Air boost system for fuel conditioning system and operating method
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- SAFRAN SA
- Filing Date
- 2022-03-10
- Publication Date
- 2026-07-31
AI Technical Summary
Existing fuel conditioning systems for aircraft turboshaft engines using cryogenic fuel require expensive and complex compressors to convert liquid fuel to gaseous state, which are prone to breakdowns and have high energy consumption.
An air supercharging system that utilizes low and high-pressure air flows from the turboshaft engine, combined with a turbocharger, to compress and heat air for efficient conversion of liquid fuel to gaseous state, eliminating the need for bulky external compressors.
The system achieves reliable and efficient fuel conversion with reduced energy loss and system complexity, using existing turboshaft engine air flows for compression and heating, thus optimizing fuel injection into the turbine engine.
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Abstract
Description
Description Title of the invention: Air boost system for fuel conditioning system and method of use technical field
[0001] The present invention relates to the field of aircraft comprising at least one tur- A motor powered by fuel stored in a cryogenic fuel tank.
[0002] It is known to store fuel, in particular hydrogen, in the form liquid and at low temperature to limit the size and mass of the tanks of the aircraft.
[0003] In order to be able to be injected into the combustion chamber of a turboshaft engine, the Fuel must be pumped from the tank and heated to allow combustion. optimal. Such a heating stage is necessary, for example, to reduce the risk of icing of the water vapor contained in the air circulating in the tur- engine, in particular, at the level of the turbocharger's fuel injectors.
[0004] It has been proposed in the prior art to provide a conditioning system, supplied at the inlet with liquid fuel and air in order to generate at the outlet a flow of gaseous fuel. Such a conditioning system allows hydrogen to change state and become a gas, before being injected into the chamber of The combustion of the turbocharger must be consumed. The gaseous fuel flow must be pressurized to a sufficient level to be injected into the turbocharger, which requires plan for an additional compressor capable of generating very high pressures and capable of withstanding high temperatures. Such a compressor is expensive and is in- combrant.
[0005] = The invention thus aims to eliminate at least some of these drawbacks. PRESENTATION OF THE INVENTION
[0006] To this end, the invention relates to an air boosting system for a system fuel conditioning system configured to power an aircraft turboshaft engine starting from fuel from a cryogenic tank, the conditioning system being configured to be supplied at the inlet by a flow of liquid fuel from the cryogenic reservoir and by a supply airflow from a supercharging system air intake to generate, at the outlet, a flow of gaseous fuel to power the turbocharger, the air-charging system comprising: a first air intake configured to draw in a low-pressure airflow derived from the turbomotor, a second air intake configured to draw in a high-pressure airflow derived from the turbomotor, a heat exchanger configured to cool the high-pressure airflow to starting from the low-pressure airflow, a turbocharger, comprising a compressor and a turbine, connected to each other the other via a tree, the compressor is configured to compress the high-pressure airflow originating from the heat exchanger in a supply airflow intended for the conditioning system, the turbine being configured to drive the compressor in rotation by circ- culation or expansion of low pressure air flow. Thus, the air-charging system compresses a high-pressure airflow via the turbocharger, which then supplies a high-pressure, high-temperature airflow to the air conditioning system. This high-pressure airflow contributes to raising the temperature inside the air conditioning system, thereby generating a gaseous fuel flow from liquid fuel. The high pressure of the airflow allows for easy injection into the air conditioning system, particularly when mixed with a high-pressure fuel flow. Furthermore, utilizing airflow from the turbocharger and turbocharger enables optimal compression in a compact design with high reliability. Low pressure airflow refers to an airflow originating from a low pressure air intake, the airflow possibly having previously passed through a turbine. Preferably, the turboshaft engine includes an air compression zone, with the first and second air inlets fluidically connected to the compression zone. Advantageously, airflows of different pressures are available in the air compression zone. Thus, the air circulating in the compression zone is directly used by the air boost system. It is not necessary to connect the first and second air intakes to the outside of the aircraft to draw airflow. This simplifies the installation of the air supply system within fuel conditioning systems as described. According to a first embodiment of the air-boosting system, the turbocharger is dual-flow and includes a primary and a secondary flow extending around the primary flow; the heat exchanger is configured to vent the low-pressure airflow into the secondary flow of the turbocharger. Thus, the low-pressure airflow drives the turbine and compressor (which are linked) before being released into the secondary duct to contribute to propulsion. Furthermore, the high-pressure airflow powers the air conditioning system, circulating through the compressor, which is rotated by the airflow. low pressure. According to the first embodiment, the turbine is driven by the low-pressure airflow taken directly from the first air intake. According to a second embodiment of the air-supply system: the heat exchanger being configured to be fluidly connected di- directly at the first air intake, The turbine is configured to be driven by the low-pressure airflow. evacuated by the heat exchanger. Thus, the low-pressure airflow circulates directly through the heat exchanger to drive the turbine and compressor before being exhausted outside the aircraft. Additionally, the high-pressure airflow powers the air conditioning system by circulating through the compressor, which is rotated by the low-pressure airflow. Preferably, the invention relates to an assembly of a fuel conditioning system configured to supply an aircraft turboshaft engine with fuel from a cryogenic tank and an air boost system, as described above, the conditioning system being configured to be supplied at the inlet by a flow of liquid fuel from the cryogenic tank and by a supply air flow from the air boost system in order to generate, at the outlet, a flow of gaseous fuel to supply the turboshaft engine. The invention also relates to an assembly of at least one cryogenic tank, a turboshaft engine and an assembly as previously described, for supplying the turboshaft engine with fuel from the cryogenic tank. Furthermore, the invention also relates to a method of using an air boost system as described above, the method comprising steps consisting of: to cool the high-pressure airflow from the low-pressure airflow, in the heat exchanger, then compress the high-pressure airflow by driving the turbine by the low pressure airflow. According to a first embodiment of the process, implemented by the first embodiment of the air boost system, the process comprises the steps of: drive the turbine using the previously drawn low-pressure airflow through the first air intake, then inject the low-pressure airflow into the heat exchanger in order to cool the high-pressure airflow. According to a second embodiment of the process, implemented by the second In this implementation of the air-supply system, the process includes the following steps: inject the low-pressure airflow directly into the heat exchanger, in order to cool the high-pressure airflow, then drive the turbine from the low-pressure airflow discharged by the heat exchanger. PRESENTATION OF THE FIGURES The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects. Figure 1 is a schematic representation of a turboshaft engine, a fuel conditioning system and a supercharging system according to the invention connected to a cryogenic tank. Figure 2 is a schematic representation of a first embodiment of an air boosting system according to the invention. Figure 3 is a schematic representation of a second embodiment of an air boost system according to the invention. It should be noted that the figures explain the invention in detail for implementing the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION With reference to [Fig.1], an architecture is shown according to one embodiment of the invention for conducting fuel Q from a cryogenic tank RC to the combustion chamber CC of a turboshaft engine T of an aircraft. The turboshaft engine T also includes an air compression zone CA upstream of the combustion chamber CC. The compression zone CA of the turboshaft engine T includes an air inlet and an air outlet between which an airflow passes from upstream to downstream. The compression zone CA includes one or more compression stages with, for example, alternating moving blades and straightening blades. In this example, the CC combustion chamber is configured to be fueled with liquid hydrogen, but the invention applies to other types of fuel, for example, liquid methane or liquefied natural gas. According to the invention, a fuel conditioning system SC is provided, configured to supply the combustion chamber CC of the turboshaft engine T with liquid-phase fuel from the cryogenic tank RC. With reference to [Fig.1], the SC conditioning system is configured to be fed at the inlet by a flow of liquid fuel QL from the cryogenic tank RC and by a supply air flow A3 in order to generate, at the outlet, a flow of gaseous fuel QG to power the turboshaft engine T. The SC conditioning system allows to collect calories from different heat sources and / or to generate calories, for example, by combustion. The SC conditioning system is associated with an air boost system 1 configured to generate the supply airflow A3. With reference to figures 2 and 3, the air boost system | includes a first air intake El, a second air intake E2, a heat exchanger 50 and a turbocharger 60. Preferably, each air intake El, E2 is in the form of an air sampling device. The first air intake E1 is configured to draw a low-pressure airflow A1 from the turboshaft engine T. The second air intake E2 is configured to draw a high-pressure airflow A2 from the turboshaft engine T. More specifically, the first air intake E1 is connected to the air inlet of the compression zone CA. The low-pressure airflow A1 and the high-pressure airflow A2 are drawn from the compression zone CA at two axially distant locations to benefit from airflows A1 and A2 having different pressures and temperatures. For example, the second air intake E2 is connected to the air outlet of the compression zone CA. Thus, the term "low pressure" is intended to specify that the pressure is lower than that of the high-pressure airflow A2. Preferably, the pressure ratio is between 2 and 11. Referring to Figures 2 and 3, the heat exchanger 50 is connected, on one side, to the low-pressure airflow A1, A1' and, on the other side, to the high-pressure airflow A2. The heat exchanger 50 advantageously cools the high-pressure airflow A2 from the low-pressure airflow A1, A1' while maintaining a high pressure to allow optimal injection into the conditioning system SC, as will be described later. The heat exchanger 50 can implement various cooling technologies, such as finned or tube-type. The turbocharger 60 comprises a compressor 61 and a turbine 62, connected to each other via a shaft 63 so that a rotation of the compressor 61 causes a rotation of the turbine 62 and vice versa. As illustrated in Figures 2 and 3, the high-pressure airflow A2f cooled by the heat exchanger 50 is then compressed by the compressor 61 to further increase its pressure before allowing the injection of a supply airflow A3 into the conditioning system SC. The cooling of the high-pressure airflow Pressure A2 allows the use of a compressor 61 with a traditional structure to provide an airflow at the outlet with a pressure and temperature suitable for the SC air conditioning system. It is advantageously unnecessary to provide thermal reinforcement for the compressor 61. The turbine 62 is configured to drive the shaft 63, and thus the compressor 61, in rotation by circulating the low-pressure airflow A1. A turbocharger 60 is also relatively reliable and has low failure rate. Therefore, there is no energy loss. The high-pressure, high-temperature airflow A3 supplying the air conditioning system SC allows for the injection of air with the fuel Q at high pressure into said air conditioning system SC. With reference to [Fig. 2], a first embodiment of the air supercharging system 1 is shown for an aircraft comprising a turbofan engine T. A turbofan engine of this type includes a primary intake duct, comprising the air compression zone CA and the combustion chamber CC, and a secondary duct extending around the primary duct. Thus, air flows from upstream to downstream, firstly in the primary duct to be compressed and ejected after the combustion chamber CC, and secondly in the secondary duct to contribute to propulsion. The air flowing in each of the primary and secondary ducts rejoins at the outlet of the combustion chamber CC. According to the first embodiment, the low-pressure airflow A1 taken from the compression zone CA is routed to the turbine 62 to rotate it and thus drive the compressor 61. The low-pressure airflow A1', which is discharged by the turbine 62 and which has a lower pressure and temperature, then circulates in the heat exchanger 50 with the high-pressure airflow A2 as illustrated in [Fig.2]. At the outlet of the heat exchanger 50, the low-pressure airflow A1, which has cooled the high-pressure airflow A2, is then discharged to the secondary flow of the turboshaft engine T. Preferably, to allow for optimal discharge, the pressure of the low-pressure airflow A1' is higher than the pressure in the airflow flowing from upstream to downstream in the secondary flow. The low-pressure airflow A1 is thus used as a heat transfer fluid and can be reused for propulsion. As previously shown, the high-pressure airflow A2f cooled by the heat exchanger 50 is then compressed by the compressor 61, driven by the turbine 62, to further increase its pressure before allowing the injection of the supply airflow A3 into the conditioning system SC. In other words, a first low-pressure air circuit (represented by thin dashes in [Fig. 2]) connects the first intake El to the turbine 62, the turbine 62 to the heat exchanger 50, and finally the heat exchanger 50 to the secondary flow. A second The high-pressure air circuit (represented in thick dashes on [Fig.2]) connects the second outlet E2 to the heat exchanger 50, the heat exchanger 50 to the compressor 61 and finally the compressor 61 to the SC conditioning system. The low-pressure airflow A1 drives the turbine 62 and the compressor 61 before being discharged into the secondary channel. Furthermore, the high-pressure airflow A2 supplies the air conditioning system SC, circulating through the compressor 61, which is rotated by the low-pressure airflow A1. With reference to [Fig.3], a second embodiment of the air boosting system 1 is shown. According to the second embodiment, the low-pressure airflow A1 circulates successively from the first air intake El in the heat exchanger 50 and then the turbine 62. Thus, in this embodiment, the low-pressure airflow A1 participates in cooling the high-pressure airflow A2 and then drives the turbocharger 60. In other words, according to the second embodiment, a first low-pressure air circuit (represented by thin dashes on [Fig.3]) connects the first inlet E1 to the heat exchanger 50, and the heat exchanger 50 to the turbine 62. In addition, a second high-pressure air circuit (represented by thick dashes on [Fig.3]) connects the first air inlet El to the conditioning system SC in the same way as in the first embodiment. The low-pressure airflow A1 flows directly through the heat exchanger 50 to drive the turbine 62 and compressor 61 before being exhausted outside the aircraft. Additionally, the high-pressure airflow A2 supplies the air conditioning system SC by flowing through the compressor 61, which is rotated by the low-pressure airflow A1. The procedure for using an air-boosting system, as previously presented, will now be described. The process includes steps consisting of: to draw a low-pressure airflow A1 from the turboshaft engine T, to draw a high-pressure airflow A2 from the turboshaft engine T, cool the high-pressure airflow A2 from the low-pressure airflow A1, in heat exchanger 50, compress the [high-pressure air flow A2[, coming from the heat exchanger 50, into an A3 supply airflow intended for the SC conditioning system. More specifically, the high-pressure airflow A2 and the low-pressure airflow A1 are drawn from the compression zone CA. The compression of the high-pressure airflow A2f is performed by the compressor 61. According to a first embodiment, implemented by the first form of real- [Fig. 2] of the air-charging system, the process also includes steps consisting of: compress the high-pressure airflow A2f by driving the turbine 62 by the low-pressure airflow A1, then cool the high-pressure airflow A2 in the heat exchanger 50 to starting from the low pressure air flow Al' evacuated by the turbine 62. This optimizes the cooling of the high-pressure airflow A2f because the low-pressure airflow A1 is cooler after passing through the turbine 62. This configuration is advantageous for a turbofan engine because the pressure of the low-pressure airflow A1 is high enough (moderate pressure ratio) to drive the turbine 62. The heat collected in the heat exchanger 50 is not lost because the low-pressure airflow Al is reintroduced into the secondary flow of the turbofan engine T. According to a second embodiment, implemented by the second embodiment of the air boost system 1, the process comprises steps consisting of: cool the high-pressure airflow A2 directly from the airflow low pressure A1 taken from the compression zone CA, in the heat exchanger of heat 50, then compress the high-pressure airflow A2f by driving the turbine 62 by the low pressure airflow Al' evacuated by the heat exchanger 50. The low-pressure airflow A1 recovers heat in the heat exchanger 50, which is then used in the turbine 62. This advantageously reduces the flow rate of the low-pressure airflow A1. This is beneficial if the pressure of the low-pressure airflow A1 is low, particularly when the turboshaft engine is a turboprop. Thus, the air boost system allows the SC air conditioning system to be supplied by drawing air from the turbocharger without resorting to complex and cumbersome means.
Claims
Demands
1. DC air boost system (1) for air conditioning system (SC) fuel configured to power a turboshaft engine (T) aircraft using fuel (Q) from a cryogenic tank (RC), the conditioning system (SC) being configured to be supplied at the inlet by a flow of liquid fuel (QL) from the cryogenic reservoir (RC) and by a supply airflow (A3) from of an air-charging system (1), in order to generate, at the output, a gaseous fuel flow (QG) to power the turboshaft engine (T), the air boost system (1) comprising: a first air intake (El) configured to draw in a flow low-pressure air (A1) from the turboshaft engine (T), a second air intake (F2) configured to draw in a flow high-pressure air (A2) from the turboshaft engine (T), a heat exchanger (50) configured to cool the flow high-pressure air (A2) from the low-pressure airflow (A1, A1”), a turbocharger (60), comprising a compressor (61) and a turbine (62), connected to each other via a shaft (63), the compressor (61) being configured to compress the flow high-pressure air (A2[) from the heat exchanger (50) in a supply airflow (A3) intended for the system of conditioning (SC). the turbine (62) being configured to drive the compressor (61) in rotation by circulation or expansion of the low airflow pressure (A1, Al').
2. Air boost system (1) according to claim 1, in of which the turboshaft engine (T) comprises an air compression zone (CA), the first air intake (El) and the second air intake (E2) being fluidly connected to the compression zone (CA).
3. Air boost system (1) according to any one of claims 1 to 2, in which the turboshaft engine (T) is a dual-flow type and comprises a primary vein and a secondary vein extending around the vein primary, the heat exchanger (50) is configured to discharge the flow low pressure air (A1”') in the secondary flow of the turbomotor (T).
4. Supercharging system according to claim 3 in which the turbine (62) is driven directly by the low-pressure airflow taken from the first air intake (El).
5. Air boost system (1) according to any one of claims 1 to 3, in which: the heat exchanger (50) being configured to be connected fluid- directly to the first air intake (El), the turbine (62) is configured to be driven by the flow low-pressure air (A1') evacuated by the heat exchanger (50).
6. Assembly of a configured fuel conditioning (SC) system to power an aircraft turboshaft engine (T) from fuel (Q) derived from a cryogenic (RC) reservoir and a supercharging system in air (1) according to any one of claims 1 to 5, the conditioning system operation (SC) being configured to be fed into the input by a flow of liquid fuel (QL) from the cryogenic tank (RC) ct by a supply airflow (A3) from the air boost system (1) in order to generate, at the outlet, a gaseous fuel flow (QG) for power the turbomotor (T).
7. Assembly of at least one cryogenic (RC) tank, a turboshaft engine (T) and an assembly according to claim 6, to power the tur- engine (T) from fuel (Q) from the cryogenic tank (RO).
8. Method of using an air boosting system (1) according to any one of claims 1 to 5, the method comprising steps consisting of: cool the high-pressure airflow (A2) from the airflow low pressure (A1), in the heat exchanger (50), then compress the high-pressure airflow (A2f) by entrainment of the turbine (62) by the low pressure airflow (A1).
9. Method of using according to claim 8 a supercharging system air mentation (1) according to any one of claims 3 to 5, including the steps consisting of: drive the turbine (62) from the low-pressure airflow (A1) taken from the first air intake (E1), then inject the low-pressure airflow (A 1”) into the heat exchanger heat (50) in order to cool the high-pressure airflow (A2).
10. Method of using according to claim 8 a system according to the re- Demand 5, comprising the steps of: inject the low-pressure airflow (A1) taken from the first intake (El) in the heat exchanger (50), in order to cool the high-pressure airflow (A2), then drive the turbine (62) from the low-pressure airflow (A1') evacuated by the heat exchanger (50).