HYDROGEN GAS TURBINE

Abstract

A gas turbine main engine powered by a fuel, includes a combustion chamber configured to receive fuel through at least one injector, a turbopump including a pump, an inlet for introducing the fuel in a first state into the pump, a turbine, a turbine outlet for discharging the fuel in a second state, the outlet being fluidically connected to the combustion chamber through the injector, and a clutch further including a shaft, a heat exchanger comprising an inlet, fluidically connected to the turbopump pump, and an outlet, fluidically connected to the turbopump turbine. The heat exchanger heats fuel in the first state from the pump into fuel in the second state for the turbine. The engine further includes a bypass system fluidically connected with the heat exchanger outlet and the turbopump outlet. The clutch shaft is coupled both to a main engine accessory gearbox and to a turbopump shaft.

Claims

1. A gas turbine main engine powered by a fuel, comprising: a combustion chamber configured to receive fuel through at least one injector, a turbopump comprising: a pump, an inlet for introducing the fuel in a first state into the pump, a turbine, an outlet for discharging the fuel in a second state from the turbine, the outlet being fluidically connected to the combustion chamber through the injector, and a clutch further comprising a shaft, a heat exchanger comprising: an inlet, fluidically connected to the pump of the turbopump, and an outlet, fluidically connected to the turbine of the turbopump, wherein the heat exchanger is configured for heating fuel in the first state from the pump into fuel in the second state for the turbine, wherein the engine further comprises a bypass system fluidically connected with the outlet of the heat exchanger and the outlet of the turbopump, and wherein the shaft of the clutch is coupled both to a main engine accessory gearbox and to a shaft of the turbopump.

2. The gas turbine main engine according to claim 1, wherein the fuel in a first state comprises liquid fuel.

3. The gas turbine main engine according to claim 1, wherein the fuel in a second state comprises conditioned fuel.

4. The gas turbine main engine according to claim 1 further comprising an exhaust port, the heat exchanger being located at said exhaust port.

5. The gas turbine main engine according to claim 1, further comprising an exchanger bypass, located between the inlet and the outlet of the heat exchanger.

6. The gas turbine main engine according to claim 1, further comprising pressure regulating means configured to regulate a pressure of the fuel in the second state before entering into the combustion chamber through the at least one injector.

7. The gas turbine main engine according to claim 6, wherein the pressure regulating means comprise at least one of a pressure regulator, a throttling element or a valve.

8. The gas turbine main engine according to claim 6, wherein the pressure regulating means comprise a flow control valve and a pressure regulator.

9. The gas turbine main engine according to claim 6, wherein the pressure regulating means further comprise controlling means.

10. The gas turbine main engine according to claim 1, wherein the shaft of the clutch is coupled with a shaft of the main engine accessory gearbox.

11. The gas turbine main engine according to claim 1, wherein the heat exchanger is configured, in an operative manner, to modify at least one of a temperature or pressure of the fuel such that a phase transition from the first state to the second state is performed on the fuel.

12. The gas turbine main engine according to claim 1, wherein the phase transition from the first state to the second state comprises to a supercritical state.

13. The gas turbine main engine according to claim 1, wherein the fuel comprises hydrogen.

14. The gas turbine main engine according to claim 1, wherein the turbine further comprises a plurality of nozzles configured to be oriented according to requirements of power of the main engine.

15. The gas turbine main engine according to claim 1, wherein the bypass system is configured to regulate the flow of fuel in the second state according to requirements of power of the main engine.

16. An aircraft comprising a gas turbine main engine according to claim 1.

17. A method for providing fuel in a second state, to a gas turbine main engine according to claim 1, comprising the following steps: providing a fuel in a first state, to the pump of the turbopump and pumping said fuel in the first state to the heat exchanger, through the inlet of the heat exchanger, heating the fuel in the first state, such that a phase transition from the first state to the second state, is performed, obtaining a conditioned fuel, delivering the fuel in the second state, conditioned fuel, from the outlet of the heat exchanger to at least one of: the turbine or, the outlet of the turbine through the bypass system, performing a pressure regulation of the fuel in the second state by the pressure regulating means, injecting the fuel in the second state from the outlet of the turbine to the combustion chamber through the at least one injector.

18. The method according to claim 17, wherein the fuel in a first state comprises a liquid fuel.

19. The method according to claim 17, wherein the phase transition from the first state to the second state is to a supercritical state.

20. The method for providing fuel in a second state to a gas turbine main engine according to claim 17, wherein during a start of the main engine, the providing and heating steps are avoided by pumping the fuel in the first state directly to the outlet of the heat exchanger by means of the exchanger bypass.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0119] These and other characteristics and advantages of the invention will become clearly understood in view of the detailed description of the invention which becomes apparent from a preferred embodiment of the invention, given just as an example and not being limited thereto, with reference to the drawings.

[0120] FIG. 1 shows a schematic view of an example of a gas turbine main engine.

[0121] FIG. 2 shows a general view of an additional example of a gas turbine main engine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0122] FIG. 1 shows a schematic view of an example of a gas turbine main engine (1).

[0123] In particular, the engine (1) is a combustion engine having a combustion chamber (2) wherein the fuel is injected by means of an injector (2.1) for its ignition.

[0124] The exhaust gases from combustion chamber (2), once the fuel has been combusted inside the combustion chamber (2), are exhausted to the environment through an exhaust port. Such exhaust port is located at the exhaust section (not shown), thus located after the turbine (3.2), which is located immediately after the combustion chamber (2).

[0125] Immediately after such exhaust port, a heat exchanger (4) is located. Fuel in the first state passes through the heat exchanger (4), wherein a change of phase to the second state is achieved. The walls of the heat exchanger (4) are in thermal contact with the exhaust gases exiting from the combustion chamber (2) through the exhaust port, and the high temperatures of the exhaust gases provides a heat exchange with the fuel in the first state present inside the heat exchanger. Therefore, the fuel of the gas turbine main engine (1), which in this case is hydrogen, harvests heat from the exhaust gases and is thus heated up to the conditions in which it passes from the first to the second state.

[0126] The fuel, particularly hydrogen in a liquid state, is introduced in the pump (3.1) of a turbopump (3), which is fluidically connected with the combustion chamber (2).

[0127] Particularly, the liquid fuel (LF) is introduced in the pump (3.1) and driven to the heat exchanger (4), introducing the liquid fuel (LF) inside through the inlet (4.1) of the heat exchanger (4).

[0128] The liquid fuel (LF) is heated inside the heat exchanger (4) and leaves the heat exchanger (4) through its outlet (4.2) in a conditioned state, that is to say, as a conditioned fuel (CF) in a supercritical state, arriving at the turbine (3.2) of the turbopump (3).

[0129] The conditioned fuel (CF) exits the turbine (3.2) of the turbopump (3) through an outlet (3.5) of the turbopump (3), and is directed to the combustion chamber (2), entering the combustion chamber (2) through an injector (2.1) in the adequate conditions for its ignition, thus supplying the proper power to the engine (1).

[0130] The flow of conditioned fuel (CF) which arrives to the turbine (3.2) is regulated by means of the bypass system (5), which controls the flow of conditioned fuel (CF) that exits the heat exchanger (4) and enters the combustion chamber (2).

[0131] The path followed by the hydrogen, both in its liquid and conditioned states, is shown in present FIG. 1.

[0132] In order to regulate and control the fuel flow, both in liquid and conditioned state, additional elements and systems can be introduced in the gas turbine main engine (1) shown in FIG. 1.

[0133] Thus, FIG. 2 shows another example of gas turbine main engine (1), wherein the totality of the elements present in FIG. 1 are also shown.

[0134] Additionally, pressure regulating means (7) have been introduced in the gas turbine main engine (1), located immediately before the injector (2.1).

[0135] That is, the conditioned fuel (CF) exits the turbine (3.2) through the outlet (3.5) and is directed to the pressure regulating means (7). The flow of conditioned fuel (CF) which comes directly from the bypass system (5) to the outlet (3.5) of the turbopump (3) is also directed, as a unique flow of conditioned fuel (CF) to the pressure regulating means (7), which adapt the pressure of the fuel to the requirements of the engine (1), in order to provide a better injection of the conditioned fuel (CF) inside the combustion chamber (2). Additionally, the turbine (3.2) comprises a plurality of nozzles (3.2.1) which are configured to be oriented according to the requirements of power of the main engine (1).

[0136] Moreover, an exchanger bypass (6) is shown between the inlet (4.1) and the outlet of the heat exchanger (4). Particularly, the exchanger bypass (6) is a modulating bypass valve, which inlet is located between the outlet (3.1.1) of the pump (3.1) and the inlet (4.1) of the heat exchanger (4).

[0137] The mentioned exchanger bypass (6) controls the flow of liquid fuel (LF) from the pump (3.1) to the heat exchanger (4.1), regulating the entry flow of liquid fuel inside the heat exchanger (4).

[0138] Thus, the exchanger bypass (6) allows a portion of the flow of liquid fuel to pass through the heat exchanger (4), thus receiving heat from it (particularly, heat exchanged from the exhaust gases), and changing its phase from liquid to supercritical state. The remaining portion of the liquid fuel (LF) coming from the pump (3.1) bypasses the heat exchanger (4) through the exchanger bypass (6), being directly diverted from the pump (3.1) either to the bypass system (5), which in turn diverts it to the outlet (3.5) of the turbopump (3), or to the inlet (3.2.2) of the turbine (3.2).

[0139] Although not shown in FIGS. 1 and 2, the bypass system (5) is configured by means of a flow control valve and a pressure regulator, whereas the exchanger bypass (6) is configured by a modulating bypass valve.

[0140] Although the mentioned elements are shown in the present combination in FIGS. 1 and 2, it is to be noted that any combination of the present referred elements is possible, wherein, for example, a combination of the exchanger bypass (6) with the elements and configuration shown in FIG. 1 is possible, without introducing the pressure regulating means (7) and vice versa. That is, every referred element and system hereby forming part of any embodiment of the gas turbine main engine (1) is usable in any combination thereof.

Example 1: State and Temperature of the Hydrogen Fuel

[0141] Regarding any of the aforementioned configurations of a gas turbine main engine (1), the systems are configured in order to fulfill the requirements of the mentioned engine (1).

[0142] According to such a configuration and the requirements to be fulfilled, the heat exchanger (4) can be sized in order to provide a preferred configuration of the system.

[0143] Regarding the embodiment shown in FIG. 2, the heat exchanger (4) is sized for this application, providing a temperature of the conditioned hydrogen of 61K (gaseous hydrogen) at the outlet of the heat exchanger of the flow of fuel and 45K at the outlet of the turbine (3.2) of the turbopump (3) of the gaseous flow of hydrogen, the gaseous hydrogen being at a pressure of 4.23 MPa, which implies that the hydrogen is at a supercritical state at the turbine outlet. At this level of pressure (4.23 MPa) the temperature at which the hydrogen is in liquid state is around 33K, so this means that the hydrogen in supercritical state is 12K above its liquid temperature. The shaft power at the turbopump (3) for this operating condition is 326 KW, the turbine pressure ratio (from nozzle to rotor) is 1.66.

[0144] Special importance is drawn to target temperatures above the gas state of the fuel, in this case hydrogen, for its injection in the combustion chamber (2) of the engine (1), in order to improve the combustion process efficiency, as well as to provide a trade-off between supercritical injection of the hydrogen and gas injection of the hydrogen which can be made to choose the right temperature range of the fuel. That is, a trade-off between different temperature levels of the fuel is performed. Particularly, it has been proven that temperatures over 40K for the hydrogen at the outlet of the turbine (3.2) of the turbopump (3) provides an adequate ignition and provision of power to the engine (1).

[0145] For the hydrogen fuel to be in the corresponding temperature levels for a gas or supercritical state of such fuel at the injector (2.1), the heat exchanger (4) can also be sized to provide an increased power transfer to the fuel, by means of a coil cross section shape that increases the heat transfer per unit of length, additional coils, or other types of heat exchangers.

[0146] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.