according to claim 1, wherein the air comes from a secondary stream flow passage of the turbomachine.

5. The cooling system according to claim 4, wherein at least one of the first and third heat exchangers is configured to be arranged in said secondary stream flow passage of the turbomachine.

6. The cooling system according to claim 1, wherein at least one of the elements selected from the second heat exchanger, the expander, and the compressor is configured to be arranged in a nacelle of the turbomachine.

7. A turbomachine including an oil circuit and a cooling system according to claim 1, wherein the cooling system is configured to dissipate heat power generated by the oil of the oil circuit.

8. The turbomachine according to claim 7, further comprising actuator means configured to interrupt the operation of the refrigerant fluid circuit, wherein the turbomachine is configured for fitting to an airplane, and wherein the actuator means is configured to interrupt the operation of the refrigerant fluid circuit while the airplane is in a cruising type stage of flight.

9. The turbomachine according to claim 7, further comprising actuator means configured to interrupt the operation of the refrigerant fluid circuit, wherein the turbomachine is configured for fitting to an airplane, and wherein the actuator means is configured to actuate the refrigerant fluid circuit when the power of the turbomachine is greater than a predetermined threshold.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention and its advantages can be better understood on reading the following detailed description of an embodiment of the invention given by way of non-limiting example. The description refers to the accompanying sheet of figures, in which:

(2) FIG. 1 is a diagram of a cooling system of the present invention; and

(3) FIG. 2 is a diagrammatic cross-section view of a turbomachine showing the locations of the elements of the FIG. 1 cooling system.

DETAILED DESCRIPTION OF EMBODIMENTS

(4) The invention applies to dissipating any type of heat power generated in a turbomachine and that needs to be removed.

(5) The example described below relates more particularly to dissipating the heat power generated by heating the oil of an oil circuit 100 in a turbomachine 200. Nevertheless, the system of the invention could equally well apply in any other gas turbine engine to dissipating heat powers coming from the heating of various electrical components, e.g. batteries or electricity generators.

(6) In known manner, the oil circuit 100 of a turbomachine includes various pieces of equipment 102 that make use of cooling and/or lubricating oil, such as rolling bearings (in particular for turbine and compressor shafts), gearboxes (such as the accessory drive gearbox), electricity generators, etc.

(7) The oil circuit also includes recovery pumps for recirculating oil from the equipment back to an oil tank, feed pumps, and one or more filters.

(8) The turbomachine 200 also has a cooling system 2 of the present invention.

(9) As shown in FIG. 1, the cooling system 2 comprises a pump 13 for causing the oil to circulate in the circuit, and a thermodynamic device having a refrigerant fluid circuit 4.

(10) By way of example and in non-limiting manner, the refrigerant fluid of the circuit 4 is in a thermodynamic state below its critical point, however the present invention naturally also covers embodiments in which the refrigerant fluid is in a thermodynamic state above the critical point.

(11) By way of example and in non-limiting manner, the refrigerant fluid circuit 4 has a first heat exchanger 6 that forms a condenser, this first heat exchanger being configured to exchange heat between the refrigerant fluid and air; by way of example and in non-limiting manner, the air is drawn from the secondary stream flow passage of the turbomachine. The first heat exchanger 6 is thus configured to dissipate the heat power from the refrigerant fluid to air.

(12) By way of example and in non-limiting manner, the refrigerant fluid circuit 4 also has a second heat exchanger 8 that forms an evaporator that is configured to exchange heat between the refrigerant fluid and the oil in the oil circuit, by transferring heat from the hot oil in the oil circuit 100 to the refrigerant fluid.

(13) Downstream from the first heat exchanger 6 and upstream from the second heat exchanger 8, taken in the flow direction of the refrigerant fluid, the refrigerant fluid circuit 4 also includes an expander 10.

(14) Downstream from the second heat exchanger 8 and upstream from the first heat exchanger 6, still taken in the flow direction of the refrigerant fluid, the refrigerant fluid circuit 4 also has a compressor 12.

(15) In operation, when it is necessary to cool the oil of the oil circuit 100, the compressor 12 is put into operation. The second heat exchanger 8 forming an evaporator then enables the refrigerant fluid to be evaporated by taking heat from the oil. The compressor 12 serves to increase the pressure and the temperature of the refrigerant fluid in the vapor phase before it passes through the condenser-forming first heat exchanger 6 where it releases heat into air by passing from the gaseous state to the liquid state. The refrigerant fluid, now in the liquid phase, then passes through the expander 10 that has the function of reducing its pressure and lowering its temperature prior to the refrigerant fluid passing once more through the evaporator-forming second heat exchanger 8.

(16) The cooling system 2 of the present invention also has a third heat exchanger 14 of the oil and air type.

(17) By way of example and in non-limiting manner, the air for the third heat exchanger 14 is likewise drawn from the secondary stream flow passage of the turbomachine.

(18) By way of example and in non-limiting manner, the third heat exchanger 14 is located downstream from the refrigerant fluid circuit 4 in the flow direction of oil in the oil circuit 100. This arrangement is particularly advantageous and makes it possible to optimize exchanges of heat between firstly the oil in the oil circuit 100 and secondly the refrigerant fluid in the refrigerant fluid circuit 2 and the air in the third heat exchanger 14, insofar as the temperature difference between the oil and the air is greater than the temperature difference between the oil and the refrigerant fluid.

(19) Nevertheless, without going beyond the ambit of the present invention, it would be possible to devise a cooling system 2 in which the third heat exchanger 14 is located upstream from the refrigerant fluid circuit 4 in the flow direction of oil in the oil circuit 100.

(20) A bypass pipe 20 is also arranged in the oil circuit 100 in parallel with the refrigerant fluid circuit 4, having an inlet 22 arranged between the outlet from the equipment 102 of the oil circuit 100 and the inlet of the evaporating-forming second heat exchanger 8. The pipe also has an outlet 24 arranged between the outlet of the evaporator-forming second heat exchanger 8 and the inlet of the third heat exchanger 14.

(21) Closure means, such as a hydraulic valve 26, for closing the duct going to the inlet of the evaporator-forming second heat exchanger 8 are mounted between the inlet 22 of the bypass pipe 20 and the inlet of the evaporator-forming second heat exchanger 8, said closure means being configured to allow the flow of oil in the oil circuit 100 to pass either through the second heat exchanger 8 of the refrigerant fluid circuit 4 or else through the bypass pipe 20.

(22) The closure means could be mounted in the bypass pipe 20, after its inlet 22, without going beyond the ambit of the present invention.

(23) The cooling system 2 also has actuator means configured to interrupt the operation of the refrigerant fluid circuit 4. By way of example, the actuator means are thus configured to co-operate with the hydraulic valve 26 so that the oil in the oil circuit 100 flows either through the refrigerant fluid circuit 4 in order to be cooled by said refrigerant fluid prior to being cooled by the third heat exchanger 14, or else through the bypass pipe 20 so as to be cooled only by the third heat exchanger 14.

(24) Without going beyond the ambit of the present invention, it is possible to devise a cooling system 2 in which the actuator means are configured to co-operate with the compressor 12 so as to engage or interrupt the operation of the compressor 12, and consequently engage or interrupt the operation of the refrigerant fluid circuit 4. In this embodiment, it would then no longer be necessary to provide a bypass pipe 20 configured to enable the oil of the circuit to be cooled solely by the third heat exchanger 14: the oil of the oil circuit 100, then flowing through the refrigerant fluid circuit 4 while the operation of its compressor 12 is interrupted, would then no longer be cooled by said refrigerant fluid.

(25) FIG. 2 is a diagrammatic cross-section view showing the turbomachine 200 having the oil circuit 100 and the cooling system 2 of the present invention, the section being taken on a plane extending transversely relative to the longitudinal axis 201 of the turbomachine 200.

(26) The turbomachine 200 includes a gas generator 202 and a nacelle 204, both of which are centered on the longitudinal axis 201 of the turbomachine 200, with an annular passage 206 for passing the secondary flow, which is defined between the nacelle 204 and the gas generator 202.

(27) By way of example and in non-limiting manner, the air used by the cooling system 2 of the present invention, in particular by the condenser-forming first heat exchanger 6 and by the third heat exchanger 14, is air coming from the secondary stream flow passage 206 of the turbomachine 200. For this purpose, the first and third heat exchangers 6 and 14 of the cooling system 2 are positioned in the secondary stream flow passage 206, e.g. against an inside surface of the nacelle 204.

(28) In order to limit head losses in the secondary stream flow passage 206 caused by the presence of the first heat exchanger 6 while the operation of the refrigerant fluid circuit 4 is interrupted, e.g. while the airplane having the turbomachine 200 is in a cruising type stage of flight, it is possible to provide for the presence of movable cover means that are configured either to cover the first heat exchanger 6 when operation of the refrigerant fluid circuit 4 is interrupted, or else to expose the first heat exchanger 6 when the refrigerant fluid circuit 4 is in action.

(29) By way of example, the above-described actuator means that are configured to co-operate with the hydraulic valve 26 may, by way of example and in non-limiting manner, be configured to co-operate with said movable cover means.

(30) By way of example and in non-limiting manner, the second heat exchanger 8, the expander 10, and the compressor 12 are positioned directly on the nacelle 204.

(31) The third heat exchanger 14 is thus of dimensions suitable for enabling it to dissipate the heat from the oil of the oil circuit 100 while the airplane fitted with the turbomachine 100 is in a stage of cruising, without there being any need to use the refrigerant fluid circuit 4. Above the power needed during such a cruising stage, the heat pump constituted by the refrigerant fluid circuit 4 is used in order to limit the size of the third heat exchanger 14 and thus limit the head losses induced by the third heat exchanger 14 in the secondary stream flow passage 206.

(32) Although the present invention is described with reference to specific embodiments, it is clear that modifications and changes may be carried out on those embodiments without going beyond the general ambit of the invention as defined by the claims. In particular, individual characteristics of the various embodiments shown and/or mentioned may be combined in additional embodiments. Consequently, the description and the drawings should be considered in a sense that is illustrative rather than restrictive.

(33) It is also clear that all of the characteristics described with reference to a method can be transposed, singly or in combination, to a device, and vice versa, all of the characteristics described with reference to a device can be transposed, singly or in combination, to a method.