Gas turbine engine having a heat exchanger arrangement having at least one heat exchanger module overlapping another heat exchanger module

1. An engine, comprising:

an air intake arrangement configured to receive air;

a heat exchanger arrangement arranged downstream of the air intake arrangement, configured to cool the air, and comprising a plurality of heat exchanger modules; and

one or more turbomachinery components configured to receive cooled air from the heat exchanger arrangement;

wherein:

the plurality of heat exchanger modules are each arranged to be generally centred on and to be arranged along a longitudinal axis of the engine; and

at least one of the plurality of heat exchanger modules is arranged to partially overlap with at least one other one of the plurality of heat exchanger modules relative to the longitudinal axis of the engine,

wherein each of the plurality of heat exchanger modules has a respective length, and wherein at least one of the plurality of heat exchanger modules is arranged such that its respective length only partially overlaps with the respective length of at least one other one of the plurality of heat exchanger modules, relative to the longitudinal axis of the engine.

2. An engine as claimed in claim 1 , wherein a first one of the plurality of heat exchanger modules has a first length that only partially overlaps with a second length of a second one of the plurality of heat exchanger modules, and wherein the first and second lengths do not completely overlap with each other.

3. An engine as claimed in claim 2 , wherein the first and second ones of the plurality of heat exchanger modules are configured such that an outlet for heat transfer medium of the first one of the plurality of heat exchanger modules is fluidly coupled to an inlet for heat transfer medium of the second one of the plurality of heat exchanger modules.

4. An engine as claimed in claim 2 , wherein the first and second ones of the plurality of heat exchanger modules are configured such that flow of heat transfer medium in the first one of the plurality of heat exchanger modules is controllable independently of flow of heat transfer medium in the second one of the plurality of heat exchanger modules.

5. An engine as claimed in claim 1 , wherein one or more of each of the plurality of heat exchanger modules is at least partially substantially cylindrical or conical in shape.

6. An engine as claimed in claim 1 , wherein each of the plurality of heat exchanger modules has a respective inner diameter and a respective outer diameter, and wherein at least one of the plurality of heat exchanger modules has a different inner and/or outer diameter than at least one other one of the plurality of heat exchanger modules.

7. An engine as claimed in claim 1 , wherein the longitudinal axis of the engine is at least partially curved, and the plurality of heat exchanger modules are orientated along the longitudinal axis of the engine.

8. An engine as claimed in claim 1 , wherein at least one of the heat exchanger modules has a different length to at least one other one of the plurality of heat exchanger modules.

9. An engine as claimed in claim 1 , wherein each of the plurality of heat exchanger modules comprises a plurality of tubes for the flow of a heat transfer medium in heat exchange with the air.

10. An engine as claimed in claim 9 , wherein the plurality of tubes in at least one of the plurality of heat exchanger modules are spaced apart and positioned relative to one another such that said one of the plurality of heat exchanger modules is configured to provide an angle to a bulk flow of the air flowing through the heat exchanger arrangement.

11. An engine as claimed in claim 9 , wherein the one or more turbomachinery components comprises a compressor, and the engine further comprises an air-breathing combustion chamber configured to receive compressed air from the compressor and for the combustion of air and fuel;

wherein the heat exchanger arrangement is configured to be selectively operated in a first operating mode which corresponds with a first operating flight speed of the engine, and a second operating mode which corresponds with a second operating flight speed of the engine that is lower than the first operating flight speed of the engine;

wherein in the first operating mode of the heat exchanger arrangement, the heat transfer medium is configured to heat the fuel before it is delivered to the air-breathing combustion chamber; and

wherein in the second operating mode of the heat exchanger arrangement, the heat transfer medium is configured to cool the fuel before it is delivered to the air-breathing combustion chamber.

12. An engine as claimed in claim 1 , wherein the engine further comprises a bypass arrangement configured to prevent the air received by the air intake arrangement from flowing through at least one of the plurality of heat exchanger modules.

13. An engine as claimed in claim 1 , wherein each of the plurality of heat exchanger modules is at least partially substantially conical in shape.

14. An engine as claimed in claim 13 , wherein the plurality of heat exchanger modules are arranged in series or in parallel relative to a longitudinal axis of the engine.

15. An engine as claimed in claim 13 , wherein each of the plurality of heat exchanger modules comprises a plurality of tubes for the flow of a heat transfer medium in heat exchange with the air.

16. An engine as claimed in claim 15 , wherein the plurality of tubes in at least one of the plurality of heat exchanger modules are spaced apart and positioned relative to one another such that said one of the plurality of heat exchanger modules is configured to provide an angle to a bulk flow of the air flowing through the heat exchanger arrangement.

17. An engine as claimed in claim 13 , wherein the engine further comprises a bypass arrangement configured to prevent the air received by the air intake arrangement from flowing through at least one of the plurality of heat exchanger modules.

18. An engine as claimed in claim 1 , further comprising:

a fuel tank configured to store a fuel for being supplied to an air-breathing combustion chamber; and

a compressor arranged downstream of the heat exchanger arrangement and configured to supply compressed air to the air-breathing combustion chamber for the combustion of the air and the fuel;

wherein the heat exchanger arrangement is configured to cool the air by providing for heat exchange between the air and a heat transfer medium;

wherein the heat exchanger arrangement is configured to be selectively operated in a first operating mode which corresponds with a first operating flight speed of the engine, and a second operating mode which corresponds with a second operating flight speed of the engine that is lower than the first operating flight speed of the engine;

wherein in the first operating mode of the heat exchanger arrangement, the heat transfer medium is configured to heat the fuel before the fuel is delivered to the air-breathing combustion chamber; and

wherein in the second operating mode of the heat exchanger arrangement, the heat transfer medium is configured to cool the fuel before the fuel is delivered to the air-breathing combustion chamber.

19. A method of operating an engine as claimed in claim 18 , the method comprising:

suppling air to the air intake arrangement;

causing the air to flow through the air intake arrangement, the heat exchanger arrangement, the compressor and the air-breathing combustion chamber;

supplying heat transfer medium to the heat exchanger arrangement;

causing the heat transfer medium to flow through the heat exchanger arrangement;

supplying fuel to the fuel tank; and

causing the fuel to flow from the fuel tank to the air-breathing combustion chamber;

wherein the method further comprises operating the heat exchanger arrangement in the first operating mode when the engine is operating at the first operating flight speed, and operating the heat exchanger arrangement in the second operating mode when the engine is operating at the second operating flight speed.

20. An aircraft, flying machine or aerospace vehicle comprising an engine as claimed in claim 1 .