Hybrid fuel supply system and experimental methods for extreme environmental testing of sustainable aviation fuel

Abstract

This invention discloses a fuel mixing system and experimental method for extreme environment testing of sustainable aviation fuel. The fuel mixing system includes a fuel mixing system, an extreme environment simulation system, an aircraft engine / combustion experimental system, and a fuel supply and return flow regulation system. The fuel mixing system is used to uniformly mix different types of aviation fuel to form a mixed fuel. The extreme environment simulation system is connected to the fuel mixing system and is used to simulate various extreme environments during the delivery of the mixed fuel. The fuel supply and return flow regulation system is connected to the extreme environment simulation system, the aircraft engine / combustion experimental system, and the fuel mixing system, respectively, and is used to regulate the mixed fuel supplied to the aircraft engine / combustion experimental system and return excess fuel to the fuel mixing system in an adjustable flow manner. This invention can test aviation fuel containing sustainable aviation fuel under various extreme environments.

Description

Technical Field

[0001] This invention relates to the field of sustainable aviation fuel application technology, and in particular to a hybrid fuel supply system and experimental method for extreme environment testing of sustainable aviation fuel. Background Technology

[0002] Sustainable aviation fuel (SAF) refers to aviation fuel derived from renewable materials, such as biofuel, which can reduce carbon emissions by 60-80% over its entire life cycle compared to traditional fuels. The use of SAF in aircraft engines requires a rigorous airworthiness certification process. Before the large-scale use of SAF in civil aircraft, testing and preliminary research on various characteristics of SAF (such as fuel supply and combustion) in laboratories will provide crucial data support for its application. However, currently, there are very few dedicated experimental systems for SAF testing.

[0003] Currently, SAF (Self-Produced Fuel) has a wide range of raw material sources, such as waste cooking oil, agricultural and forestry waste, microalgae, and lignocellulose. There are also many preparation processes, such as Fischer-Tropsch synthesis, hydrogenation, and biomass pyrolysis. Different raw materials and processes result in different physicochemical properties of SAF, such as viscosity, density, and low calorific value, and these properties may differ significantly from traditional jet fuel. Furthermore, the lack of aromatic hydrocarbons in SAF leads to fuel leaks when used in aircraft fuel supply systems. The difference in freezing points necessitates the addition of anti-gelling agents to some SAFs. Therefore, SAF cannot completely replace traditional jet fuel from the outset. Instead, it is initially used in small proportions blended with jet fuel, gradually increasing the blending ratio while adapting to changes in fuel supply systems to gradually increase the substitution rate. Moreover, the high cost of raw materials and preparation for SAF currently results in severely insufficient production. It is expected that in the future, SAF mixtures with different physicochemical properties will be used initially. Therefore, the development of testing systems for SAF fuel supply systems, especially testing systems for SAF mixed fuel supply systems, is crucial.

[0004] Aircraft engine fuel supply systems may encounter many extreme environments at high altitudes, such as: 1) the low temperatures at high altitudes cause the fuel supply system to cool and wax to form inside the fuel; 2) some fuel supply lines may be affected by high temperatures due to engine heat transfer, causing fuel to coke in the fuel lines; 3) components of the fuel supply system may be affected by oxidation, moisture, corrosion, or the ingress of sand and dust particles, potentially leading to the introduction of tiny foreign objects (foreign matter addition); 4) the engine may sometimes vibrate to a certain amplitude, causing the fuel lines and other components of the fuel supply system to move with a certain amplitude; 5) during engine afterburner (acceleration) and deceleration, the fuel supply system must respond transiently to changes in fuel supply. Before obtaining SAF airworthiness certification, it is essential to verify the characteristics and performance of SAF fuel supply under extreme environments, especially the characteristics of hybrid SAF. However, there is currently limited research on SAF fuel supply devices and extreme environment testing equipment. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of this invention is to provide a mixed fuel supply system for extreme environment testing of sustainable aviation fuel, which can test uniformly mixed aviation fuel containing sustainable aviation fuel under various extreme environments, and can also compensate for fuel supply deviations caused by changes in fuel density and viscosity.

[0006] According to a first aspect of the present invention, a hybrid fuel supply system for sustainable aviation fuel extreme environment testing includes a fuel supply mixing system, an extreme environment simulation system, an aircraft engine / combustion experimental system, and a fuel supply and return flow regulation system.

[0007] The fuel supply and mixing system is used to uniformly mix different aviation fuels to form a mixed fuel; the extreme environment simulation system is connected to the fuel supply and mixing system, and is used to receive and deliver the mixed fuel output by the fuel supply and mixing system, and to simulate various extreme environments when delivering the mixed fuel;

[0008] The fuel supply and return flow regulation system is connected to the extreme environment simulation system, the aero-engine / combustion test system, and the fuel supply and mixing system, respectively. The fuel supply and return flow regulation system is used to receive the mixed fuel output from the extreme environment simulation system, regulate the flow rate of the mixed fuel, supply mixed fuel to the aero-engine / combustion test system to enable its operation, and return the mixed fuel discharged from the aero-engine / combustion test system to the fuel supply and mixing system in an adjustable flow rate. The fuel supply and return flow regulation system is also used to receive the mixed fuel output from the extreme environment simulation system, regulate the flow rate of the mixed fuel, and return a portion of the excess mixed fuel that does not enter the aero-engine / combustion test system to the fuel supply and mixing system in an adjustable flow rate.

[0009] The fuel supply system for extreme environment testing of sustainable aviation fuel according to the first aspect of the present invention has the following advantages: First, the present invention uses a fuel supply and mixing system to uniformly mix different aviation fuels, thereby obtaining a fuel mixture with high mixing uniformity. Second, the present invention uses an extreme environment simulation system to simulate various extreme environments, enabling comprehensive experimental evaluation of fuel mixtures containing sustainable aviation fuel under extreme conditions. Third, the present invention uses a fuel supply and return flow regulation system, which, on the one hand, can simulate a transitional environment to test the fuel mixture and fuel supply system under such extreme conditions; on the other hand, it can be used for fuel characteristic compensation to ensure accurate control of fuel supply flow; furthermore, it can discharge the fuel mixture from the fuel supply system for extreme environment testing of sustainable aviation fuel without passing through the combustion chamber of the aircraft engine or combustion test system, as needed. In summary, the present invention can conduct experimental tests under various extreme environments to study and verify the characteristics and performance of fuel mixtures containing sustainable aviation fuel and the fuel supply system for extreme environment testing of sustainable aviation fuel under extreme conditions.

[0010] According to some embodiments of the first aspect of the present invention, the fuel supply and mixing system includes multiple fuel supply branches, a mixing chamber, and a pressure regulating pump; each of the multiple fuel supply branches is connected to the mixing chamber for injecting different types of aviation fuel into the mixing chamber; the mixing chamber is used to uniformly mix the injected different types of aviation fuel to form a mixed oil; the mixing chamber is connected to the extreme environment simulation system through a first delivery pipeline, and the pressure regulating pump is disposed on the first delivery pipeline for adjusting the pressure of delivering the mixed oil in the mixing chamber to the extreme environment simulation system.

[0011] According to some embodiments of the first aspect of the present invention, the oil supply mixing system further includes an additive branch, one end of which is connected to the first delivery pipeline and located between the pressure regulating pump and the extreme environment simulation system, for adding additives to the mixed oil in the first delivery pipeline.

[0012] According to some embodiments of the first aspect of the present invention, the extreme environment simulation system includes a fuel ambient temperature path, a fuel high temperature path, and a fuel low temperature path; the fuel ambient temperature path, the fuel high temperature path, and the fuel low temperature path are arranged in parallel between the fuel supply mixing system and the fuel supply and return flow regulation system; the fuel ambient temperature path is used to simulate a ambient temperature environment, the fuel high temperature path is used to simulate a high temperature environment, and the fuel low temperature path is used to simulate a low temperature environment.

[0013] According to some embodiments of the first aspect of the present invention, the fuel room temperature path, the fuel high temperature path, and the fuel low temperature path each sequentially include a second shut-off valve, a second regulating valve, and a second flow meter in the fuel supply flow direction; the fuel high temperature path further includes a replaceable oil pipe disposed between the second regulating valve and the second flow meter on the fuel high temperature path for high temperature coking research and a heater for heating the replaceable oil pipe; the fuel low temperature path further includes a refrigerator disposed between the second regulating valve and the second flow meter on the fuel low temperature path.

[0014] According to some embodiments of the first aspect of the present invention, the extreme environment simulation system further includes a vibration simulator for applying vibration to one or more of the fuel ambient temperature path, the fuel high temperature path, and the fuel low temperature path.

[0015] According to some embodiments of the first aspect of the present invention, the extreme environment simulation system further includes a vacuum pump group, which is used to evacuate the entire extreme environment simulation system to a near-vacuum or semi-vacuum state to simulate a low-pressure environment at high altitudes and to test oil leakage in extreme environments.

[0016] According to some embodiments of the first aspect of the present invention, the fuel supply and return flow regulation system includes a fuel supply line, a main return line, and a side return line; the two ends of the fuel supply line are respectively connected to the extreme environment simulation system and the aero-engine / combustion test system, and the fuel supply line includes, in the direction of fuel supply flow, a mixer, a first regulating pump group, and a temperature / pressure sensor; the two ends of the main return line are respectively connected to the aero-engine / combustion test system and the mixing chamber, and the main return line includes, in the direction of return flow, a third shut-off valve, a third regulating valve, a third flow meter, and a fuel pump.

[0017] One end of the side return oil path is connected to the oil supply path and is located between the first regulating pump group and the temperature / pressure sensor. The other end of the side return oil path is connected to the mixing chamber. The side return oil path includes, in sequence, a fourth shut-off valve, a fourth regulating valve, a fourth flow meter and a second regulating pump group in the oil return flow direction.

[0018] According to some embodiments of the first aspect of the present invention, the first regulating pump group consists of a first large fuel pump and a first small fuel pump connected in parallel; the second regulating pump group consists of a second large fuel pump and a second small fuel pump connected in parallel.

[0019] The second aspect of the present invention also proposes an experimental method for testing a hybrid fuel supply system for extreme environment testing of sustainable aviation fuel using some embodiments of the first aspect of the present invention.

[0020] The experimental method according to a second aspect of the present invention includes the following steps:

[0021] S1: Check that the connections and functions of each device in the hybrid fuel supply system for the extreme environment test of sustainable aviation fuel are intact;

[0022] S2: Operate the fuel supply and mixing system to uniformly mix different aviation fuels according to a preset ratio to form a mixed fuel, so that the extreme simulation environment system delivers the mixed fuel at room temperature, adjust the fuel supply and return flow regulation system, and run the aero-engine / combustion test system to steady-state operating conditions;

[0023] S3: Record the fuel supply-related data under steady-state operating conditions, and simultaneously observe the operating parameters of the aero-engine / combustion test system to determine whether all indicators of the aero-engine / combustion test system and the fuel supply mixing system are normal; if normal, proceed to the next step; otherwise, troubleshoot until normal operation is achieved.

[0024] S4: Under steady-state conditions, check whether the fuel supply characteristics of the mixed oil are correct, and adjust the fuel supply and return flow regulation system to compensate for the fuel supply deviation caused by changes in fuel density and viscosity.

[0025] S5: Conduct fuel supply tests under different extreme environments and record fuel supply and combustion data under the corresponding extreme environments;

[0026] S6: Determine whether all extreme environment fuel supply tests of the preset ratio of mixed fuel have been completed. If not, allow the extreme simulation environment system to supply mixed fuel at room temperature, and simultaneously stop the operation of the fuel supply mixing system. Drain all the mixed fuel in the mixed fuel supply system for extreme environment testing of sustainable aviation fuel. Then, run the fuel supply mixing system to re-inject the preset ratio of mixed fuel into the mixed fuel supply system for extreme environment testing of sustainable aviation fuel. Repeat steps S5 and S6. If yes, proceed to step S7.

[0027] S7: Determine whether the extreme environment fuel supply test experiment of other preset ratios of mixed oil has been completed. If not, drain all the mixed oil in the mixed fuel supply system for the extreme environment test of sustainable aviation fuel, and then repeat steps S2, S3, S4, S5, S6 and S7. If yes, end the experiment.

[0028] According to the experimental method of the second aspect of the present invention, fuel supply tests of blended fuel containing sustainable aviation fuel were carried out under various extreme environments, and the test results were accurate.

[0029] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0031] Figure 1 This is a schematic diagram of the hybrid fuel supply system for extreme environment testing of sustainable aviation fuel according to a first aspect embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the oil supply and mixing system in the first aspect embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the structure of the extreme environment simulation system in the first aspect embodiment of the present invention.

[0034] Figure 4 This is a flowchart illustrating an experimental method for a hybrid fuel supply system used in extreme environment testing of sustainable aviation fuel, according to a second aspect of the present invention.

[0035] Figure label:

[0036] 1000 Hybrid Fuel Supply System for Sustainable Aviation Fuel Extreme Environment Testing

[0037] Oil supply mixing system 1

[0038] Oil supply branch 101, oil storage tank 1011, first shut-off valve 1012, first filter 1013

[0039] First regulating valve 1014, first flow meter 1015, first fuel pump 1016, mixing chamber 102

[0040] Oil drain tank 1021, mixing chamber temperature sensor 1022, mixing chamber pressure sensor 1023, pressure regulating pump 103

[0041] First delivery pipeline 104, additive branch 105, other additive containers 1051, fifth shut-off valve 1052.

[0042] Fifth regulating valve 1053; Fifth flow meter 1054; Centrifugal pump 1055

[0043] Extreme Environment Simulation System 2

[0044] Fuel ambient temperature circuit 201, fuel high temperature circuit 202, fuel low temperature circuit 203, second shut-off valve 2001

[0045] Second regulating valve 2002, second flow meter 2003, replaceable oil pipe 2021, heater 2022

[0046] Refrigeration unit 2031, vibration simulator 204, vacuum pump unit 205

[0047] Aircraft Engine / Combustion Experimental System 3

[0048] Oil supply and return flow regulation system 4

[0049] Fuel supply line 401, mixer 4011, first regulating pump set 4012, first main fuel pump 40121

[0050] First small fuel pump 40122 Temperature / pressure sensor 4013 Main return line 402

[0051] Third shut-off valve 4021; Third regulating valve 4022; Third flow meter 4023; Fuel pump 4024

[0052] Oil return filter processor 4025, side oil return line 403, fourth shut-off valve 4031, fourth regulating valve 4032

[0053] Fourth flow meter 4033; Second regulating pump set 4034; Second main fuel pump 40341

[0054] Second small fuel pump 40342 Detailed Implementation

[0055] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0056] The following is combined Figures 1 to 4 This invention describes a hybrid fuel supply system 1000 and experimental methods for extreme environment testing of sustainable aviation fuel.

[0057] like Figures 1 to 3As shown, a fuel supply system 1000 for sustainable aviation fuel extreme environment testing according to a first aspect embodiment of the present invention includes a fuel supply mixing system 1, an extreme environment simulation system 2, an aircraft engine / combustion test system 3, and a fuel supply and return flow regulation system 4; wherein, the fuel supply mixing system 1 is used to uniformly mix different aviation fuels to form a mixed fuel; the extreme environment simulation system 2 is connected to the fuel supply mixing system 1, and is used to receive and deliver the mixed fuel output by the fuel supply mixing system 1, and to simulate various extreme environments when delivering the mixed fuel; the fuel supply and return flow regulation system 4 is connected to the extreme environment simulation system 2, the aircraft engine / combustion test system 3, and the fuel supply and return flow regulation system 4, respectively. The test system 3 is connected to the fuel supply and mixing system 1. The fuel supply and return flow regulation system 4 is used to supply the mixed fuel to the aero-engine / combustion test system 3 after receiving the mixed fuel output from the extreme environment simulation system 2 and regulating the flow rate of the mixed fuel, so that the aero-engine / combustion test system 3 can operate. It also returns the mixed fuel discharged from the aero-engine / combustion test system 3 to the fuel supply and mixing system 1 in an adjustable flow rate. The fuel supply and return flow regulation system 4 is also used to return a portion of the excess mixed fuel that does not enter the aero-engine / combustion test system 3 to the fuel supply and mixing system 1 in an adjustable flow rate after receiving the mixed fuel output from the extreme environment simulation system 2 and regulating the flow rate of the mixed fuel.

[0058] Specifically, the aircraft engine / combustion test system 3 can be either an aircraft engine or a combustion test system with a combustion chamber to conduct a mixed fuel combustion process. The fuel supply and mixing system 1 is used to uniformly mix different aviation fuels to form a mixed fuel. It is understood that the fuel supply and mixing system 1 can supply different aviation fuels, such as conventional aviation kerosene and different types of sustainable aviation fuels. The fuel supply and mixing system 1 can also rapidly and uniformly mix conventional aviation kerosene and different types of sustainable aviation fuels to obtain a uniformly mixed fuel. Therefore, this invention has the function of uniformly mixing multiple different aviation fuels, resulting in a highly homogeneous mixed fuel. Supplying a highly homogeneous mixed fuel to the aircraft engine / combustion test system 3 helps ensure the stability of the combustion state of the aircraft engine / combustion test system 3, and also helps ensure the stability of the fuel supply quantity.

[0059] The extreme environment simulation system 2 is connected to the fuel supply and mixing system 1. The extreme environment simulation system 2 receives and supplies the mixed fuel output from the fuel supply and mixing system 1, and simulates various extreme environments during the supply of the mixed fuel, such as refrigeration waxing, high-temperature coking, foreign matter addition, vibration, and low-pressure leakage. Therefore, this invention can enable testing of mixed fuels containing sustainable aviation fuel under various extreme environments. It should be noted that during the experiment, multiple extreme environments can be superimposed according to experimental needs, thereby enabling experimental verification of the superposition and interaction of several extreme environments, or a single extreme environment can be simulated.

[0060] The fuel supply and return flow regulation system 4 is connected to the extreme environment simulation system 2, the aero-engine / combustion test system 3, and the fuel supply and mixing system 1, respectively. The fuel supply and return flow regulation system 4 is used to supply mixed oil to the aero-engine / combustion test system 3 after receiving the mixed oil output from the extreme environment simulation system 2 and regulating the flow rate of the mixed oil, so that the aero-engine / combustion test system 3 can operate, and to return the mixed oil discharged from the aero-engine / combustion test system 3 to the fuel supply system in an adjustable flow rate manner. The fuel supply and return flow regulation system 4 is also used to return a portion of the excess mixed oil that does not enter the aero-engine / combustion test system 3 to the fuel supply and mixing system 1 in an adjustable flow rate manner after receiving the mixed oil output from the extreme environment simulation system 2 and regulating the flow rate of the mixed oil. Understandably, the fuel supply and return flow regulation system 4 can regulate the flow rate of the mixed fuel supplied to the aero-engine / combustion test system 3, including rapidly increasing and decreasing the flow rate, as well as discharging the mixed fuel, to achieve the following functions: First, to simulate the fuel supply state when the engine is in a transitional state in reality, such as a sudden increase or decrease in fuel flow rate, so as to conduct tests on the mixed fuel and the mixed fuel supply system under such extreme conditions; Second, to compensate for the fuel supply deviation caused by changes in fuel density and viscosity, i.e., to perform fuel characteristic compensation, so as to accurately control the fuel flow rate; Third, to discharge the mixed fuel in the mixed fuel supply system 1000 for sustainable aviation fuel extreme environment testing without passing through the combustion chamber of the aero-engine or combustion test system, so as to conduct the next test experiment.

[0061] It's important to clarify that while existing fuel supply systems can accurately control the supply pressure and flow rate of traditional fuels, using a blend containing sustainable aviation fuel alters its physicochemical properties, such as viscosity, density, and lower calorific value. Furthermore, these properties change differently with temperature and pressure compared to traditional fuels. If the fuel supply system continues with its original control strategy (e.g., keeping the pump in its original state under the same operating conditions), these changes in physical properties will alter the leakage of the pump needle valve and the return flow rate of the fuel supply system, leading to deviations in the supplied fuel flow rate. Since most flow meters used for feedback control are based on volumetric flow rate measurement, their mass flow rate also needs correction after the fuel density changes. Additionally, simulating extreme environments, such as high or low temperatures, will also alter the properties of the blend. Therefore, when using a blend containing sustainable aviation fuel, it is necessary to compensate for the supply deviations caused by changes in fuel density and viscosity, based on the changes in the blend's properties, to accurately control the fuel flow rate and ensure the accuracy of experimental results.

[0062] The fuel supply system 1000 for extreme environment testing of sustainable aviation fuel according to a first aspect of the present invention has the following advantages: First, the present invention uses a fuel supply and mixing system 1 to uniformly mix different aviation fuels, thereby obtaining a fuel mixture with high mixing uniformity. Second, the present invention uses an extreme environment simulation system 2 to simulate various extreme environments, thereby enabling the present invention to conduct comprehensive experimental evaluation of fuel mixtures containing sustainable aviation fuel under extreme environments. Third, the present invention uses a fuel supply and return flow regulation system 4, which, on the one hand, can simulate a transitional environment to conduct test experiments on fuel mixtures and the fuel supply system under such extreme environments; on the other hand, it can be used for fuel characteristic compensation to ensure accurate control of fuel supply flow; furthermore, it can discharge fuel mixtures from the fuel supply system 1000 for extreme environment testing of sustainable aviation fuel without passing through the combustion chamber of the aircraft engine or combustion test system, as needed. In summary, the present invention can conduct experimental tests under various extreme environments to study and verify the characteristics and performance of fuel mixtures containing sustainable aviation fuel and the fuel supply system 1000 for extreme environment testing of sustainable aviation fuel under extreme environments.

[0063] According to some embodiments of the first aspect of the present invention, such as Figure 1 and Figure 2 As shown, the fuel supply and mixing system 1 includes multiple fuel supply branches 101, a mixing chamber 102, and a pressure regulating pump 103. Each of the multiple fuel supply branches 101 is connected to the mixing chamber 102 and is used to inject different types of aviation fuel into the mixing chamber 102. It should be noted that there are at least two fuel supply branches 101; some or all of the fuel supply branches 101 are used to inject sustainable aviation fuel into the mixing chamber 102, while the remaining fuel supply branches 101 are used to inject conventional aviation kerosene into the mixing chamber 102. The mixing chamber 102 is used to uniformly mix the injected different types of aviation fuel to form a mixed oil. Specifically, for example, a stirrer is provided at the bottom of the mixing chamber 102 to quickly and thoroughly mix the aviation fuel entering the mixing chamber 102. The mixing chamber 102 is connected to the extreme environment simulation system 2 through a first delivery pipeline 104. The pressure regulating pump 103 is installed on the first delivery pipeline 104 and is used to deliver the mixed oil from the mixing chamber 102 to the extreme environment simulation system 2 at adjustable pressure. Thus, the fuel mixing system 1 achieves uniform mixing of different aviation fuels to form a mixed oil and outputs the mixed oil at a certain pressure.

[0064] According to some embodiments of the first aspect of the present invention, such as Figure 2As shown, each fuel supply branch 101 is sequentially equipped with a fuel storage tank 1011, a first shut-off valve 1012, a first filter 1013, a first regulating valve 1014, a first flow meter 1015, and a first fuel pump 1016 in the fuel supply flow direction. It can be understood that the fuel storage tank 1011 is used to store sustainable aviation fuel or conventional aviation kerosene; the first shut-off valve 1012 is used to control the opening and closing of the fuel supply branch 101; the first filter 1013 is used to filter the aviation fuel in the fuel supply branch 101 to prevent impurities in the aviation fuel from entering the mixing chamber 102; the first regulating valve 1014 is used to regulate the flow rate of aviation fuel in the fuel supply branch 101; the first flow meter 1015 is used to monitor the flow rate of aviation fuel in the fuel supply branch 101; and the first fuel pump 1016 is used to extract aviation fuel from the fuel storage tank 1011 and, together with the first regulating valve 1014, to regulate the flow rate and pressure of aviation kerosene in the fuel supply branch 101. The opening range of the first regulating valve 1014 is 0-100%. The first regulating valve 1014 is electrically controlled and can control its own opening based on feedback.

[0065] According to some embodiments of the first aspect of the present invention, such as Figure 1 and Figure 2 As shown, the mixing chamber 102 also includes an oil drain tank 1021, which is connected to the mixing chamber 102 and is used to store the mixed oil drained from the mixing chamber 102. For example, after an extreme environment test experiment, if it is necessary to drain the mixed oil in the mixed fuel supply system 1000 for extreme environment testing of sustainable aviation fuel, the mixed oil can be discharged into the oil drain tank 1021. The mixing chamber 102 is also equipped with a mixing chamber temperature sensor 1022 and a mixing chamber pressure sensor 1023 to monitor the temperature and pressure in the mixing chamber 102, respectively.

[0066] According to some embodiments of the first aspect of the present invention, such as Figure 1 and Figure 2 As shown, the oil supply mixing system 1 also includes an additive branch 105. One end of the additive branch 105 is connected to the first delivery pipeline 104 and located between the pressure regulating pump 103 and the extreme environment simulation system 2. It is used to add additives to the mixed oil in the first delivery pipeline 104. These additives can be impurities such as sand particles, moldy substances, lubricating oil, etc. Adding additives to the mixed oil in the first delivery pipeline 104 simulates the extreme situation in actual oil supply systems where components are affected by oxidation, moisture, corrosion, sand particles, etc., potentially leading to the contamination of small foreign objects. Connecting one end of the additive branch 105 between the pressure regulating pump 103 and the extreme environment simulation system 2 prevents additives from entering the mixing chamber 102 and contaminating it.

[0067] Specifically, such as Figure 2As shown, the additive branch 105, along the direction in which the additive enters the first delivery pipeline 104, is sequentially equipped with an additional additive container 1051, a fifth shut-off valve 1052, a fifth regulating valve 1053, a fifth flow meter 1054, and a centrifugal pump 1055. The additional additive container 1051 is used to store impurities such as sand particles, moldy substances, lubricating oil, etc. The fifth shut-off valve 1052 is used to control the shut-off of the additive branch 105. The fifth flow meter 1054 is used to regulate the flow rate of the additive branch 105. The fifth regulating valve 1053 and the centrifugal pump 1055 jointly regulate the flow rate and pressure of the additive branch 105. It can be understood that sand particles can be sent into the first delivery pipeline 104 using media such as air or aviation fuel.

[0068] According to some embodiments of the first aspect of the present invention, such as Figure 1 and Figure 3 As shown, the extreme environment simulation system 2 includes a fuel ambient temperature path 201, a fuel high temperature path 202, and a fuel low temperature path 203; the fuel ambient temperature path 201, the fuel high temperature path 202, and the fuel low temperature path 203 are connected in parallel between the fuel supply and mixing system 1 and the fuel supply and return flow regulation system 4; the fuel ambient temperature path 201 is used to simulate the ambient temperature environment, the fuel high temperature path 202 is used to simulate the high temperature environment, and the fuel low temperature path 203 is used to simulate the low temperature environment. Understandably, on the one hand, by setting up a normal temperature fuel path 201, a high temperature fuel path 202, and a low temperature fuel path 203, normal temperature, high temperature, and low temperature environments can be simulated. This allows for testing of the fuel mixture and fuel supply system under corresponding extreme conditions. For example, heating the delivered fuel mixture causes it to coke, simulating the phenomenon of fuel coking in the fuel lines due to high temperatures caused by engine heat transfer in some fuel supply lines 401, thus studying the fuel supply characteristics under high temperature extreme environments. Cooling the delivered fuel mixture causes it to wax, simulating the phenomenon of wax formation in the fuel supply system under high-altitude low-temperature conditions. On the other hand, the normal temperature fuel path 201, high temperature fuel path 202, and low temperature fuel path 203 are three different fuel paths. By combining and adjusting the normal temperature fuel path 201, high temperature fuel path 202, and low temperature fuel path 203, transient adjustment (can change abruptly) of the fuel mixture temperature can be achieved, with a wide adjustment range. For example, by closing the high-temperature fuel circuit 202 and opening the low-temperature fuel circuit 203, tests related to extreme low-temperature environments can be conducted quickly without waiting for the fuel circuit to cool down. Another example is that the mixed fuel output from the normal-temperature fuel circuit 201, the high-temperature fuel circuit 202, and the low-temperature fuel circuit 203 can be mixed together to obtain a mixed fuel at a certain temperature in an instant or a very short time.

[0069] According to some embodiments of the first aspect of the present invention, such as Figure 3As shown, the normal temperature fuel path 201, high temperature fuel path 202, and low temperature fuel path 203 each include a second shut-off valve 2001, a second regulating valve 2002, and a second flow meter 2003 in the fuel supply flow direction, respectively. It can be understood that the second shut-off valve 2001 is used to control the opening and closing of the corresponding fuel path, the second regulating valve 2002 is used to regulate the flow of the corresponding fuel path, and the second flow meter 2003 is used to monitor the flow of the corresponding fuel path. The second regulating valve 2002 can cooperate with the fuel supply and return flow regulation system 4 to simulate the transitional environment and regulate the fuel supply characteristics.

[0070] like Figure 3 As shown, the high-temperature fuel circuit 202 also includes a replaceable oil pipe 2021 for high-temperature coking research, disposed between a second regulating valve 2002 and a second flow meter 2003 on the high-temperature fuel circuit 202, and a heater 2022 for heating the replaceable oil pipe 2021. The replaceable oil pipe 2021 allows for rapid replacement after coking, facilitating subsequent extreme environment experiments and enabling the study of coking performance of different oil pipes. Optionally, the replaceable oil pipe 2021 can be a straight pipe, a square-wave pipe, a spiral pipe, etc., to simulate the high-temperature coking performance of oil pipes with different shapes.

[0071] Preferably, the heater 2022 is an electromagnetic radiation heater, which uses the principle of electromagnetic induction to heat the oil pipe, resulting in fast heating speed and high heating temperature, with a maximum temperature of 500℃. The second flow meter 2003 is installed after the replaceable oil pipe 2021 that will be heated, so that the second flow meter 2003 will directly measure the flow rate of the mixed oil after the temperature change.

[0072] like Figure 3 As shown, the fuel cryogenic circuit 203 also includes a chiller 2031 disposed between the second regulating valve 2002 and the second flow meter 2003 on the fuel cryogenic circuit 203. It can be understood that the chiller 2031 is used to cool the fuel cryogenic circuit 203, with a minimum temperature reaching -60℃, for studying fuel supply characteristics under extreme low-temperature environments. The second flow meter 2003 is placed after the chiller 2031, so that the second flow meter 2003 can directly measure the mixed oil flow rate after temperature changes.

[0073] According to some embodiments of the first aspect of the present invention, such as Figure 3As shown, the extreme environment simulation system 2 also includes a vibration simulator 204. The vibration simulator 204 is used to apply vibration to one or more of the fuel ambient temperature path 201, fuel high temperature path 202, and fuel low temperature path 203, thereby causing it to vibrate with a certain amplitude, simulating the fuel supply line of the aircraft engine being subjected to different degrees of vibration, and thus allowing the study of the changes in fuel supply characteristics of the fuel ambient temperature path 201, fuel high temperature path 202, or fuel low temperature path 203 when subjected to different degrees of vibration.

[0074] According to some embodiments of the first aspect of the present invention, such as Figure 3 As shown, the extreme environment simulation system 2 also includes a vacuum pump assembly 205, which is used to evacuate the entire extreme environment simulation system 2 to a near-vacuum or semi-vacuum state to simulate the low-pressure environment at high altitudes and to perform oil leakage tests under extreme conditions. In other words, the extreme environment simulation system 2 can simulate the low-pressure environment at high altitudes, ensuring that the pipelines within the system are in a low-pressure environment, thus enabling the invention to perform oil leakage tests under low-pressure conditions. Furthermore, the invention can also perform oil leakage tests in high-temperature, low-temperature, and vibration environments.

[0075] According to some embodiments of the first aspect of the present invention, such as Figure 1 As shown, the fuel supply and return flow regulation system 4 includes a fuel supply line 401, a main return line 402, and a side return line 403. The two ends of the fuel supply line 401 are connected to the extreme environment simulation system 2 and the aero-engine / combustion test system 3, respectively. In the fuel supply flow direction, the fuel supply line 401 sequentially includes a mixer 4011, a first regulating pump group 4012, and a temperature / pressure sensor 4013. It can be understood that the mixer 4011 is used to mix the fuel mixture discharged from the normal temperature fuel line 201, the high temperature fuel line 202, and the low temperature fuel line 203 to ensure the uniformity of the fuel mixture properties. The first regulating pump group 4012 is used to regulate the pressure and flow rate of the fuel mixture entering the aero-engine / combustion test system 3. The temperature / pressure sensor 4013 is used to measure the pressure and temperature of the fuel mixture entering the aero-engine / combustion test system 3.

[0076] like Figure 1As shown, the two ends of the main return oil circuit 402 are connected to the aero-engine / combustion test system 3 and the mixing chamber 102, respectively. The main return oil circuit 402 includes, in the direction of return oil flow, a third shut-off valve 4021, a third regulating valve 4022, a third flow meter 4023, and a fuel pump 4024. The third shut-off valve 4021 is used to shut off the main return oil circuit 402; the third regulating valve 4022 is used to adjust the opening of the main return oil circuit 402 to assist in controlling the flow rate; the third flow meter 4023 is used to monitor the flow rate of the main return oil circuit 402; and the fuel pump 4024 is used to control the flow rate of the mixed oil in the main return oil circuit 402. The power and flow rate of the fuel pump 4024 are adjustable. In addition, the main return oil circuit 402 also includes a return oil filter processor 4025, which is used to filter impurities, such as metal shavings, carried by the mixed oil after passing through the aero-engine / combustion test system 3.

[0077] like Figure 1 As shown, one end of the side return oil passage 403 is connected to the oil supply passage 401 and is located between the first regulating pump group 4012 and the temperature / pressure sensor 4013. The other end of the side return oil passage 403 is connected to the mixing chamber 102. The side return oil passage 403 includes, in the direction of return oil flow, a fourth shut-off valve 4031, a fourth regulating valve 4032, a fourth flow meter 4033, and a second regulating pump group 4034. The temperature / pressure sensor 4013 is used to monitor the fuel temperature and pressure before it enters the aero-engine / combustion test system 3.

[0078] When simulating the transitional environment, i.e., the flow rate of the mixed oil entering the aero-engine / combustion test system 3 needs to increase or decrease suddenly, the first regulating pump group 4012 and the second regulating pump group 4034 can be adjusted in combination to make the flow rate change rapidly and over a wide range. By setting the first regulating pump group 4012 and the second regulating pump group 4034, the transient nature of the adjustment can be made greater, which can meet the requirements of rapidly changing the oil quantity under the transitional operating condition.

[0079] When performing fuel characteristic compensation, firstly, the mass flow rate of aviation fuel in each fuel supply branch 101 is calculated based on the reading of the first flow meter 1015 on each fuel supply branch 101 and the density of aviation fuel in the fuel storage tank 1011; that is, the mass flow rate injected into the mixing chamber 102. Secondly, after being injected into the mixing chamber 102 and stirred evenly, the viscosity, density, and lower heating value of the mixed oil in the mixing chamber 102, as well as the theoretical relationship between these properties and pressure and temperature, can be obtained through theoretical calculations based on the physicochemical properties of different aviation fuels and the blending ratios of different aviation fuels (which can be calculated based on the mass flow rate entering the mixing chamber 102 from each fuel supply branch 101). The theoretical calculation method here is a publicly available and very mature method for calculating the properties of mixed fuels. Next, the actual mass flow rate of the mixed oil is calculated based on the reading of the second flow meter 2003 in the extreme environment simulation system 2 and the density of the mixed oil. According to the theoretical fuel supply parameters (i.e. the required fuel supply quantity and fuel supply pressure) under the corresponding operating conditions of the aero-engine / combustion test system 3, the three second regulating valves 2002 in the extreme environment simulation system 2, the first regulating pump group 4012 and the second regulating pump group 4034 in the fuel supply and return flow regulation system 4, and the fuel pump 4024 on the main return oil circuit 402 are adjusted so that the measured actual mass flow rate and fuel supply pressure are equal to the theoretical fuel supply parameters, and finally the characteristic compensation under the steady state or extreme environment condition is achieved.

[0080] According to some embodiments of the first aspect of the present invention, such as Figure 1 As shown, the first regulating pump group 4012 consists of a first large fuel pump 40121 and a first small fuel pump 40122 connected in parallel; the second regulating pump group 4034 consists of a second large fuel pump 40341 ​​and a second small fuel pump 40342 connected in parallel. The first large fuel pump 40121 and the second large fuel pump 40341 ​​are mainly used to regulate the flow rate within a relatively large flow range, while the small fuel pump 4024 is mainly used to regulate the flow rate within a relatively small flow range. The combination of large and small pumps can cover a larger flow range, resulting in more precise flow rate regulation; moreover, the transient response of the regulation is greater, which can meet the needs of rapid changes in fuel quantity under transitional operating conditions.

[0081] According to some embodiments of the first aspect of the present invention, the opening range of the first regulating valve 1014, the second regulating valve 2002, the third regulating valve 4022, the fourth regulating valve 4032 and the fifth regulating valve 1053 is 0-100%, and all of them are electrically controlled and can control their own opening based on feedback.

[0082] like Figure 4 As shown, the second aspect of the present invention also proposes an experimental method for testing a hybrid fuel supply system 1000 in extreme environments using some embodiments of the first aspect of the present invention.

[0083] like Figure 4 As shown, the experimental method according to a second aspect embodiment of the present invention includes the following steps:

[0084] S1: Check the connections and functions of all equipment in the hybrid fuel supply system 1000 for extreme environment testing of sustainable aviation materials to ensure the safety and efficiency of the test process.

[0085] S2: Run the fuel supply and mixing system 1 to uniformly mix different aviation fuels according to a preset ratio to form a mixed fuel for extreme environment test experiments under the preset ratio. The extreme environment simulation system 2 delivers the mixed fuel at room temperature, adjusts the fuel supply and return flow regulation system, and runs the aero-engine / combustion test system 3 to steady-state operating conditions.

[0086] S3: Record fuel supply-related data under steady-state operating conditions, and simultaneously observe the operating parameters of the aero-engine / combustion test system 3 to determine whether all indicators of the aero-engine / combustion test system 3 and the fuel mixing system 1 are normal. If normal, proceed to the next step; otherwise, troubleshoot until normal operation is achieved. This avoids the accuracy of experimental results being affected by the instability of the aero-engine / combustion test system 3 and the fuel mixing system 1 themselves.

[0087] S4: Under steady-state conditions, it checks whether the fuel supply characteristics of the mixed oil are correct and adjusts the fuel supply and return flow regulation system 4 to compensate for the fuel supply deviation caused by changes in fuel density and viscosity, thereby ensuring the accuracy of the fuel supply.

[0088] S5: Conduct fuel supply tests under different extreme environments, such as fuel cooling fuel supply test, fuel high temperature coking fuel supply test, fuel additive fuel supply test, vibration fuel supply test, low pressure leakage test and force transition state test, and record the fuel supply and combustion data under the corresponding extreme environments to complete the extreme environment test test under the preset ratio.

[0089] S6: Determine whether all extreme environment fuel supply tests of the preset ratio of mixed oil have been completed. If not, allow the extreme environment simulation system 2 to supply mixed oil at room temperature, and simultaneously stop the operation of the fuel supply mixing system 1, drain all the mixed oil from the fuel supply system 1000 for extreme environment testing of sustainable aviation fuel, and then run the fuel supply mixing system 1 to re-inject the preset ratio of mixed oil into the fuel supply system 1000 for extreme environment testing of sustainable aviation fuel, and repeat steps S5 and S6. If yes, proceed to step S7.

[0090] S7: Determine whether the extreme environment fuel supply test experiment of other preset ratios of mixed oil has been completed. If not, drain all the mixed oil in the mixed fuel supply system 1000 for extreme environment test of sustainable aviation fuel, and then repeat steps S2, S3, S4, S5, S6 and S7. If yes, end the experiment.

[0091] According to the experimental method of the second aspect of the present invention, fuel supply tests of blended fuel containing sustainable aviation fuel were carried out under various extreme environments, and the test results were accurate.

[0092] In a specific example, an experimental method for testing a hybrid fuel supply system 1000 for extreme environment testing of sustainable aviation fuel as described in some embodiments of the first aspect of the present invention includes the following steps:

[0093] S101: Sufficient amounts of 100% pure aviation fuel, such as conventional jet fuel or sustainable aviation fuel, are stored in the storage tanks 1011 of multiple fuel supply branches 101. The pure aviation fuel must possess correct physicochemical properties such as viscosity, density, and lower calorific value. Impurities, mold, and other additives are prepared in the other additive containers 1051 of the additive branch 105. The experiment begins by connecting the aircraft engine / combustion test system 3 and checking the functionality of the mixed fuel supply system 1000 for extreme environment testing of sustainable aviation fuel, ensuring that all relevant equipment connections are complete and functioning properly.

[0094] S202: Operate the fuel supply and mixing system 1 to deliver fuel from each fuel storage tank 1011 to the mixing chamber 102 according to the preset mixing ratio. Turn on the agitator in the mixing chamber 102 to quickly and evenly mix the fuel. Turn on the fuel room temperature path 201 in the extreme environment simulation system 2. Adjust the fuel supply and return flow regulation system 4 to achieve normal steady-state fuel supply of the mixed fuel, so that the aero-engine / combustion test system 3 can operate to steady-state conditions.

[0095] S303: Record fuel supply-related data (including pressure, flow rate, etc.) under steady-state operating conditions, and simultaneously observe the operating parameters of the aero-engine / combustion test system 3 (including power (thrust), fuel consumption rate, coolant temperature, lubricating oil pressure and temperature, exhaust temperature, etc.) to determine whether the operating status of the mixed fuel supply system 1000 for the extreme environment test of sustainable aviation fuel is normal. If normal, proceed to step S404; otherwise, troubleshoot until normal operation is achieved, and then restart the experiment.

[0096] S404: Under steady-state conditions, based on the flow rate feedback from each of the second flow meters 2003 in the extreme environment simulation system 2 and the required theoretical fuel supply, the correctness of the fuel supply characteristics of the mixed oil is determined. The fuel supply and return flow regulation system 4 and the pressure regulating pump 103 are adjusted to compensate for the fuel supply deviation caused by changes in fuel density and viscosity. More specifically, the mass flow rate of aviation fuel in each fuel supply branch 101 is calculated based on the reading of the first flow meter 1015 on each fuel supply branch 101 and the density of aviation fuel in the fuel storage tank 1011, i.e., the mass flow rate injected into the mixing chamber 102. Next, after being injected into the mixing chamber 102 and stirred evenly, the viscosity, density, and lower heating value of the mixed oil in the mixing chamber 102, as well as the theoretical relationship between these properties and pressure and temperature, can be obtained through theoretical calculations based on the physicochemical properties of different aviation fuels and the blending ratio of different aviation fuels (which can be calculated based on the mass flow rate entering the mixing chamber 102 from each fuel supply branch 101). The theoretical calculation method used here is a publicly available and very mature method for calculating the properties of mixed fuels. Next, based on the reading of the second flow meter 2003 in the extreme environment simulation system 2 and the density of the mixed fuel, the actual mass flow rate of the mixed fuel is calculated. According to the theoretical fuel supply parameters (i.e., the required fuel supply quantity and pressure) under the corresponding operating conditions of the aero-engine / combustion test system 3, the three second regulating valves 2002 in the extreme environment simulation system 2, the first regulating pump group 4012 and the second regulating pump group 4034 in the fuel supply and return flow regulation system 4, and the fuel pump 4024 on the main return oil circuit 402 are adjusted to make the measured actual mass flow rate and fuel supply pressure equal to the theoretical fuel supply parameters, ultimately achieving characteristic compensation under this steady-state or extreme environmental condition.

[0097] S505: Conduct extreme environment fuel supply test experiments. For example, in a fuel cooling and waxing fuel supply test, open the low-temperature fuel circuit 203, and the refrigeration unit 2031 will start working to lower the fuel supply temperature to the required level. In a high-temperature coking fuel supply test, open the high-temperature fuel circuit 202, select the corresponding fuel line (replaceable fuel line shapes include straight lines, square wave lines, spiral lines, etc., simulating the high-temperature coking characteristics of different fuel supply system shapes), and the electromagnetic radiation heater 2022 will start working to heat the fuel to the corresponding temperature. In a temperature alternation test, transient fuel temperature regulation (which can change abruptly) is achieved by combining and adjusting the normal-temperature fuel circuit 201, the high-temperature fuel circuit 202, and the low-temperature fuel circuit 203. In an additive fuel supply test, open the fifth shut-off valve 1052 on the additive branch 105 and adjust the centrifugal pump 1... A flow rate of 0.55 allows a certain amount of impurities, moldy substances, or lubricating oil to be mixed into the extreme environment simulation system 2. For vibration fuel supply experiments, the vibration simulator 204 is activated to generate vibrations of a certain amplitude in the corresponding oil circuit, simulating the fuel supply characteristics of an aircraft engine's fuel supply pipeline under different degrees of vibration. For low-pressure leakage experiments, the vacuum pump group 205 is activated to evacuate the entire extreme environment simulation system 2 to a near-vacuum or semi-vacuum state, simulating the low-pressure environment at high altitudes and testing the leakage of the fuel supply line 401 under extreme environments such as high and low temperatures and vibration. For afterburner and other transitional state experiments, the first regulating pump group 4012, the second regulating pump group 4034, and the fuel pump 4024 are adjusted accordingly to simulate rapid changes in fuel quantity during transitional operating conditions. Some of these extreme environmental condition simulations can also be performed in combination.

[0098] S606: Record data on fuel supply and combustion under extreme environmental conditions. After recording, determine whether all extreme environmental performance tests of the fuel mixture with the specified mixing ratio have been completed. If not, run the fuel ambient temperature circuit 201, fuel high temperature circuit 202, and fuel low temperature circuit 203 in the extreme environmental simulation system 2 at ambient temperature to drain the fuel mixture from all other fuel circuits of the fuel supply system 1000 (excluding fuel supply mixing system 1) for extreme environmental testing of sustainable aviation fuel. This is to prevent high-temperature coking, low-temperature waxing, and impurities in the fuel mixture from affecting the next extreme environmental test. Refill with the fuel mixture with the preset mixing ratio. After the fuel supply mixing system 1 and the aero-engine / combustion test system 3 reach steady-state operation, repeat steps S505 and S606 until all extreme environmental performance tests of the fuel mixture with the preset mixing ratio are completed.

[0099] S707: After all extreme environmental performance tests of the fuel mixture with the preset mixing ratio are completed, determine whether extreme environmental tests of other fuel mixture ratios have been completed. If not, all fuel mixtures in the fuel supply system 1000 for extreme environmental testing of sustainable aviation fuel need to be discharged through the mixing chamber 102. Then, adjust the fuel supply ratio of multiple fuel supply branches 101 and repeat steps S202, S303, S404, S505, S606, and S707 until the extreme environmental tests of all fuel mixture ratios are completed. It should be noted that the main return fuel line can be used to discharge the fuel mixture without passing through the combustion chamber of the aircraft engine or combustion test system, thus preventing impurities in the fuel mixture from entering the combustion chamber of the aircraft engine or combustion test system.

[0100] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0101] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A hybrid fuel supply system for extreme environment testing of sustainable aviation fuel, characterized in that, This includes fuel mixing systems, extreme environment simulation systems, aero-engine / combustion experimental systems, and fuel supply and return flow regulation systems; The fuel supply and mixing system is used to uniformly mix different aviation fuels to form a mixed fuel; the extreme environment simulation system is connected to the fuel supply and mixing system, and is used to receive and deliver the mixed fuel output by the fuel supply and mixing system, and to simulate various extreme environments when delivering the mixed fuel. The extreme environment simulation system includes a fuel room temperature circuit, a fuel high temperature circuit, a fuel low temperature circuit, a vibration simulator, and a vacuum pump group. The fuel supply and return flow regulation system is connected to the extreme environment simulation system, the aero-engine / combustion test system, and the fuel supply and mixing system, respectively. The fuel supply and return flow regulation system is used to receive the mixed fuel output from the extreme environment simulation system, regulate the flow rate of the mixed fuel, supply mixed fuel to the aero-engine / combustion test system to enable its operation, and return the mixed fuel discharged from the aero-engine / combustion test system to the fuel supply and mixing system in an adjustable flow rate. The fuel supply and return flow regulation system is also used to receive the mixed fuel output from the extreme environment simulation system, regulate the flow rate of the mixed fuel, and return a portion of the excess mixed fuel that does not enter the aero-engine / combustion test system to the fuel supply and mixing system in an adjustable flow rate.

2. The hybrid fuel supply system for extreme environment testing of sustainable aviation fuel according to claim 1, characterized in that, The fuel supply and mixing system includes multiple fuel supply branches, a mixing chamber, and a pressure regulating pump. Each of the multiple fuel supply branches is connected to the mixing chamber for injecting different types of aviation fuel into the mixing chamber. The mixing chamber is used to uniformly mix the injected different types of aviation fuel to form a mixed oil. The mixing chamber is connected to the extreme environment simulation system via a first delivery pipeline. The pressure regulating pump is installed on the first delivery pipeline for adjusting the pressure of the mixed oil in the mixing chamber and delivering it to the extreme environment simulation system.

3. The hybrid fuel supply system for extreme environment testing of sustainable aviation fuel according to claim 2, characterized in that, The oil supply and mixing system also includes an additive branch, one end of which is connected to the first delivery pipeline and located between the pressure regulating pump and the extreme environment simulation system, for adding additives to the mixed oil in the first delivery pipeline.

4. The hybrid fuel supply system for extreme environment testing of sustainable aviation fuel according to claim 2, characterized in that, The fuel ambient temperature path, the fuel high temperature path, and the fuel low temperature path are connected in parallel between the fuel supply mixing system and the fuel supply and return flow regulation system; the fuel ambient temperature path is used to simulate ambient temperature environment, the fuel high temperature path is used to simulate high temperature environment, and the fuel low temperature path is used to simulate low temperature environment.

5. The hybrid fuel supply system for extreme environment testing of sustainable aviation fuel according to claim 4, characterized in that, The fuel room temperature circuit, the fuel high temperature circuit, and the fuel low temperature circuit each include a second shut-off valve, a second regulating valve, and a second flow meter in the fuel supply flow direction, respectively; the fuel high temperature circuit also includes a replaceable oil pipe for high temperature coking research and a heater for heating the replaceable oil pipe, disposed between the second regulating valve and the second flow meter on the fuel high temperature circuit; the fuel low temperature circuit also includes a refrigeration unit disposed between the second regulating valve and the second flow meter on the fuel low temperature circuit.

6. The hybrid fuel supply system for extreme environment testing of sustainable aviation fuel according to claim 5, characterized in that, The vibration simulator is used to apply vibration to one or more of the fuel ambient temperature circuit, the fuel high temperature circuit, and the fuel low temperature circuit.

7. The hybrid fuel supply system for extreme environment testing of sustainable aviation fuel according to claim 5, characterized in that, The vacuum pump assembly is used to evacuate the entire extreme environment simulation system to a near-vacuum or semi-vacuum state, to simulate the low-pressure environment at high altitudes and to test oil leakage in extreme environments.

8. The hybrid fuel supply system for extreme environment testing of sustainable aviation fuel according to any one of claims 2-7, characterized in that, The fuel supply and return flow regulation system includes a fuel supply line, a main return line, and a side return line. The two ends of the fuel supply line are respectively connected to the extreme environment simulation system and the aero-engine / combustion test system. The fuel supply line includes, in the direction of fuel supply flow, a mixer, a first regulating pump group, and a temperature / pressure sensor. The two ends of the main return line are respectively connected to the aero-engine / combustion test system and the mixing chamber. The main return line includes, in the direction of return flow, a third shut-off valve, a third regulating valve, a third flow meter, and a fuel pump. One end of the side return oil path is connected to the oil supply path and is located between the first regulating pump group and the temperature / pressure sensor. The other end of the side return oil path is connected to the mixing chamber. The side return oil path includes, in sequence, a fourth shut-off valve, a fourth regulating valve, a fourth flow meter and a second regulating pump group in the oil return flow direction.

9. The hybrid fuel supply system for extreme environment testing of sustainable aviation fuel according to claim 8, characterized in that, The first regulating pump group consists of a first large fuel pump and a first small fuel pump connected in parallel; the second regulating pump group consists of a second large fuel pump and a second small fuel pump connected in parallel.

10. An experimental method for a hybrid fuel supply system used in extreme environment testing of sustainable aviation fuel as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1: Check that the connections and functions of each device in the hybrid fuel supply system for the extreme environment test of sustainable aviation fuel are intact; S2: Operate the fuel supply and mixing system to uniformly mix different aviation fuels according to a preset ratio to form a mixed fuel, so that the extreme simulation environment system delivers the mixed fuel at room temperature, adjust the fuel supply and return flow regulation system, and run the aero-engine / combustion test system to steady-state operating conditions; S3: Record the fuel supply-related data under steady-state operating conditions, and simultaneously observe the operating parameters of the aero-engine / combustion test system to determine whether all indicators of the aero-engine / combustion test system and the fuel supply mixing system are normal; if normal, proceed to the next step; otherwise, troubleshoot until normal operation is achieved. S4: Under steady-state conditions, check whether the fuel supply characteristics of the mixed oil are correct, and adjust the fuel supply and return flow regulation system to compensate for the fuel supply deviation caused by changes in fuel density and viscosity. S5: Conduct fuel supply tests under different extreme environments and record fuel supply and combustion data under the corresponding extreme environments; S6: Determine whether all extreme environment fuel supply tests for uniformly mixing the fuel according to the preset ratio to form the mixed oil have been completed. If not, allow the extreme environment simulation system to supply the mixed oil at room temperature, and simultaneously stop the operation of the fuel supply mixing system. Drain all the mixed oil from the fuel supply system for extreme environment testing of sustainable aviation fuel. Then, run the fuel supply mixing system to re-inject the mixed oil of the preset ratio into the fuel supply system for extreme environment testing of sustainable aviation fuel. Repeat steps S5 and S6. If yes, proceed to step S7. S7: Determine whether the extreme environment fuel supply test experiment of other preset ratios of mixed oil has been completed. If not, drain all the mixed oil in the mixed fuel supply system for the extreme environment test of sustainable aviation fuel, and then repeat steps S2, S3, S4, S5, S6 and S7. If yes, end the experiment.

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