Anti-freezing aviation fuel low-temperature test system and method

Abstract

The invention belongs to the technical field of aircraft fuel accessory low-temperature tests, and discloses an anti-freezing aircraft fuel low-temperature test system and method, and the system comprises a fuel tank, a refrigerating unit, a heat exchanger, a self-circulation system, an inlet manual valve, a fuel supply pump and an outlet manual valve. A bottom outlet of the oil tank is connected with an inlet of a tested product through an inlet manual valve and an oil supply pump; an outlet of the tested product is connected with a top inlet of the oil tank through an outlet manual valve; wherein the fuel tank is independently wrapped by a thermal insulation material, the fuel tank is circularly connected with the refrigerating unit through the self-circulation system, the heat exchanger is arranged in the refrigerating unit, and the self-circulation system and the heat exchanger work at the same time, so that the temperature of aviation fuel in the fuel tank is reduced to be below the fuel solidification temperature under the state that the aviation fuel always keeps flowing. Fuel oil condensation is prevented, the dry grinding risk of a tested piece is reduced, and reliable development of a low-temperature test is realized.

Description

Technical Field

[0001] This invention belongs to the field of low-temperature testing technology for aviation fuel accessories, and relates to a system and method for low-temperature testing of aviation fuel, specifically a low-temperature testing system and method for antifreeze aviation fuel. Background Technology

[0002] During startup and flight, aircraft are subject to dynamic changes in their surrounding environment, with temperatures sometimes dropping below -50°C. To ensure the reliability of aircraft in low-temperature environments, aviation fuel accessories, as the power source for aircraft engines, need to maintain reliable performance in such environments. Low-temperature tests are required to verify the performance of aviation fuel accessories in low-temperature environments, thereby ensuring that the aircraft will not experience functional failures due to low temperatures during mission execution.

[0003] In cryogenic testing of aviation fuel accessories, aviation fuel, specifically No. 3 jet fuel, is typically used as the test medium. This testing usually requires a refrigeration unit to cool the aviation fuel to below -50°C to simulate actual operating conditions at low temperatures. However, the freezing point of aviation fuel is generally between -40°C and -47°C. Using a cryogenic refrigeration unit would reduce the fluidity of the aviation fuel, making it prone to solidification, pipe blockage, and other problems, thus preventing the cryogenic test from being conducted normally.

[0004] To ensure the normal conduct of the test and prevent the test specimen from dry grinding due to the solidification of fuel in the fuel tank of the refrigeration system, which could damage the test specimen and affect the test results, and in accordance with the principle of saving manufacturing costs, the refrigeration system was improved to meet the normal operation of the low-temperature test. Summary of the Invention

[0005] This invention provides a cryogenic testing system and method for antifreeze aviation fuel, which can prevent fuel condensation during cryogenic testing, reduce the risk of dry friction of test specimens, and enable reliable conduct of cryogenic testing. It also has high compatibility, good economic benefits, and is easy to promote.

[0006] The technical solution of the present invention is as follows: A cryogenic testing system for antifreeze aviation fuel includes a fuel tank, a refrigeration unit, a heat exchanger, a self-circulation system, an inlet manual valve, a fuel supply pump, and an outlet manual valve. The bottom outlet of the fuel tank is connected to the inlet of the test product via the inlet manual valve and the fuel supply pump. The outlet of the test product is connected to the top inlet of the fuel tank via the outlet manual valve. The fuel tank is separately wrapped with insulation material. The fuel tank is circulated with the refrigeration unit via the self-circulation system. The heat exchanger is located inside the refrigeration unit. The self-circulation system and the heat exchanger work simultaneously to keep the temperature of the aviation fuel in the fuel tank below the fuel freezing point while maintaining constant flow.

[0007] Furthermore, the self-circulation system includes a circulation system manual valve, a circulation system oil filter, and a circulation system oil supply pump. The bottom of the oil tank is also equipped with a self-circulation outlet. The self-circulation outlet of the oil tank first passes through the circulation system manual valve, then through the circulation system oil filter, and finally through the circulation system oil supply pump before connecting to the bottom outlet of the oil tank.

[0008] Furthermore, an inlet oil filter is also installed between the inlet manual valve and the oil supply pump.

[0009] Furthermore, an inlet pressure transmitter and an inlet thermometer are installed between the oil supply pump and the test product. The outlet of the oil supply pump is also connected to the top inlet of the oil tank through a bypass oil line, and an overflow valve is installed on the bypass oil line.

[0010] Furthermore, an outlet pressure transmitter and an outlet thermometer are also installed between the test product and the outlet manual valve.

[0011] Furthermore, an outlet flow meter and an outlet oil filter are also installed between the outlet manual valve and the top inlet of the oil tank.

[0012] A method for cryogenic testing of antifreeze aviation fuel, comprising the following steps: S1, keep the inlet manual valve and outlet manual valve closed, and stop the oil supply pump; S2, open and run the self-circulation system to ensure that the aviation fuel in the fuel tank and the low-temperature refrigeration medium in the heat exchanger have sufficient heat exchange and that the aviation fuel in the fuel tank always remains in a flowing state. S3, open the inlet manual valve and the outlet manual valve, start the fuel supply pump, so that aviation fuel enters the test product inlet from the fuel tank, and then returns to the fuel tank from the test product outlet; S4 completes the test of the product by measuring the changes in aviation fuel before and after it enters and flows out of the product.

[0013] Furthermore, in S2, the aviation fuel in the tank is cooled to below 55°C before entering S3.

[0014] The beneficial effects of this invention are as follows: 1. This invention can prevent fuel condensation and reduce the risk of dry grinding of the test specimen in low-temperature tests, thus enabling reliable low-temperature testing.

[0015] 2. Compared with the original test system, the present invention has fewer new mechanical parts, which can save a lot of test equipment reconstruction costs. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a diagram of the experimental system of the present invention.

[0018] Figure 2 This is a schematic diagram of the conventional low-temperature testing system of the present invention.

[0019] Figure 3 This is a schematic diagram of the improved low-temperature testing system of the present invention.

[0020] Explanation of reference numerals in the attached figures: 1—Oil tank, 2—Refrigeration unit, 3—Inlet manual valve, 4—Inlet oil filter, 5—Oil supply filter, 6—Relief valve, 7—Inlet pressure transmitter, 8—Inlet thermometer, 9—Outlet pressure transmitter, 10—Outlet thermometer, 11—Outlet manual valve, 12—Outlet flow meter, 13—Outlet oil filter, 14—Circulation system manual valve, 15—Circulation system oil filter, 16—Circulation system oil supply pump, 17—Heat exchanger. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0023] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0025] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0027] First embodiment: A cryogenic testing system for antifreeze aviation fuel includes a fuel tank 1, a refrigeration unit 2, a heat exchanger 17, a self-circulation system, an inlet manual valve 3, a fuel supply pump 5, and an outlet manual valve 11. The bottom outlet of the fuel tank 1 is connected to the inlet of the test product through the inlet manual valve 3 and the fuel supply pump 5, and the outlet of the test product is connected to the top inlet of the fuel tank 1 through the outlet manual valve 11. The fuel tank 1 is separately wrapped with insulation material. The fuel tank 1 is circulatedly connected to the refrigeration unit 2 through the self-circulation system. The heat exchanger 17 is located inside the refrigeration unit 2. The self-circulation system and the heat exchanger 17 work simultaneously to keep the aviation fuel in the fuel tank 1 flowing while reducing the temperature below the fuel freezing point.

[0028] The self-circulation system includes a circulation system manual valve 14, a circulation system oil filter 15, and a circulation system oil supply pump 16. The bottom of the oil tank 1 is also provided with a self-circulation outlet. The self-circulation outlet of the oil tank 1 first passes through the circulation system manual valve 14, then through the circulation system oil filter 15, and finally through the circulation system oil supply pump 16 before connecting to the bottom outlet of the oil tank 1.

[0029] An imported oil filter 4 is also installed between the imported manual valve 3 and the oil supply pump 5.

[0030] An inlet pressure transmitter 7 and an inlet thermometer 8 are also provided between the oil supply pump 5 and the test product. The outlet of the oil supply pump 5 is also connected to the top inlet of the oil tank 1 through a bypass oil line, and an overflow valve 6 is provided on the bypass oil line.

[0031] An outlet pressure transmitter 9 and an outlet thermometer 10 are also installed between the test product and the outlet manual valve 11.

[0032] An outlet flow meter 12 and an outlet oil filter 13 are also provided between the outlet manual valve 11 and the top inlet of the oil tank 1.

[0033] A method for cryogenic testing of antifreeze aviation fuel, comprising the following steps: S1, keep the inlet manual valve 3 and the outlet manual valve 11 closed, and stop the oil supply pump 5; S2, open and run the self-circulation system to ensure that the aviation fuel in tank 1 and the low-temperature refrigeration medium in heat exchanger 17 can fully exchange heat and keep the aviation fuel in tank 1 in a flowing state. S3, open the inlet manual valve 3 and the outlet manual valve 11, start the fuel supply pump 5, so that aviation fuel enters the test product inlet from the fuel tank 1, and then returns to the fuel tank 1 from the test product outlet; S4 completes the test of the product by measuring the changes in aviation fuel before and after it enters and flows out of the product.

[0034] In S2, the aviation fuel in fuel tank 1 is cooled to below 55°C before entering S3.

[0035] Second embodiment: This invention proposes a cryogenic testing system for antifreeze aviation fuel, which can prevent fuel condensation during cryogenic testing, reduce the risk of dry friction of test specimens, and enable reliable conduct of cryogenic testing. It also has high compatibility, good economic benefits, and is easy to promote.

[0036] A typical low-temperature testing system consists of a power distribution system, a circulating cooling system, a low-pressure air station, a testing apparatus ventilation system, an electrical control system, an oil replenishment system, a measurement system, a pressurized oil supply system, a fuel temperature control system, a filtration system, and a computer control system. Among these, the power distribution system, circulating water system, air system, and testing apparatus ventilation system form the basic supply system for the plant. The relationships between these systems are as follows: Figure 1 As shown.

[0037] 1) Measurement system: The measurement system includes pressure sensors, temperature sensors, flow meters, and measures temperature, pressure, and flow rate values ​​in real time.

[0038] 2) Boosting oil supply system: This control system is the core of the equipment. The system consists of an oil supply motor, etc.

[0039] 3) Fuel temperature control system: The ambient temperature control system consists of a refrigeration unit, fuel tank, etc.

[0040] 4) Electrical Control System: The electrical control box is the low-voltage control box for the equipment. A temperature controller is installed at the top of the control box, a control panel and printer interface are located in the middle, and a PLC is installed at the bottom. The PLC controller is used for the operation and control of the equipment's switching quantities; it is also used for the output of standard analog signals, generating a preset standard analog signal and outputting it to the controller.

[0041] 5) Computer control system: data acquisition and processing functions.

[0042] 6) Filtration system: used for filtering the cleanliness of the test medium, including oil filter, etc.

[0043] like Figure 2 The diagram shows the principle of a conventional aviation fuel cryogenic testing system. Fuel tank 1 is installed inside the refrigeration unit 2. The refrigeration unit 2 lowers the temperature of the aviation fuel in fuel tank 1 to below -50°C. When the temperature of the aviation fuel in fuel tank 1 reaches -50°C, the inlet manual valve 3 and the outlet manual valve 11 are opened, and the fuel supply pump 5 is started. The aviation fuel flows from fuel tank 1 through the inlet oil filter 4 and enters the inlet of the test product, then returns to fuel tank 1 from the outlet of the test product through the outlet flow meter 12 and the outlet oil filter. In actual operation, when the refrigeration unit lowers the temperature inside fuel tank 1 to -50°C, the aviation fuel in fuel tank 1 freezes because the freezing point of aviation fuel is usually in the range of -40°C to -47°C. The frozen aviation fuel loses its fluidity, making it impossible to supply aviation fuel to the inlet of the test product normally after the fuel supply pump 5 is started. This can easily lead to dry friction of the test product, making the test impossible to conduct normally.

[0044] To maintain the fluidity of fuel at low temperatures and prevent it from freezing, Figure 2 Perform as Figure 3 The improvements shown will prevent the aviation fuel under the refrigeration unit from freezing, ensuring the normal conduct of the test.

[0045] This invention modifies a conventional aviation fuel cryogenic testing system according to the following process: like Figure 3As shown, fuel tank 1 is removed from the refrigeration unit 2 and individually wrapped with insulation material to reduce heat exchange with the outside environment. A new heat exchanger 17 is added to refrigeration unit 2, which can lower the refrigerant in the heat exchanger to -55°C within the refrigeration unit 2. A new self-circulating system is also added, consisting of a circulation system manual valve 14, a circulation system oil filter 15, and a circulation system fuel supply pump 16. When the circulation system manual valve 14 is opened and the circulation system fuel supply pump 16 is started, the aviation fuel and refrigerant in fuel tank 1 fully exchange heat with the low-temperature refrigerant in heat exchanger 17. This ensures that the aviation fuel in fuel tank 1 remains in a flowing state during the small-scale refrigeration cycle, preventing freezing and maintaining a liquid state. When the temperature inside the fuel tank drops to -50℃, open the inlet manual valve 3 and the outlet manual valve 11, and start the fuel supply pump 5. Aviation fuel enters the test product inlet from the fuel tank 1 after being filtered by the inlet oil filter 4, and then returns to the fuel tank 1 from the outlet of the test product through the outlet flow meter 12 and the outlet oil filter.

[0046] The above improvements prevent aviation fuel from freezing during the refrigeration process, ensuring the normal conduct of low-temperature tests. Furthermore, the modifications are convenient, requiring fewer new mechanical parts and saving significant costs associated with rebuilding the testing equipment.

[0047] This invention solves the condensation problem in the aviation fuel refrigeration process by converting statically refrigerated aviation fuel into dynamically refrigerated aviation fuel, thereby reducing damage to the test product during low-temperature testing and improving the confidence level of low-temperature testing. This invention has been successfully applied to our company's low-temperature testing equipment, solving the low-temperature testing needs of some products.

[0048] During the test, the manual valve 14 of the circulation system must remain open. Adding the circulation system oil filter 15 to the circulation system can effectively improve the anti-pollution ability of the circulation system and prevent the circulation system oil supply pump 16 from being stuck or damaged by contaminants. The circulation system oil supply pump 16 should be selected with good low-temperature performance and a rust-proof coating on the surface. During the cooling process, the temperature of the circulation system oil supply pump 16 drops to below zero. After contacting the surrounding air, frost will form on the surface, which is prone to rust and affects the performance and life of the oil supply pump. The pipeline of the circulation system should be wrapped with insulation cotton to reduce energy loss during the cooling process and improve the cooling efficiency.

[0049] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A cryogenic testing system for antifreeze aviation fuel, characterized in that, The system includes an oil tank (1), a refrigeration unit (2), a heat exchanger (17), a self-circulation system, an inlet manual valve (3), an oil supply pump (5), and an outlet manual valve (11). The bottom outlet of the oil tank (1) is connected to the inlet of the test product through the inlet manual valve (3) and the oil supply pump (5). The outlet of the test product is connected to the top inlet of the oil tank (1) through the outlet manual valve (11). The oil tank (1) is wrapped separately with insulation material. The oil tank (1) is circulated with the refrigeration unit (2) through the self-circulation system. The heat exchanger (17) is located inside the refrigeration unit (2). The self-circulation system and the heat exchanger (17) work simultaneously so that the temperature of the aviation fuel in the oil tank (1) drops below the fuel solidification temperature while the fuel is always in a flowing state.

2. The anti-freezing aviation fuel cryogenic testing system according to claim 1, characterized in that, The self-circulation system includes a circulation system manual valve (14), a circulation system oil filter (15), and a circulation system oil supply pump (16). The bottom of the oil tank (1) is also provided with a self-circulation outlet. The self-circulation outlet of the oil tank (1) first passes through the circulation system manual valve (14), then through the circulation system oil filter (15), and finally through the circulation system oil supply pump (16) before connecting to the bottom outlet of the oil tank (1).

3. The anti-freezing aviation fuel cryogenic testing system according to claim 1, characterized in that, An inlet oil filter (4) is also provided between the inlet manual valve (3) and the oil supply pump (5).

4. The anti-freezing aviation fuel cryogenic testing system according to claim 1, characterized in that, An inlet pressure transmitter (7) and an inlet thermometer (8) are also provided between the oil supply pump (5) and the test product. The outlet of the oil supply pump (5) is also connected to the top inlet of the oil tank (1) through a bypass oil line. An overflow valve (6) is provided on the bypass oil line.

5. The anti-freezing aviation fuel cryogenic testing system according to claim 1, characterized in that, An outlet pressure transmitter (9) and an outlet thermometer (10) are also provided between the test product and the outlet manual valve (11).

6. The anti-freezing aviation fuel cryogenic testing system according to claim 1, characterized in that, An outlet flow meter (12) and an outlet oil filter (13) are also provided between the outlet manual valve (11) and the top inlet of the oil tank (1).

7. A method for cryogenic testing of antifreeze aviation fuel, characterized in that, Includes the following steps: S1, keep the inlet manual valve (3) and outlet manual valve (11) closed, and stop the oil supply pump (5); S2, open and run the self-circulation system to allow the aviation fuel in the fuel tank (1) to fully exchange heat with the low-temperature refrigeration medium in the heat exchanger (17), and to keep the aviation fuel in the fuel tank (1) in a flowing state. S3, open the inlet manual valve (3) and the outlet manual valve (11), start the fuel supply pump (5), so that aviation fuel enters the test product inlet from the fuel tank (1) and then returns to the fuel tank (1) from the test product outlet; S4 completes the test of the product by measuring the changes in aviation fuel before and after it enters and flows out of the product.

8. According to the method for testing the low temperature of antifreeze aviation fuel as described in claim 7, in S2, the aviation fuel in the fuel tank (1) is reduced to below 55°C before entering S3.

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