Fuel oil icing test system and test method based on online water injection

Abstract

The invention relates to a fuel oil icing test system and test method based on online water injection. The system comprises an oil supply device used for supplying fuel oil; the on-line water injection device is connected with the oil supply device and is used for providing a preset amount of water or emulsion in real time according to the supply amount of the fuel oil so as to be mixed with the fuel oil to form oil-water mixed liquid; the refrigerating device is connected with the oil supply device and is used for cooling the fuel oil provided by the oil supply device to a preset temperature; and the environment temperature box is internally provided with an engine fuel accessory, the environment temperature box provides environment conditions of a preset temperature for the engine fuel accessory, and an inlet of the engine fuel accessory can receive the oil-water mixed liquid. According to the invention, the uniformity of water-oil mixing can be ensured, water can be prevented from being frozen and attached to a fuel pipeline or other accessories at a low temperature, the phenomena of water accumulation and ice accumulation in low-lying and low-flow-rate areas of a system can be avoided, and the confidence coefficient of a fuel icing test is improved.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engine fuel system testing, and in particular to a fuel icing testing system and a testing method based on online water injection. Background Art

[0002] When an aircraft is flying at high altitude, the ambient temperature will decrease due to the increase in altitude. The water mixed in the aircraft fuel will form ice, which may clog the engine fuel filter, fuel accessories, etc., thereby reducing or interrupting the fuel flow to the engine, causing the engine to work abnormally or even stall.

[0003] A fuel freezing tester is usually used to simulate fuel freezing conditions and verify the impact of a certain concentration of oil-water mixture on the engine fuel system.

[0004] The current fuel icing tester mainly adopts the form of offline water injection: that is, before the formal test, a specified amount of pure water is injected at room temperature at one time, then circulated and mixed evenly, and cooled to a specified temperature; during the formal test, the evenly mixed oil-water mixture is provided to the engine fuel system inlet at a certain flow rate. The fuel icing test based on offline water injection mainly has the following problems: 1) The uniformity of oil-water mixing is poor, and it is difficult to ensure that the oil and water in the system are fully mixed by circulating mixing; 2) At low temperatures, water will freeze and adhere to the fuel lines or other accessories; 3) Water and ice will accumulate in the low-lying and low-flow areas of the system.

[0005] In order to solve the above problems and improve the confidence of the fuel freezing test, it is urgent to provide a fuel freezing test system and test method based on online water injection. Summary of the invention

[0006] To this end, the present invention provides a fuel freezing test system and test method based on online water injection, which can ensure the uniformity of water-oil mixing, prevent water from freezing and adhering to fuel pipes or other accessories at low temperatures, avoid water and ice accumulation in low-lying and low-flow rate areas of the system, and improve the confidence of the fuel freezing test.

[0007] In order to solve the above technical problems, the present invention provides a fuel freezing test system based on online water injection, comprising: A fuel supply device, used for supplying fuel; An online water injection device, connected to the oil supply device, for providing a predetermined amount of water or emulsion in real time according to the supply amount of the fuel, so as to mix with the fuel to form an oil-water mixture; a refrigeration device, connected to the fuel supply device, and used to cool the fuel provided by the fuel supply device to a predetermined temperature; An environmental temperature box is provided with an engine fuel accessory, wherein the environmental temperature box provides an environmental condition of a predetermined temperature for the engine fuel accessory, and an inlet of the engine fuel accessory is capable of receiving the oil-water mixture.

[0008] In one embodiment of the present invention, the oil supply device comprises a circulating refrigeration circuit, the circulating refrigeration circuit comprises an oil supply tank, an oil supply valve, an oil supply pump, a heat exchanger, a flow meter and a circulating pump connected in sequence; the oil supply tank is connected to a first drain valve; The heat exchanger is connected to the refrigeration device; The fuel supply pump can pump out the fuel in the fuel supply tank, absorb the cooling capacity of the refrigeration device through the heat exchanger, and the refrigerated fuel is returned to the fuel supply tank through the circulation pump.

[0009] In one embodiment of the present invention, a pressure regulating circuit is further included, which includes a regulating valve connected to the oil side outlet of the heat exchanger, and the regulating valve is connected to the inlet end of the fuel supply pump; the regulating valve can control the flow of bypass return oil to the inlet of the fuel supply pump to adjust the fuel supply pressure.

[0010] In one embodiment of the present invention, the oil supply device further comprises an oil-water mixed supply circuit, and the oil-water mixed supply circuit comprises a static mixer, a circulation pump and a first three-way valve; The first end of the flow meter is connected to the oil side outlet of the heat exchanger, and the online water injection device is connected to a water injection nozzle; the second end of the flow meter, the water injection nozzle, the static mixer and the first end of the first three-way valve are connected in sequence; the second end of the first three-way valve is connected to the inlet of the engine fuel accessory; the second end of the flow meter, the circulation pump and the inlet of the engine fuel accessory are connected in sequence; The online water injection device can configure corresponding water or emulsion in real time according to the flow rate collected by the flow meter, and inject it into the fuel pipeline through the water injection nozzle, mix it with the fuel in the static mixer, and the mixed oil-water mixture is circulated through the circulation pump for secondary mixing and then supplied to the engine fuel accessory. The circulation pump is used to crush the water droplets that are not fully mixed to promote the secondary mixing with the oil so as to mix it evenly.

[0011] In one embodiment of the present invention, the online water injection device is configured to inject a predetermined amount of fuel and a predetermined amount of water into an emulsion proportioning tank in advance, and mix the oil and water evenly by vibration, stirring, etc. When it is used, the amount of the mixed liquid is controlled by a metering pump and injected into the fuel pipeline through the water injection nozzle; Alternatively, the online water injection device is configured as a mixer, and the fuel enters the mixer at a predetermined flow rate; water is injected into the mixer at a set ratio through an atomizing nozzle, and instantly mixed with the fuel to form an emulsion, and the mixed emulsion is injected into the fuel pipeline through the water injection nozzle.

[0012] In one embodiment of the present invention, a sampling port is provided between the static mixer and the first three-way valve.

[0013] In one embodiment of the present invention, it further comprises a second three-way valve, a third three-way valve, a fourth three-way valve, a circulating water removal circuit and a circulating filtration circuit, wherein the circulating water removal circuit comprises an oil-water separator, and the circulating filtration circuit comprises a first filter; The first end and the second end of the second three-way valve are connected to the inlet end and the outlet end of the oil-water separator respectively, and the third end of the second three-way valve is connected to the third end of the first three-way valve; The first end, the second end and the third end of the third three-way valve are connected to the outlet end of the oil-water separator, the inlet end and the outlet end of the first filter respectively; The first end and the second end of the fourth three-way valve are respectively connected to the outlet end of the first filter and the oil return end of the oil supply tank.

[0014] In one embodiment of the present invention, it further comprises an oil post-processing circuit, wherein the oil post-processing circuit comprises a second filter, a fifth three-way valve, an oil return tank, an oil return valve and an oil return pump; The outlet of the engine fuel accessory is connected to the first end of the fifth three-way valve through the second filter, and the second end and the third end of the fifth three-way valve are connected to the return oil tank and the supply oil tank respectively; The oil return tank, the oil return valve and the oil return pump are connected in sequence, the third end of the fourth three-way valve is connected to the oil return tank, and the oil return pump is respectively connected to the third end of the second three-way valve and the third end of the first three-way valve; the oil return tank is connected to a second drain valve.

[0015] In one embodiment of the present invention, the water injection nozzle is an atomizing nozzle, and the sprayed liquid has a good atomization effect.

[0016] The present invention also provides a fuel freezing test method based on online water injection, using the fuel freezing test system based on online water injection, comprising: Oil and water preparation stage: S1: injecting fuel into the fuel supply tank, controlling and starting the fuel supply pump, switching the fuel supply device to the circulating filter loop to filter the fuel, and testing the fuel particle size; S2: After the fuel particle size test is qualified, the refrigeration device is controlled to start, the fuel temperature at the oil side outlet of the heat exchanger is controlled to be 29°C±3°C, and the water injection device is controlled to inject a predetermined amount of water or emulsion into the system through the water injection nozzle to make the water content of the fuel in the system supersaturated; S3: Control the oil supply device to switch to the circulating water removal circuit to perform circulating water removal; sample every 1 hour, if the water content is 80ppm-90ppm, and the saturated water content of the fuel at 30°C is 68±5ppm, the predetermined target is met; S4: After the moisture content meets the predetermined target, the oil supply device is controlled to switch to the circulating refrigeration circuit to perform circulating refrigeration, and at the same time, the environmental temperature box performs synchronous refrigeration, so that the working temperature of the fuel in the system and the inlet temperature of the engine fuel accessories simultaneously reach the corresponding predetermined low temperature conditions; Water injection test phase: S5: Control the fuel supply device to switch to the fuel supply pressure regulating circuit, so that the fuel is supplied to the engine fuel accessory, and the fuel is returned from the engine fuel accessory to the oil return tank, and the opening of the throttle valve is adjusted through closed-loop control to adjust the inlet pressure of the engine fuel accessory; S6: adjusting and controlling the engine fuel accessory to a desired speed through a transmission device according to actual working conditions; S7: Control the oil supply device to switch to the oil-water mixed supply circuit, and adopt a fixed ratio control method to control the flow rate of water or emulsion injected by the online water injection device to follow the change of the fuel supply amount in real time, so that the water or emulsion flow rate is proportional to the fuel supply flow rate, ensuring that the water content of the fuel at the inlet of the engine fuel accessory is within the range of 290-330ppm; S8: During the test, the fuel inlet of the engine fuel accessories is collected regularly for water detection to confirm that the water content of the fuel is within the range of 290-330ppm; Post-test processing stage: S9: After the test, the online water injection device, the transmission device, the environmental temperature box, the refrigeration device and the oil supply device are closed in sequence, and the oil return tank is left to stand for several hours, and then the second drain valve is opened to drain the water deposited at the bottom of the oil return tank; S10: Control to open the oil supply device, switch to the oil post-processing circuit, and separate the free water in the oil return tank through the oil-water separator; S11: Sampling inspection: if the water content of the separated fuel meets the saturated water content condition at the temperature, the water removal is stopped and the fuel is returned to the fuel supply tank.

[0017] The above technical solution of the present invention has the following advantages compared with the prior art: The fuel freezing test system and test method based on online water injection described in the present invention can prepare a certain flow of oil-water mixture in real time under low temperature conditions by injecting a specified flow of water or emulsion through an online water injection device and supply it to the engine fuel accessory inlet. The flow of the emulsion and the fuel can be accurately controlled in real time to ensure the accuracy and controllability of the supplied oil-water mixture, thereby improving the confidence of the fuel freezing test.

[0018] The invention is based on an online water injection method to configure an oil-water mixture in real time. After the oil-water mixture is evenly mixed through an oil-water mixing supply circuit, it is immediately supplied to the engine fuel accessories. This avoids the problem that during offline water injection, the oil-water mixture is circulated through an oil supply device to prepare the mixture, and water is deposited in low-lying, low-flow rate areas of the pipeline system, causing the concentration of the mixture actually supplied to the engine fuel accessories to not meet the requirements.

[0019] The present invention ensures the primary mixing of the oil-water mixture through a static mixer, and the mixed oil-water mixture is circulated by a circulating pump for secondary mixing and then supplied to the engine fuel accessories. The circulating pump can crush water droplets that are not fully mixed to promote secondary mixing with the oil, thereby ensuring uniform mixing of the oil-water mixture. The circulation of the circulating pump can ensure that the flow rate of the mixed liquid supplied to the inlet of the engine fuel accessories under different working conditions is not less than 0.7m / s, thereby preventing water from freezing and adhering to the fuel pipeline or other accessories at low temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0021] Figure 1 It is a structural principle diagram of the fuel freezing test system based on online water injection of the present invention.

[0022] Figure 2 It is a structural principle diagram of the oil supply device of the present invention.

[0023] Description of the Figures in the Specification: 1. Oil supply tank; 2. Oil supply pump; 3. Heat exchanger; 4. Refrigeration device; 6. Oil-water separator; 7. First filter; 8. Flow meter; 9. Water injection nozzle; 10. Static mixer; 11. Online water injection device; 12. Circulation pump; 13. Sampling port; 14. Engine fuel accessories; 15. Second filter; 16. Oil return pump; 17. First drain valve; 18. Second drain valve; 19. Oil return tank; F1, oil supply valve; F2, regulating valve; F3, first three-way valve; F4, second three-way valve; F5, third three-way valve; F6, fourth three-way valve; F7, oil return valve; F8, fifth three-way valve. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0025] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0026] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0027] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0028] Example 1 Reference Figure 1 As shown, a fuel icing test system based on online water injection in this embodiment includes: A fuel supply device, used for supplying fuel; An online water injection device 11, connected to the oil supply device, is used to provide a predetermined amount of water or emulsion (oil-water mixture) in real time according to the supply amount of the fuel, so as to mix with the fuel to form an oil-water mixture; A refrigeration device 4, connected to the fuel supply device, for cooling the fuel supplied by the fuel supply device to a predetermined temperature; and maintaining a constant fuel supply temperature during the test phase; The environmental temperature box has an engine fuel accessory 14 built in it. The environmental temperature box provides an environmental condition of a predetermined temperature for the engine fuel accessory 14. The inlet of the engine fuel accessory 14 can receive the oil-water mixture.

[0029] Through the above arrangement, the oil supply device, the online water injection device 11 and the refrigeration device 4 can provide an oil-water mixture of specified pressure, specified low temperature and specified concentration to the inlet of the engine fuel accessory 14. The environmental temperature box provides environmental conditions of specified temperature for the engine fuel accessory 14. The refrigeration device 4 cools the fuel in the oil supply device to a specified low temperature during the test preparation stage, and maintains the oil supply temperature constant during the test stage, thereby ensuring the uniformity of the water-oil mixture, preventing water from freezing and adhering to the fuel pipeline or other accessories at low temperatures, avoiding water and ice accumulation in the low-lying and low-flow area of ​​the system, and improving the confidence of the fuel freezing test.

[0030] It should be noted that it also includes a transmission device and a supporting system. The transmission device provides the required speed and power for the engine fuel accessory 14; the supporting system provides the required water, electricity and gas for each device, and collects and controls related test signals.

[0031] Reference Figure 2 As shown, the oil supply device includes a circulating refrigeration circuit, and the circulating refrigeration circuit includes an oil supply tank 1, an oil supply valve F1, an oil supply pump 2, a heat exchanger 3, a flow meter 8 and a circulating pump 12 connected in sequence; the oil supply tank 1 is connected to a first drain valve 17; The heat exchanger 3 is connected to the refrigeration device 4; The fuel supply pump 2 can pump out the fuel in the fuel supply tank 1, absorb the cooling capacity of the refrigeration device 4 through the heat exchanger 3, and the refrigerated fuel is returned to the fuel supply tank 1 through the circulation pump 12, realizing the fuel refrigeration function through circulation.

[0032] Specifically, it also includes a pressure regulating circuit, which includes a regulating valve F2 connected to the oil side outlet of the heat exchanger 3, and the regulating valve F2 is connected to the inlet end of the fuel supply pump 2; the regulating valve F2 can control the flow of bypass return oil to the inlet of the fuel supply pump 2 to adjust the fuel supply pressure and ensure that the pressure supplied to the inlet of the engine fuel accessory 14 is within the required range.

[0033] Specifically, the oil supply device further includes an oil-water mixed supply circuit, and the oil-water mixed supply circuit includes a static mixer 10, a circulation pump 12 and a first three-way valve F3; The first end of the flow meter 8 is connected to the oil side outlet of the heat exchanger 3, and the online water injection device 11 is connected to the water injection nozzle 9; the second end of the flow meter 8, the water injection nozzle 9, the static mixer 10 and the first end of the first three-way valve F3 are connected in sequence; the second end of the first three-way valve F3 is connected to the inlet of the engine fuel accessory 14; the second end of the flow meter 8, the circulation pump 12 and the inlet of the engine fuel accessory 14 are connected in sequence; in addition, a pressure gauge and a temperature gauge are also provided in front of the inlet of the engine fuel accessory 14.

[0034] The online water injection device 11 can configure the corresponding water or emulsion in real time according to the flow rate collected by the flow meter 8, and inject it into the fuel pipeline through the water injection nozzle 9, and mix it with the fuel in the static mixer 10. The mixed oil-water mixture is circulated through the circulation pump 12 for secondary mixing and then supplied to the engine fuel accessory 14. The circulation pump 12 is used to crush the water droplets that are not fully mixed to promote the secondary mixing with the oil. After a period of circulation, it is ensured that the mixed liquid supplied to the engine fuel accessory 14 is uniform.

[0035] It is understood that the refrigeration device 4 can generate a low-temperature refrigerant (such as Freon or other refrigerants), remove heat through a refrigeration cycle (usually based on compression, condensation, expansion and evaporation processes), and cool the refrigerant to a desired temperature. The heat exchanger 3 serves as a heat transfer medium, and uses the refrigerant generated by the refrigeration device 4 to absorb heat from the fuel or other medium, thereby achieving fuel cooling.

[0036] Furthermore, considering that under low temperature conditions, the oil-water mixture will freeze and adhere to the inner wall of the fuel pipeline at a low flow rate, the flow rate through the pipeline should not be less than 0.7m / s; and the flow rate required by the engine fuel accessory 14 under different operating conditions varies greatly. In order to ensure that the flow rate through the pipeline is not less than 0.7m / s under all operating conditions, a circulating pump 12 is designed to circulate the oil supplied to the inlet of the engine fuel accessory 14.

[0037] In addition, in order to avoid the existence of water accumulation and depression structures in each pipeline, special sealing is considered for each pipeline disassembly interface to prevent water deposition. The seal is made of a seal (ring) processed from a polytetrafluoroethylene plate and two concave flanges for sealing. The overlap between the outer diameter of the seal and the outer diameter of the concave flange is within a tolerance of 0.05mm, and the inner diameter of the seal is equal to the inner diameter of the concave flange. The weld on the inner wall of the pipeline should slightly protrude from the pipeline wall, and the weld surface is not allowed to have defects such as cracks, pits, pores, and slag inclusions.

[0038] Specifically, the online water injection device 11 is configured to inject a predetermined amount of fuel and a predetermined amount of water into the emulsion proportioning tank in advance, and mix the oil and water evenly by vibration, stirring, etc. When it is used, the amount of the mixed liquid is controlled by a metering pump and injected into the fuel pipeline through the water injection nozzle 9; Alternatively, the online water injection device 11 is configured as a mixer, and the fuel enters the mixer at a predetermined flow rate; water is injected into the mixer through an atomizing nozzle at a set ratio, and is instantly mixed with the fuel to form an emulsion, and the mixed emulsion is injected into the fuel pipeline through the water injection nozzle 9.

[0039] Specifically, a sampling port 13 is provided between the static mixer 10 and the first three-way valve F3. The oil sample in the fuel pipeline is collected online from the sampling port 13 for analyzing the water content in the fuel. Since the sampled fuel has a low temperature, it is easy to cause the water in the air to liquefy. The sampled oil should be heated in a sealed sampling tube first, and then put into the sampling bottle for extraction after returning to room temperature, so as to minimize the influence of water in the air.

[0040] Specifically, it also includes a second three-way valve F4, a third three-way valve F5, a fourth three-way valve F6, a circulating water removal circuit and a circulating filtration circuit, the circulating water removal circuit includes an oil-water separator 6, and the circulating filtration circuit includes a first filter 7; The first end and the second end of the second three-way valve F4 are connected to the inlet end and the outlet end of the oil-water separator 6 respectively, and the third end of the second three-way valve F4 is connected to the third end of the first three-way valve F3; The first end, the second end and the third end of the third three-way valve F5 are connected to the outlet end of the oil-water separator 6 and the inlet end and the outlet end of the first filter 7 respectively; The first end and the second end of the fourth three-way valve F6 are connected to the outlet end of the first filter 7 and the oil return end of the oil supply tank 1 respectively.

[0041] It should be noted that, in the circulating water removal circuit, under room temperature conditions, the fuel in the fuel supply tank 1 is pumped out by the fuel supply pump 2, free water in the fuel is removed by the oil-water separator 6, and the fuel after water removal is returned to the fuel supply tank 1, thereby realizing the fuel water removal function through circulation.

[0042] The circulating filtration loop, under room temperature conditions, pumps out the fuel in the fuel supply tank 1 through the fuel supply pump 2, removes impurities in the fuel through the first filter 7, and returns the fuel after the impurities are removed to the fuel supply tank 1, thereby realizing the fuel filtering function through circulation; in order to prevent impurities from damaging the oil-water separator 6, the circulation does not pass through the oil-water separator 6.

[0043] In addition, the circulating refrigeration circuit pumps out the fuel in the fuel supply tank 1 through the fuel supply pump 2, absorbs the cooling capacity of the refrigeration device 4 through the heat exchanger 3, and returns the refrigerated fuel to the fuel supply tank 1, thereby realizing the fuel refrigeration function through circulation; in order to avoid damage to the first filter 7 and the oil-water separator 6 due to low temperature, the circulation also does not pass through the first filter 7 and the oil-water separator 6.

[0044] Specifically, it also includes an oil post-processing circuit, which includes a second filter 15, a fifth three-way valve F8, an oil return tank 19, an oil return valve F7 and an oil return pump 16; the outlet of the engine fuel accessory 14 is connected to the first end of the fifth three-way valve F8 through the second filter 15, and the second end and the third end of the fifth three-way valve F8 are respectively connected to the oil return tank 19 and the oil supply tank 1; the oil return tank 19, the oil return valve F7 and the oil return pump 16 are connected in sequence, the third end of the fourth three-way valve F6 is connected to the oil return tank 19, and the oil return pump 16 is respectively connected to the third end of the second three-way valve F4 and the third end of the first three-way valve F3; the oil return tank 19 is connected to a second drain valve 18.

[0045] The oil post-processing circuit collects the oil-water mixture after the freezing test through the return oil tank 19, pumps the mixture out through the return oil pump 16, removes free water in the fuel through the oil-water separator 6, and returns to the oil tank 19.

[0046] Specifically, the water injection nozzle 9 adopts an atomizing nozzle, and the sprayed liquid has a good atomization effect. In order to prevent the water at the water injection nozzle 9 from freezing and causing blockage at low temperatures, a certain ratio of oil-water emulsion can be injected online. Practice has proved that a certain flow rate of oil-water emulsion will not block the nozzle at low temperatures; the structure of the water injection nozzle 9 can also be designed to use a certain flow of normal temperature fuel and water to exchange heat at the nozzle to ensure that the water temperature at the nozzle is not lower than 0°C to avoid water freezing and blocking the nozzle.

[0047] For example, the volume of the oil supply tank 1 and the oil return tank 19 should be determined according to the test subject. In principle, the volume should not be less than 1.5 times the amount of fuel required for the entire icing test.

[0048] The filtering accuracy of the first filter 7 and the second filter 15 is not less than 5um, and the oil-water separator 6 can ensure that the moisture content in the oil supply device is reduced to below 90ppmV within a specified time (such as 4h) under normal temperature conditions.

[0049] The refrigeration device 4 can provide sufficient refrigeration power to ensure that the fuel in the fuel supply device is cooled to the required test temperature (such as -40°C) within a specified time (such as 4 hours).

[0050] The environmental temperature box can provide sufficient cooling power to ensure that the ambient temperature of the engine fuel accessory 14 is cooled to the required test temperature (eg, -40°C) within a specified time (eg, 4 hours).

[0051] Example 2 This embodiment also provides a fuel freezing test method based on online water injection. The fuel freezing test system based on online water injection can be divided into three parts: oil and water preparation stage, water injection test stage, and test post-processing stage. It includes: Oil and water preparation stage: S1: injecting fuel into the fuel supply tank 1, controlling and starting the fuel supply pump 2, switching the fuel supply device to the circulating filter loop to filter the fuel, and testing the fuel particle size; S2: After the fuel particle size test is qualified, the refrigeration device 4 is controlled to start, the fuel temperature at the oil side outlet of the heat exchanger 3 is controlled to be 29°C±3°C, and the water injection device is controlled to inject a predetermined amount of water or emulsion into the system through the water injection nozzle 9 to make the water content of the fuel in the system supersaturated; S3: Control the oil supply device to switch to the circulating water removal circuit to perform circulating water removal; sample every 1 hour, if the water content is 80ppm-90ppm, and the saturated water content of the fuel at 30°C is 68±5ppm, the predetermined target is met; S4: After the moisture content meets the predetermined target, the oil supply device is controlled to switch to the circulating refrigeration circuit to perform circulating refrigeration. At the same time, the environmental temperature box performs synchronous refrigeration, so that the working temperature of the fuel in the system and the inlet temperature of the engine fuel accessory 14 simultaneously reach the corresponding predetermined low temperature conditions; Water injection test phase: S5: Control the fuel supply device to switch to the fuel supply pressure regulating circuit, so that the fuel is supplied to the engine fuel accessory 14, and the fuel is returned from the engine fuel accessory 14 to the return oil tank 19, and the opening of the throttle valve is adjusted through closed-loop control to adjust the inlet pressure of the engine fuel accessory 14; S6: adjusting the engine fuel accessory 14 to a desired speed through a transmission device according to actual working conditions; S7: Control the oil supply device to switch to the oil-water mixed supply circuit, and adopt a fixed ratio control method to control the flow rate of water or emulsion injected by the online water injection device 11 to follow the change of the fuel supply amount in real time, so that the water or emulsion flow rate is proportional to the fuel supply flow rate, ensuring that the water content of the fuel inlet of the engine fuel accessory 14 is within the range of 290-330ppm; S8: During the test, the fuel inlet of the engine fuel accessory 14 is collected regularly for water detection to confirm that the water content of the fuel is within the range of 290 to 330 ppm; Post-test processing stage: S9: After the test, the online water injection device 11, the transmission device, the environmental temperature box, the refrigeration device 4 and the oil supply device are closed in sequence, and the oil return tank 19 is left to stand for several hours, and then the second drain valve 18 is opened to drain the water deposited at the bottom of the oil return tank 19; S10: Control to open the oil supply device, switch to the oil post-processing circuit, and separate the free water in the oil return tank 19 through the oil-water separator 6; S11: Sampling inspection. If the water content of the separated fuel meets the saturated water content condition at the temperature, the water removal is stopped and the fuel is returned to the fuel supply tank 1.

[0052] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A fuel icing test system based on online water injection, characterized in that: include: A fuel supply device, used for supplying fuel; An online water injection device (11) is connected to the oil supply device and is used to provide a predetermined amount of water or emulsion in real time according to the supply amount of the fuel, so as to mix with the fuel to form an oil-water mixture; A refrigeration device (4), connected to the fuel supply device, and used to cool the fuel supplied by the fuel supply device to a predetermined temperature; An environmental temperature box has an engine fuel accessory (14) built in it, the environmental temperature box provides an environmental condition of a predetermined temperature for the engine fuel accessory (14), and the inlet of the engine fuel accessory (14) is capable of receiving the oil-water mixture.

2. A fuel icing test system based on online water injection according to claim 1, characterized in that: The oil supply device comprises a circulating refrigeration circuit, wherein the circulating refrigeration circuit comprises an oil supply tank (1), an oil supply valve (F1), an oil supply pump (2), a heat exchanger (3), a flow meter (8) and a circulating pump (12) which are connected in sequence; the oil supply tank (1) is connected to a first drain valve (17); The heat exchanger (3) is connected to the refrigeration device (4); The fuel supply pump (2) is capable of pumping out the fuel in the fuel supply tank (1), absorbing the cooling capacity of the refrigeration device (4) through the heat exchanger (3), and the refrigerated fuel is returned to the fuel supply tank (1) through the circulation pump (12).

3. A fuel icing test system based on online water injection according to claim 2, characterized in that: It also includes a pressure regulating circuit, which includes a regulating valve (F2) connected to the oil-side outlet of the heat exchanger (3), and the regulating valve (F2) is connected to the inlet end of the oil supply pump (2); the flow rate of bypass return oil to the inlet of the oil supply pump (2) can be controlled by the regulating valve (F2) to adjust the fuel supply pressure.

4. A fuel icing test system based on online water injection according to claim 2, characterized in that: The oil supply device further comprises an oil-water mixed supply circuit, wherein the oil-water mixed supply circuit comprises a static mixer (10), a circulation pump (12) and a first three-way valve (F3); The first end of the flow meter (8) is connected to the oil-side outlet of the heat exchanger (3); the online water injection device (11) is connected to a water injection nozzle (9); the second end of the flow meter (8), the water injection nozzle (9), the static mixer (10) and the first end of the first three-way valve (F3) are connected in sequence; the second end of the first three-way valve (F3) is connected to the inlet of the engine fuel accessory (14); the second end of the flow meter (8), the circulation pump (12) and the inlet of the engine fuel accessory (14) are connected in sequence; The online water injection device (11) can configure corresponding water or emulsion in real time according to the flow rate collected by the flow meter (8), and inject it into the fuel pipeline through the water injection nozzle (9), and mix it with the fuel in the static mixer (10). The mixed oil-water mixture is circulated through the circulation pump (12) for secondary mixing and then supplied to the engine fuel accessory (14). The circulation pump (12) is used to crush the water droplets that are not fully mixed to promote the secondary mixing with the oil so as to mix them evenly.

5. A fuel icing test system based on online water injection according to claim 4, characterized in that: The online water injection device (11) is configured to inject a predetermined amount of fuel and a predetermined amount of water into an emulsion proportioning tank in advance, and mix the oil and water evenly by vibration and stirring. When the mixture is ready for use, the amount of the mixture is controlled by a metering pump and injected into the fuel pipeline through the water injection nozzle (9); Alternatively, the online water injection device (11) is configured as a mixer, and the fuel enters the mixer at a predetermined flow rate; water is injected into the mixer at a set ratio through an atomizing nozzle, and is instantly mixed with the fuel to form an emulsion, and the mixed emulsion is injected into the fuel pipeline through the water injection nozzle (9).

6. A fuel icing test system based on online water injection according to claim 4, characterized in that: A sampling port (13) is provided between the static mixer (10) and the first three-way valve (F3).

7. A fuel icing test system based on online water injection according to claim 4, characterized in that: It also includes a second three-way valve (F4), a third three-way valve (F5), a fourth three-way valve (F6), a circulating water removal circuit and a circulating filtration circuit, wherein the circulating water removal circuit includes an oil-water separator (6), and the circulating filtration circuit includes a first filter (7); The first end and the second end of the second three-way valve (F4) are respectively connected to the inlet end and the outlet end of the oil-water separator (6), and the third end of the second three-way valve (F4) is connected to the third end of the first three-way valve (F3); The first end, the second end and the third end of the third three-way valve (F5) are connected to the outlet end of the oil-water separator (6) and the inlet end and the outlet end of the first filter (7) respectively; The first end and the second end of the fourth three-way valve (F6) are respectively connected to the outlet end of the first filter (7) and the oil return end of the oil supply tank (1).

8. A fuel icing test system based on online water injection according to claim 7, characterized in that: It also includes an oil post-processing circuit, the oil post-processing circuit including a second filter (15), a fifth three-way valve (F8), an oil return tank (19), an oil return valve (F7) and an oil return pump (16); The outlet of the engine fuel accessory (14) is connected to the first end of the fifth three-way valve (F8) through the second filter (15), and the second end and the third end of the fifth three-way valve (F8) are connected to the oil return tank (19) and the oil supply tank (1) respectively; The oil return tank (19), the oil return valve (F7) and the oil return pump (16) are connected in sequence; the third end of the fourth three-way valve (F6) is connected to the oil return tank (19); the oil return pump (16) is respectively connected to the third end of the second three-way valve (F4) and the third end of the first three-way valve (F3); the oil return tank (19) is connected to a second drain valve (18).

9. The fuel icing test system based on online water injection according to claim 1, characterized in that: The water injection nozzle (9) is an atomizing nozzle, and the atomization effect of the sprayed liquid is good.

10. A fuel freezing test method based on online water injection, using the fuel freezing test system based on online water injection according to any one of claims 1 to 6, characterized in that: include: Oil and water preparation stage: S1: injecting fuel into the fuel supply tank (1), controlling the start of the fuel supply pump (2), switching the fuel supply device to the circulating filter loop to filter the fuel, and testing the fuel particle size; S2: After the fuel particle size test is qualified, the refrigeration device (4) is controlled to start, the fuel temperature at the oil side outlet of the heat exchanger (3) is controlled to be 29°C±3°C, and the water injection device is controlled to inject a predetermined amount of water or emulsion into the system through the water injection nozzle (9) to make the water content of the fuel in the system supersaturated; S3: Control the oil supply device to switch to the circulating water removal circuit to perform circulating water removal; sample every 1 hour, if the water content is 80ppm-90ppm, and the saturated water content of the fuel at 30°C is 68±5ppm, the predetermined target is met; S4: After the water content meets the predetermined target, the oil supply device is controlled to switch to the circulating refrigeration circuit to perform circulating refrigeration, and at the same time, the environmental temperature box performs synchronous refrigeration, so that the working temperature of the fuel in the system and the inlet temperature of the engine fuel accessory (14) simultaneously reach the corresponding predetermined low temperature conditions; Water injection test phase: S5: Controlling the oil supply device to switch to the oil supply pressure regulating circuit, so that the fuel is supplied to the engine fuel accessory (14), and the fuel is returned from the engine fuel accessory (14) to the oil return tank (19), and the opening of the throttle valve is adjusted through closed-loop control to adjust the inlet pressure of the engine fuel accessory (14); S6: adjusting the engine fuel accessory (14) to a desired rotation speed through a transmission device according to actual working conditions; S7: Controlling the oil supply device to switch to the oil-water mixed supply circuit, using a fixed ratio control method, controlling the flow rate of water or emulsion injected by the online water injection device (11) to follow the change of the fuel supply flow rate in real time, so that the water or emulsion flow rate is proportional to the fuel supply flow rate, ensuring that the water content of the fuel inlet of the engine fuel accessory (14) is within the range of 290 to 330 ppm; S8: During the test, the fuel inlet of the engine fuel accessory (14) is collected at regular intervals for water testing to confirm that the water content of the fuel is within the range of 290 to 330 ppm; Post-test processing stage: S9: After the test is completed, the online water injection device (11), the transmission device, the environmental temperature box, the refrigeration device (4) and the oil supply device are closed in sequence, and the oil return tank (19) is left to stand for several hours, and then the second drain valve (18) is opened to drain the water deposited at the bottom of the oil return tank (19); S10: controlling the oil supply device to start, switching to the oil post-processing circuit, and separating free water in the oil return tank (19) through the oil-water separator (6); S11: Sampling and inspection. If the water content of the separated fuel meets the saturated water content condition at the temperature, the water removal is stopped and the fuel is returned to the fuel supply tank (1).

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