A simulation test device and test method for aircraft fuel tank pressurization system

Abstract

The present invention relates to a simulation test device for an aircraft fuel tank pressurization system, comprising an air supply system, an air extraction system, an aircraft fuel tank pressurization system, and a fuel tank; the fuel tank is provided with a ventilation inlet and a compensation gas inlet, the aircraft fuel tank pressurization system is connected to the ventilation inlet, and the air outlet of the air supply system is divided into two paths, one of which is connected to the aircraft fuel tank pressurization system to provide pressurized gas for the fuel tank, and the other is connected to the compensation gas inlet of the fuel tank after being connected in parallel with the air extraction system to provide gas compensation for the fuel tank. The gas compensation formula is obtained by improving the test method of the ground simulation of the fuel tank pressurization system of the present invention, and according to the test principle, the pressure change of the fuel tank can be simulated by the mass of gas filled or discharged, which can not only intuitively simulate the pressure change process of the fuel tank when the unmanned aerial vehicle climbs or descends, but also can use the fuel tank matching the aircraft, which greatly reduces the test cost.

Description

Technical Field

[0001] The invention relates to the field of aviation fuel system testing, and in particular to a simulation test device and a test method for an aircraft fuel tank pressurization system. Background Art

[0002] In order to prevent the boiling and excessive volatilization of fuel during high-altitude operations, the fuel tanks of small and medium-sized UAVs that use gasoline as the fuel for piston engines generally need to be equipped with a booster system. In order to ensure the flight safety of UAVs, ground simulation tests should be conducted on the fuel tank booster system according to the aircraft development procedures. According to Article 4.1.3 of my country's aviation industry standard HB7169 "Requirements for Ground Simulation Tests of Aircraft Fuel Systems", the ground simulation test bench should be equipped with a full-size test system, and Article 4.5 requires that the fuel tank booster system can simulate the three flight states of aircraft climbing, descending and level flight, so as to check and measure the changes in the pressure values ​​of each fuel tank and each accessory of the booster system within the flight envelope.

[0003] Among them, for the simulation of flight altitude and altitude change in flight state, the traditional method is to set up a vacuum generating device, so that the environmental box generates vacuum and the vacuum degree and change can be adjusted and controlled, and the environmental box is connected to the aircraft fuel tank. The vacuum degree and change of the environmental box correspond to the flight altitude and altitude change, so as to achieve the simulation of flight altitude and altitude change. Therefore, a relatively complex environmental box vacuum degree adjustment and control system and a large and noisy vacuum generating device are required. In addition, since the fuel tank is connected to the environmental box, when simulating the flight ceiling, the pressure difference between the inside and outside of the fuel tank may be close to 0.1MPa of negative pressure, and the external structure of the fuel tank must be strengthened. For this reason, the fuel tank equipped on the aircraft cannot be used directly, and a special test fuel tank needs to be made. Therefore, the traditional method is time-consuming and troublesome, the system is complex, the investment cost is high, a relatively large test site is required, and the noise is also very large.

[0004] The present invention is aimed at a certain type of mid-altitude long-flight UAV fuel tank pressurization system, and invents a simple and easy simulation test method and test device. By filling or extracting a certain amount of air flow into or out of the fuel tank, the change in relative air pressure of the fuel tank when the UAV corresponds to the climb rate or descent rate can be simulated. Moreover, the fuel tank structure does not need to be strengthened, and the type of fuel tank can be directly used for simulation tests. In the test equipment of the present invention, there is no need for an environmental chamber and a control system for controlling the vacuum degree. Only a small vacuum pump and a path of pressurized air are connected through a simple pipeline. The test device is simple and the test operation is simple. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide an aircraft fuel tank pressurization system simulation test device and test method. By filling or extracting a certain air flow rate into or out of the fuel tank, the change in the relative air pressure of the fuel tank when the UAV corresponds to the climb rate or descent rate can be simulated, thereby solving the problems in the prior art that the environmental chamber occupies a large area, the system is complex, time-consuming and labor-intensive, and the fuel tank structure needs to be strengthened.

[0006] The present invention is achieved through the following technical solutions.

[0007] A simulation test device for an aircraft fuel tank pressurization system, comprising an air supply system, an air extraction system, an aircraft fuel tank pressurization system, and a fuel tank; the fuel tank is provided with an air vent inlet and a compensating gas inlet, the aircraft fuel tank pressurization system is connected to the air vent inlet, and the air outlet of the air supply system is divided into two paths, one of which is connected to the aircraft fuel tank pressurization system to provide pressurized gas for the fuel tank, and the other is connected in parallel with the air extraction system and then connected to the compensating gas inlet of the fuel tank to provide gas compensation for the fuel tank.

[0008] Furthermore, the air outlet of the air supply system is connected to one end of a first regulating valve, the other end of the first regulating valve is connected in parallel to a first flowmeter and one end of a second regulating valve; the other end of the second regulating valve is connected in parallel to a third regulating valve and one end of a second flowmeter, the other end of the third regulating valve is connected to an air extraction system, and the other end of the second flowmeter is connected to a compensating gas inlet of the fuel tank; the first flowmeter is connected to a ventilation inlet of the fuel tank, and a first pressure sensor is provided between the first flowmeter and the ventilation inlet.

[0009] Furthermore, the other end of the second regulating valve is connected in parallel to the third regulating valve and one end of the fifth regulating valve, the other end of the fifth regulating valve is connected to one end of the second flow meter, and the fifth regulating valve is an electronic flow regulating valve.

[0010] Furthermore, the fuel tank is also provided with a liquid outlet, and the liquid outlet is provided with a third flow meter.

[0011] Furthermore, the air supply system is an air compressor unit, which includes a compressor, a filter, and an air storage tank connected in sequence, and the air outlet of the air storage tank is connected to the first regulating valve.

[0012] Furthermore, the vacuum pump system is the vacuum pump group, which includes a vacuum pump, a vacuum pressure-stabilizing tank, and a power control box. The vacuum pump is connected to the vacuum pressure-stabilizing tank, the vacuum pressure-stabilizing tank is connected to the third regulating valve, and the power control box is electrically connected to the vacuum pump for controlling the operation of the vacuum pump.

[0013] Furthermore, the aircraft fuel tank pressurization system includes an air filter, a first safety valve, a pressure reducing valve, an anti-negative pressure valve, a second safety valve, and a pressure relief valve. The air filter, the pressure reducing valve, the anti-negative pressure valve, the second safety valve, and the pressure relief valve are connected in sequence. The pressure relief valve is connected to the fuel tank. A second pressure sensor is arranged between the anti-negative pressure valve and the second safety valve. The first safety valve is arranged on the fuel tank.

[0014] A performance simulation test method for an aircraft fuel tank pressurization system. When the aircraft's flight altitude is within the range of 0 to 8000 meters, according to the formula Fill or draw a certain flow rate Q of gas into or from the fuel tank to simulate the relative pressure change of the fuel tank, so as to simulate the fuel tank pressurization system of the aircraft and verify whether the fuel tank pressurization system of the aircraft meets the design requirements and works safely and reliably. V is the volume of air in the fuel tank, is the rate of climb or the rate of descent.

[0015] Further, including level flight test, climb test, and glide test;

[0016] Level flight test: When the aircraft is on the ground or flying in the air, the corresponding aircraft fuel tank booster system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted, and the fuel tank is not filled or pumped out of gas;

[0017] Climb test: When the aircraft is climbing at a given climb rate, the corresponding aircraft fuel tank boost system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted according to the formula Calculate the gas flow rate Q2 that needs to be supplemented under the corresponding state, and fill the fuel tank with gas with a flow rate of Q2 through the gas supply system to achieve pressure compensation for the fuel tank;

[0018] Glide test: When the aircraft is in a descent at a given descent rate, the corresponding aircraft fuel tank booster system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted according to the formula The gas flow rate Q2 that needs to be extracted under the corresponding state is calculated, and gas with a flow rate of Q2 is extracted into the fuel tank through the exhaust system to achieve pressure compensation for the fuel tank.

[0019] Furthermore, the air volume V in the fuel tank is calculated based on the air volume in the fuel tank in the initial state and the fuel consumption of the fuel tank.

[0020] Further, the specific test method includes the following steps:

[0021] a) Ground preparation: The fuel tank is full of fuel, and the vehicle is started on the ground. The start time is T1, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting the compensating gas into the fuel tank are closed, and the fuel tank is not filled or extracted;

[0022] b) Continue to climb to the highest altitude: Calculate the air volume in the fuel tank as V1, continue to climb to the highest mission altitude at the maximum climb rate, the engine power is at the maximum state, adjust the corresponding aircraft fuel tank boost system bleed air pressure P1 through the air supply system, adjust the corresponding engine fuel consumption Q3, according to the air volume V1 in the fuel tank and according to the formula The gas flow rate Q2 required to be supplemented under the corresponding state is calculated, the pipeline for filling the fuel tank with compensation gas is in an open state, and the fuel tank is filled with gas with a flow rate of Q2 through the gas supply system to achieve pressure compensation for the fuel tank;

[0023] c) Maximum altitude cruise level flight: The engine power is in the cruise state, and the corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system to adjust the corresponding engine fuel consumption Q3. At the same time, the pipelines for filling and extracting the compensating gas into the fuel tank are in a closed state, and the fuel tank is not filled with or extracted with gas;

[0024] h) Continuous descent landing: Calculate the air volume in the fuel tank to be V4, and continue to glide to the ground at the maximum glide rate. The engine power is in the slow-speed state. The corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. According to the air volume V4 in the fuel tank and according to the formula The gas flow rate Q2 that needs to be extracted under the corresponding state is calculated, the pipeline for extracting compensation gas from the fuel tank is in an open state, and gas with a flow rate of Q2 is extracted into the fuel tank through the exhaust system to achieve pressure compensation for the fuel tank;

[0025] i) Ground taxiing: The engine power is in slow-speed state. The bleed air pressure P1 of the corresponding aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting compensating gas into the fuel tank are in a closed state, and gas is not filled or extracted from the fuel tank.

[0026] Furthermore, the following steps are included between step c) and step h):

[0027] d) Continue to descend to the mission altitude: Calculate the air volume in the fuel tank as V2, and continue to descend to the mission altitude at the maximum descent rate. The engine power is in the slow-speed state. The corresponding aircraft fuel tank boost system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. According to the air volume V2 in the fuel tank and according to the formula The gas flow rate Q2 that needs to be extracted under the corresponding state is calculated, the pipeline for extracting compensation gas from the fuel tank is in an open state, and gas with a flow rate of Q2 is extracted into the fuel tank through the exhaust system to achieve pressure compensation for the fuel tank;

[0028] e) Level flight at mission altitude: the engine power is in cruising state, the bleed air pressure P1 of the corresponding aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting compensating gas into the fuel tank are in a closed state, and gas is not filled into or extracted from the fuel tank;

[0029] f) Continue to climb to the highest altitude: Calculate the air volume in the fuel tank to be V3, continue to climb to the highest mission altitude at the maximum climb rate, the engine power is at the maximum state, adjust the corresponding aircraft fuel tank boost system bleed air pressure P1 through the air supply system, adjust the corresponding engine fuel consumption Q3, according to the air volume V3 in the fuel tank and according to the formula The gas flow rate Q2 required to be supplemented under the corresponding state is calculated, the pipeline for filling the fuel tank with compensation gas is in an open state, and the fuel tank is filled with gas with a flow rate of Q2 through the gas supply system to achieve pressure compensation for the fuel tank;

[0030] g) Maximum altitude cruise and level flight: The engine power is in the cruise state, and the bleed air pressure P1 of the corresponding aircraft fuel tank pressurization system is adjusted through the air supply system to adjust the corresponding engine fuel consumption Q3. At the same time, the pipelines for filling and extracting compensating gas into the fuel tank are in a closed state, and the fuel tank is not filled with or extracted with gas.

[0031] Compared with the prior art, the advantages of the present invention are: by improving the test method of simulating the fuel tank pressurization system, the present invention can simulate the pressure change of the fuel tank by the mass of gas filled or discharged according to the test principle, which can not only intuitively simulate the pressure change process of the fuel tank when the drone climbs or descends, but also can use the fuel tank of the aircraft, greatly reducing the test cost. The present invention only requires a small vacuum pump, an air compressor and some simple connections of pipelines, and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the law of change of standard atmospheric pressure with altitude;

[0033] Figure 2This is the schematic diagram of the fuel tank pressurization system of a certain type of existing UAV;

[0034] Figure 3 It is a working principle diagram of the present invention;

[0035] Figure 4 This is a typical flight mission profile;

[0036] Figure 5 It is the test flow chart;

[0037] Figure 6 Collect data for the laboratory of the present invention;

[0038] Figure 7 It is the simulation data of the test fuel tank pressure data P3 of the present invention;

[0039] Figure 8 The simulation data of the bleed air flow Q1 of the aircraft fuel tank pressurization system of the present invention;

[0040] In the figure: 1, air supply system, 2, air extraction system, 3, aircraft fuel tank pressurization system, 4, first regulating valve, 5, first flow meter, 6, second regulating valve, 7, third regulating valve, 8, second flow meter, 9, first pressure sensor, 10, third flow meter, 11, air intake arrow, 12, pressurized gas arrow, 13, negative pressure arrow, 14, fourth regulating valve, 15, fifth regulating valve, 16, fuel tank;

[0041] 101. compressor, 102. filter, 103. gas tank;

[0042] 201, vacuum pump, 202, vacuum pressure stabilizing tank, 203, power control box;

[0043] 302, air filter, 303, first safety valve, 304, pressure reducing valve, 305, negative pressure prevention valve, 306, second safety valve, 307, pressure relief valve, 308, second pressure sensor,. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0045] Brief Introduction of UAV Fuel Tank Pressurization System

[0046] like Figure 2As shown in the figure, the existing fuel tank pressurization system of a certain type of unmanned aerial vehicle consists of an air filter, a pressure reducing valve (also called a pressure regulating valve), an anti-negative pressure valve, a safety valve, a fuel tank pressure sensor, a pressure relief valve, and an air bleed pipe and a joint. The high-pressure bleed air from the engine is filtered by the air filter and adjusted to the required boost pressure of the fuel tank by the pressure reducing valve, so that the boost value of the fuel tank is maintained within the set range. An anti-negative pressure valve is set at the ventilation main port of the system. When the high-pressure bleed air pipe is blocked or the air pressure in the fuel tank decreases as the aircraft continues to slide, the fuel tank is continuously replenished with gas through the anti-negative pressure valve to prevent the fuel tank pressure from continuously decreasing, resulting in failure to supply fuel normally and the negative pressure structure of the fuel tank being compressed. A safety valve is set on the ventilation main pipe, and a safety valve is set on the fuel tank. When the pressure reducing valve fails and the engine bleed air directly enters the fuel tank inside the aircraft without pressure regulation, the pressure in the fuel tank inside the aircraft will rise. When the fuel tank pressure is higher than the opening pressure of the safety valve when the aircraft climbs, the safety valve opens to exhaust air, controls the pressure in the fuel tank within its tolerable range, and avoids the overpressure structure of the fuel tank from bursting. This existing UAV fuel tank pressurization system of a certain model is only used as an example of a specific embodiment of the present invention, and is not intended to limit the present invention, nor is it intended to limit other aircraft fuel tank pressurization systems from utilizing the aircraft fuel tank pressurization system ground simulation test and test method of the present invention.

[0047] The basis of the present invention:

[0048] In this patent, the gas above the fuel in the fuel tank (referred to as the air in the fuel tank) complies with the ideal gas state equation:

[0049] PV=nRT

[0050] In the equation: P is the pressure of the air in the tank (Pa); V is the volume of the air in the tank (m 3 );n—the amount of gas substance (mol); R—the molar gas constant; T—the temperature of the air in the fuel tank (K).

[0051] Since the heat exchange between the air in the fuel tank and the fuel and the tank wall is relatively small, and there is no direct contact with the outside air inside the fuselage, the temperature of the air in the fuel tank is not greatly affected by the outside world, so it can be assumed that T in the equation is constant; in addition, the changes in the fuel volume and the tank structure volume caused by temperature changes are negligible, so the gas volume V in the fuel tank can be considered constant. If the air volume V in the fuel tank remains unchanged, the amount of gas n will not change; R is a constant. In summary, the air in the fuel tank complies with:

[0052] P1V1=P2V2

[0053] Calculate the pressure when the fuel tank in the fuel system is filled with or exhausted with air according to 18.11.1 (2) of Aircraft Design Manual Volume 13 Powerplant System Design:

[0054]

[0055] Where:

[0056] P0—initial pressure of air in the tank (Pa); P—instantaneous pressure of air in the tank (Pa); R=287J / (Kg·K)—gas constant of air; T—air temperature (K); V—volume of air in the tank (m 3 );t—time (s); G—air mass flow rate (kg / s). Charging is positive and discharging is negative.

[0057] Slightly modifying equation 1, we get:

[0058]

[0059] In formula 2, when the air volume V in the fuel tank is constant, the air temperature T in the fuel tank is assumed to be constant, and the pressure change per unit time of the air in the fuel tank is It can be characterized by the air mass flow rate G.

[0060] Due to the gravity of the earth, the air distribution is very uneven. The closer to the ground, the greater the atmospheric pressure. However, the height H is less than 11 km. The calculation formula is shown in formula 3, and the change law is shown in Figure 1 :

[0061] P h =760(1-2.25577×10 -7 H) 5.25588 (mmHg) Formula 3

[0062] When the flight altitude is between 0-8km, the pressure changes with altitude approximately linearly. Therefore, when the aircraft is climbing or descending, the atmospheric pressure changes with altitude per unit time can be expressed as:

[0063]

[0064] because in is the climb rate (or descent rate) (m / s).

[0065] It is known that the air density ρ is 1.293 kg / m when T is 273 k (0 ° C) and the atmospheric pressure is 101300 Pa. 3 Combining equations 1, 2, and 4, we can get the air volume flow rate Q:

[0066]

[0067] According to formula 5, within the range of 0 to 8000 meters, under the given air volume (V) in the fuel tank and the aircraft's climb rate or descent rate, a certain volume flow Q is added to or drawn from the fuel tank to achieve the change in fuel tank pressure. However, when the flight altitude exceeds 8000 meters or above, Figure 1 The curve of medium pressure changing with altitude is nonlinear, so Formula 5 is not applicable to operating conditions at flight altitudes of 8,000 meters and above.

[0068] Ground simulation test of UAV fuel tank pressurization system

[0069] like Figure 3 As shown, in view of the above-mentioned existing UAV fuel tank pressurization system, the present invention designs an aircraft fuel tank pressurization system simulation test device, including an air supply system 1, an air extraction system 2, an aircraft fuel tank pressurization system 3, and a fuel tank 16; the fuel tank 16 is provided with a ventilation inlet and a compensation gas inlet, the aircraft fuel tank pressurization system 3 is connected to the ventilation inlet, and the air outlet of the air supply system 1 is divided into two paths, one of which is connected to the aircraft fuel tank pressurization system 3 to provide pressurized gas for the fuel tank 16, and the other is connected in parallel with the air extraction system 2 and then connected to the compensation gas inlet of the fuel tank 16 to provide gas compensation for the fuel tank 16.

[0070] Further, the air outlet of the air supply system 1 is connected to one end of the first regulating valve 4, the other end of the first regulating valve 4 is connected in parallel to the first flowmeter 5 and one end of the second regulating valve 6; the other end of the second regulating valve 6 is connected in parallel to the third regulating valve 7 and one end of the second flowmeter 8, the other end of the third regulating valve 7 is connected to the air extraction system 2, and the other end of the second flowmeter 8 is connected to the compensation gas inlet of the fuel tank 16; the first flowmeter 5 is connected to the ventilation inlet of the fuel tank 16, and a first pressure sensor 9 is provided between the first flowmeter 5 and the ventilation inlet. The first flowmeter 5 and the second flowmeter 8 are gas mass flowmeters (displaying SLPM).

[0071] Furthermore, the other end of the second regulating valve 6 is connected in parallel to the third regulating valve 7 and one end of the fifth regulating valve 15 , the other end of the fifth regulating valve 15 is connected to one end of the second flow meter 8 , and the fifth regulating valve 15 is an electronic flow regulating valve.

[0072] Furthermore, the fuel tank 16 is also provided with a liquid outlet, and the liquid outlet is provided with a third flow meter 10, which is a float volume flow meter.

[0073] Furthermore, the air supply system 1 is an air compressor unit, which includes a compressor 101 , a filter 102 , and an air storage tank 103 that are connected in sequence, and an air outlet of the air storage tank 103 is connected to the first regulating valve 4 .

[0074] Furthermore, the exhaust system 2 is the vacuum pump group, which includes a vacuum pump 201, a vacuum pressure-stabilizing tank 202, and a power control box 203. The vacuum pump 201 is connected to the vacuum pressure-stabilizing tank 202, the vacuum pressure-stabilizing tank 202 is connected to the third regulating valve 7, and the power control box 203 is electrically connected to the vacuum pump 201 for controlling the operation of the vacuum pump 201.

[0075] Furthermore, the aircraft fuel tank pressurization system 3 includes an air filter 302, a first safety valve 303, a pressure reducing valve 304, an anti-negative pressure valve 305, a second safety valve 306, and a pressure relief valve 307. The air filter 302, the pressure reducing valve 304, the anti-negative pressure valve 305, the second safety valve 306, and the pressure relief valve 307 are connected in sequence. The pressure relief valve 307 is connected to the fuel tank 16. A second pressure sensor 308 is arranged between the anti-negative pressure valve 305 and the second safety valve 306. The first safety valve 303 is arranged on the fuel tank 16.

[0076] This patent conducts ground simulation tests on the full flight profile including ground start, climb, level flight, and descent. The test principles are as follows:

[0077] The air compressor simulates the engine bleed air, which enters the fuel tank boost system pipeline after drying, filtering and stabilizing the pressure, and then enters the test fuel tank after being filtered by the air filter and reduced pressure by the pressure reducing valve, so that the fuel tank is pressurized. At the same time, in order to simulate the continuous consumption of fuel in the fuel tank, the fuel tank is filled with a certain volume of water, and the water is released according to the engine fuel consumption. The engine bleed air pressure P1, bleed air flow Q1, engine fuel consumption Q3, fuel tank boost value P2 and fuel tank relative air pressure compensation flow Q2 are measured by the pressure gauge (i.e. the first pressure sensor and the second pressure sensor) and the flowmeter respectively, and collected in real time by the acquisition system. Among them, the engine bleed air flow Q1 (first flowmeter) and the fuel tank relative air pressure compensation flow Q2 (second flowmeter) are measured by mass flowmeter (SLPM), and the engine fuel consumption Q3 (third flowmeter) is measured by volume flowmeter.

[0078] When the aircraft is started on the ground and flying in the air, the boost performance of the UAV fuel tank boost system is simulated on the ground. The F1 (first regulating valve) is opened to adjust the air compressor flow pressure to the bleed air pressure corresponding to the engine working state. At the same time, the F4 (fourth regulating valve) is opened to adjust the Q3 flow to the engine fuel consumption corresponding to the engine working state. At this time, since the flight altitude has not changed, the relative air pressure compensation flow Q2 of the fuel tank is zero, and F2 (second regulating valve) and F3 (third regulating valve) are in the closed state. Among them, the fourth regulating valve can be omitted, and the flow size is controlled by the third flowmeter. When the flow is 0, the fourth regulating valve is considered to be closed.

[0079] When the aircraft continues to climb, since the external atmospheric pressure decreases with the altitude, according to the above basic conclusion of the present invention, a certain flow rate Q2 of pressurized gas is directly charged into the fuel tank to compensate for the increase in relative air pressure in the fuel tank due to the increase in flight altitude and the decrease in atmospheric pressure. Figure 3 On the basis of the above-mentioned level flight test, F2 is opened to adjust the relative pressure compensation flow Q2. According to the above-mentioned basic formula 5 of the present invention, the flow Q2 is determined by the aircraft climb rate and the air volume in the fuel tank. At this time, F3 is in the closed state.

[0080] When the aircraft continues to descend, since the external atmospheric pressure increases with the altitude, according to the above-mentioned basic conclusion of the present invention, a certain flow rate Q3 of vacuum gas is directly pumped into the fuel tank to compensate for the decrease in relative air pressure in the fuel tank due to the decrease in flight altitude and the increase in atmospheric pressure. Figure 3 On the basis of the above-mentioned level flight test, F3 is opened to adjust the relative pressure compensation flow Q2. According to the above-mentioned formula 5, which is the basis of the present invention, the flow Q2 is determined by the aircraft descent rate and the air volume in the fuel tank. At this time, F2 is in the closed state.

[0081] The following introduces the performance simulation test method of aircraft fuel tank pressurization system

[0082] A performance simulation test method for an aircraft fuel tank pressurization system. When the aircraft's flight altitude is within the range of 0 to 8000 meters, according to the formula Fill or draw a certain flow rate Q of gas into or from the fuel tank to simulate the relative pressure change of the fuel tank, so as to simulate the fuel tank pressurization system of the aircraft and verify whether the fuel tank pressurization system of the aircraft meets the design requirements and works safely and reliably. V is the volume of air in the fuel tank, is the rate of climb or the rate of descent.

[0083] Further, including level flight test, climb test, and glide test;

[0084] Level flight test: When the aircraft is on the ground or flying in the air, the corresponding aircraft fuel tank booster system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted, and the fuel tank is not filled or pumped out of gas;

[0085] Climb test: When the aircraft is climbing at a given climb rate, the corresponding aircraft fuel tank boost system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted according to the formula Calculate the gas flow rate Q2 that needs to be supplemented under the corresponding state, and fill the fuel tank with gas with a flow rate of Q2 through the gas supply system to achieve pressure compensation for the fuel tank;

[0086] Glide test: When the aircraft is in a descent at a given descent rate, the corresponding aircraft fuel tank booster system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted according to the formula The gas flow rate Q2 that needs to be extracted under the corresponding state is calculated, and gas with a flow rate of Q2 is extracted into the fuel tank through the exhaust system to achieve pressure compensation for the fuel tank.

[0087] Furthermore, the air volume V in the fuel tank is calculated based on the air volume in the fuel tank in the initial state and the fuel consumption of the fuel tank.

[0088] The following is the specific operation method of the ground simulation test

[0089] According to the system principle Figure 3 Make the connections and perform system pressure maintenance operations before the test to ensure that the entire test device and the pressurization system are sealed and leak-proof during operation.

[0090] Below is a typical mission profile of a certain type of aircraft ( Figure 4 ) The ground simulation test method of the UAV fuel tank pressurization system is described. The test flow chart is shown in Figure 5 .

[0091] The specific test method includes the following steps:

[0092] a. Ground preparation: The fuel tank is full of fuel, and the vehicle is started on the ground. The start time is T1, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting the compensating gas into the fuel tank are closed, and the fuel tank is not filled or extracted;

[0093] b. Continue to climb to the highest altitude: Calculate the air volume in the fuel tank to be V1, and continue to climb to the highest mission altitude at the maximum climb rate. The engine power is at the maximum state. The corresponding aircraft fuel tank boost system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. According to the air volume V1 in the fuel tank and according to the formula The gas flow rate Q2 required to be supplemented under the corresponding state is calculated, the pipeline for filling the fuel tank with compensation gas is in an open state, and the fuel tank is filled with gas with a flow rate of Q2 through the gas supply system to achieve pressure compensation for the fuel tank;

[0094] c. Maximum altitude cruise level flight: The engine power is in the cruise state, and the corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting the compensating gas into the fuel tank are in a closed state, and the fuel tank is not filled or extracted with gas;

[0095] d. Continue to descend to the mission altitude: Calculate the air volume in the fuel tank to be V2, and continue to descend to the mission altitude at the maximum descent rate. The engine power is in the slow-speed state. The corresponding aircraft fuel tank boost system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. According to the air volume V2 in the fuel tank and according to the formula The gas flow rate Q2 that needs to be extracted under the corresponding state is calculated, the pipeline for extracting compensation gas from the fuel tank is in an open state, and gas with a flow rate of Q2 is extracted into the fuel tank through the exhaust system to achieve pressure compensation for the fuel tank;

[0096] e. Level flight at mission altitude: The engine power is in cruising state. The corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting the compensating gas into the fuel tank are in a closed state, and the fuel tank is not filled or extracted with gas;

[0097] f. Continue to climb to the highest altitude: Calculate the air volume in the fuel tank to be V3, and continue to climb to the highest mission altitude at the maximum climb rate. The engine power is at the maximum state. The corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. According to the air volume V3 in the fuel tank and according to the formula The gas flow rate Q2 required to be supplemented under the corresponding state is calculated, the pipeline for filling the fuel tank with compensation gas is in an open state, and the fuel tank is filled with gas with a flow rate of Q2 through the gas supply system to achieve pressure compensation for the fuel tank;

[0098] g. Maximum altitude cruise level flight: The engine power is in the cruise state, and the corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system to adjust the corresponding engine fuel consumption Q3. At the same time, the pipelines for filling and extracting the compensating gas into the fuel tank are in a closed state, and the fuel tank is not filled with or extracted with gas;

[0099] h. Continuous descent landing: Calculate the air volume in the fuel tank to be V4, and continue to glide to the ground at the maximum descent rate. The engine power is in the slow-speed state. The corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. According to the air volume V4 in the fuel tank and according to the formula The gas flow rate Q2 that needs to be extracted under the corresponding state is calculated, the pipeline for extracting compensation gas from the fuel tank is in an open state, and gas with a flow rate of Q2 is extracted into the fuel tank through the exhaust system to achieve pressure compensation for the fuel tank;

[0100] i. Ground taxiing: The engine power is in the slow-speed state. The bleed air pressure P1 of the corresponding aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting compensating gas into the fuel tank are in the closed state, and the fuel tank is not filled with or extracted with gas.

[0101] Among them, the calculation in step b, step d, step f, and step h to obtain the air volume in the fuel tank is performed by calculating the fuel consumption to obtain the air volume V in the fuel tank under each operating condition. The fuel consumption of each operating condition is different. The fuel consumption of the operating condition is determined based on the fuel consumption per minute and the set flight time, and the air volume V in the fuel tank is calculated accordingly.

[0102] Test results: Figure 6 and Figure 7 As shown, after comparing the actual test data with the test fuel tank simulation data, it is found that the pressure change trends of the fuel tank are consistent, indicating that the test device and test method of the present invention can be used for the simulation test of the aircraft fuel tank pressurization system, and the test results are accurate.

[0103] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A simulation test method for an aircraft fuel tank pressurization system, characterized in that: The invention comprises an air supply system (1), an air extraction system (2), an aircraft fuel tank pressurization system (3), and a fuel tank (16); the fuel tank (16) is provided with an air inlet and a compensation gas inlet, the aircraft fuel tank pressurization system (3) is connected to the air inlet, the air outlet of the air supply system (1) is divided into two paths, one of which is connected to the aircraft fuel tank pressurization system (3) to provide pressurized gas for the fuel tank (16), and the other is connected in parallel with the air extraction system (2) and then connected to the compensation gas inlet of the fuel tank (16) to provide gas compensation for the fuel tank (16), the air outlet of the air supply system (1) is connected to one end of a first regulating valve (4), and the The other end of the first regulating valve (4) is connected in parallel to the first flow meter (5) and one end of the second regulating valve (6); the other end of the second regulating valve (6) is connected in parallel to the third regulating valve (7) and one end of the second flow meter (8); the other end of the third regulating valve (7) is connected to the air extraction system (2), and the other end of the second flow meter (8) is connected to the compensation gas inlet of the fuel tank (16); the first flow meter (5) is connected to the ventilation inlet of the fuel tank (16), and a first pressure sensor (9) is provided between the first flow meter (5) and the ventilation inlet. When the flight altitude of the aircraft is within the range of 0 to 8000 meters, according to the formula Fill or draw a certain flow rate Q of gas into or from the fuel tank to simulate the relative pressure change of the fuel tank, so as to simulate the fuel tank pressurization system of the aircraft and verify whether the fuel tank pressurization system of the aircraft meets the design requirements and works safely and reliably. V is the volume of air in the fuel tank, is the rate of climb or the rate of descent.

2. The aircraft fuel tank pressurization system simulation test method according to claim 1, characterized in that: Including level flight test, climb test, and glide test; Level flight test: When the aircraft is on the ground or flying in the air, the corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted, without the need to perform pressure compensation for filling or extracting gas from the fuel tank; Climb test: When the aircraft is climbing at a given climb rate, the corresponding aircraft fuel tank boost system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted according to the formula Calculate the gas flow rate Q2 that needs to be supplemented under the corresponding state, and fill the fuel tank with gas with a flow rate of Q2 through the gas supply system to achieve pressure compensation for the fuel tank; Glide test: When the aircraft is in a descent at a given descent rate, the corresponding aircraft fuel tank booster system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted according to the formula The gas flow rate Q2 that needs to be extracted under the corresponding state is calculated, and gas with a flow rate of Q2 is extracted into the fuel tank through the exhaust system to achieve pressure compensation for the fuel tank.

3. The aircraft fuel tank pressurization system simulation test method according to claim 1 or 2, characterized in that: The air volume V in the fuel tank is calculated based on the air volume in the fuel tank in the initial state and the fuel consumption in the fuel tank.

4. The aircraft fuel tank pressurization system simulation test method according to claim 1 or 2, characterized in that: The specific test method includes the following steps: a) Ground preparation: The fuel tank is full of fuel, and the vehicle is started on the ground. The start time is T1, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting the compensating gas into the fuel tank are closed, and the fuel tank is not filled or extracted; b) Continue to climb to the highest altitude: Calculate the air volume in the fuel tank as V1, continue to climb to the highest mission altitude at the maximum climb rate, the engine power is at the maximum state, adjust the corresponding aircraft fuel tank boost system bleed air pressure P1 through the air supply system, adjust the corresponding engine fuel consumption Q3, according to the air volume V1 in the fuel tank and according to the formula The gas flow rate Q2 required to be supplemented under the corresponding state is calculated, the pipeline for filling the fuel tank with compensation gas is in an open state, and the fuel tank is filled with gas with a flow rate of Q2 through the gas supply system to achieve pressure compensation for the fuel tank; c) Maximum altitude cruise level flight: The engine power is in the cruise state, and the corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system to adjust the corresponding engine fuel consumption Q3. At the same time, the pipelines for filling and extracting the compensating gas into the fuel tank are in a closed state, and the fuel tank is not filled with or extracted with gas; h) Continuous descent landing: Calculate the air volume in the fuel tank to be V4, and continue to glide to the ground at the maximum glide rate. The engine power is in the slow-speed state. The corresponding bleed air pressure P1 of the aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. According to the air volume V4 in the fuel tank and according to the formula The gas flow rate Q2 that needs to be extracted under the corresponding state is calculated, the pipeline for extracting compensation gas from the fuel tank is in an open state, and gas with a flow rate of Q2 is extracted into the fuel tank through the exhaust system to achieve pressure compensation for the fuel tank; i) Ground taxiing: The engine power is in slow-speed state. The bleed air pressure P1 of the corresponding aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting compensating gas into the fuel tank are in a closed state, and gas is not filled or extracted from the fuel tank.

5. The aircraft fuel tank pressurization system simulation test method according to claim 4, characterized in that: The following steps are also included between step c) and step h): d) Continue to descend to the mission altitude: Calculate the air volume in the fuel tank as V2, and continue to descend to the mission altitude at the maximum descent rate. The engine power is in the slow-speed state. The corresponding aircraft fuel tank boost system bleed air pressure P1 is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. According to the air volume V2 in the fuel tank and according to the formula The gas flow rate Q2 that needs to be extracted under the corresponding state is calculated, the pipeline for extracting compensation gas from the fuel tank is in an open state, and gas with a flow rate of Q2 is extracted into the fuel tank through the exhaust system to achieve pressure compensation for the fuel tank; e) Level flight at mission altitude: the engine power is in cruising state, the bleed air pressure P1 of the corresponding aircraft fuel tank pressurization system is adjusted through the air supply system, and the corresponding engine fuel consumption Q3 is adjusted. At the same time, the pipelines for filling and extracting compensating gas into the fuel tank are in a closed state, and gas is not filled into or extracted from the fuel tank; f) Continue to climb to the highest altitude: Calculate the air volume in the fuel tank to be V3, continue to climb to the highest mission altitude at the maximum climb rate, the engine power is at the maximum state, adjust the corresponding aircraft fuel tank boost system bleed air pressure P1 through the air supply system, adjust the corresponding engine fuel consumption Q3, according to the air volume V3 in the fuel tank and according to the formula The gas flow rate Q2 required to be supplemented under the corresponding state is calculated, the pipeline for filling the fuel tank with compensation gas is in an open state, and the fuel tank is filled with gas with a flow rate of Q2 through the gas supply system to achieve pressure compensation for the fuel tank; g) Maximum altitude cruise and level flight: The engine power is in the cruise state, and the bleed air pressure P1 of the corresponding aircraft fuel tank pressurization system is adjusted through the air supply system to adjust the corresponding engine fuel consumption Q3. At the same time, the pipelines for filling and extracting compensating gas into the fuel tank are in a closed state, and the fuel tank is not filled with or extracted with gas.

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