Fuel tank oil level monitoring method for combustion test

Abstract

The present invention relates to the field of fuel tank combustion test, and specifically to a fuel tank oil quantity monitoring method for combustion test, comprising: installing the fuel tank to be tested into the combustion test area, and keeping the oil inlet pipeline, oil outlet pipeline and air outlet pipeline of the fuel tank to be tested in a preset state, simulating the actual use state of the fuel tank to be tested on an aircraft; inserting a U-shaped monitoring tube into the fuel tank to be tested, and keeping the liquid level in the monitoring tube at the same height as the liquid level in the fuel tank to be tested, allowing one end of the monitoring tube to extend to the inner bottom surface of the fuel tank to be tested, and allowing the other end of the monitoring tube to always be located above the liquid level in the fuel tank to be tested; photographing the liquid level position image of the monitoring tube by a camera, and displaying the page position image fuel supply monitoring observation. The present invention can continuously monitor the oil volume of a windowless fuel tank during a combustion test.

Description

Technical Field

[0001] The invention relates to the field of fuel tank combustion tests, and in particular to a fuel tank oil quantity monitoring method for combustion tests. Background Art

[0002] The fuel tank of an aircraft can be made of aluminum alloy, oil-proof material or stainless steel to provide power oil or lubricating oil for the flight of the aircraft. When a fire occurs on an aircraft, whether the fuel tank storing power oil or lubricating oil can safely supply oil to various components is related to whether the emergency treatment measures of the aircraft can be carried out effectively. Therefore, it is necessary to conduct a combustion test on the fuel tank on the aircraft to measure the combustion performance of the fuel tank, making the combustion test of the fuel tank on the aircraft increasingly important.

[0003] During the combustion test of the fuel tank, it is necessary to keep the fuel tank filled with oil at all times to avoid fire or explosion caused by continuing the combustion test without oil. Therefore, it is necessary to observe whether there is oil in the fuel tank in real time during the combustion test. However, the fuel tanks on some aircraft are not equipped with windows for observing the oil level. In this case, a liquid level sensor needs to be installed in the fuel tank to detect the oil level in the tank. In order to meet the needs of special environments, the liquid level sensors currently used include high temperature resistant, ultrasonic, laser, capacitive, radar and impedance sensor products designed for special environmental needs. These sensor products are designed to have outstanding measurement effects under a certain specific parameter condition.

[0004] However, in the combustion test of the fuel tank, the sensor needs to meet the conditions of high temperature, high pressure and long-term durability at the same time in order to accurately measure the oil amount. When using the above-mentioned sensor to detect the oil amount during the combustion test of the fuel tank, it is easy to be damaged and unable to accurately detect the oil amount, resulting in the inability to continuously monitor the oil amount during the entire combustion test. Summary of the invention

[0005] The present invention aims to provide a method for monitoring the oil quantity in an oil tank for a combustion test, so as to solve the problem of discontinuous oil quantity monitoring.

[0006] The fuel tank oil quantity monitoring method for combustion test in this scheme includes the following steps:

[0007] Step 1, installing the oil tank to be tested in the combustion test area, and keeping the oil inlet pipeline, oil outlet pipeline and gas outlet pipeline of the oil tank to be tested in a preset state according to the test process;

[0008] Step 2, insert a U-shaped monitoring tube into the oil tank to be tested, and keep the liquid level in the monitoring tube at the same height as the liquid level in the oil tank to be tested, so that one end of the monitoring tube extends to the inner bottom surface of the oil tank to be tested, and the other end of the monitoring tube is always located above the liquid level in the oil tank to be tested;

[0009] Step 3, photographing the liquid level position image of the monitoring tube through a camera, and displaying the page position image for oil supply monitoring observation.

[0010] The beneficial effects of this program are:

[0011] When conducting a combustion test on the oil tank to be tested, the inserted monitoring tube is synchronized with the air pressure and liquid level height in the oil tank to be tested, so that the liquid level in the oil tank without a window can be quickly checked in real time. The monitoring tube has no electronic components and circuits that are sensitive to temperature and air pressure, and can accurately reflect the liquid level in the oil tank to be tested under long-term high temperature and high pressure environment. It is not easy to be damaged, and the measurement process is more continuous. Due to the high temperature of the combustion test, even if protection is provided around the test area, the temperature of the surrounding air is still relatively high. The liquid level position image is obtained by shooting for display, and there is no need to get close to view the liquid level position, which is safer and can accurately record the changes in the liquid level in the monitoring tube for subsequent tracing.

[0012] Furthermore, in step 1, the air pressure and temperature values ​​on the oil inlet pipeline, the oil outlet pipeline and the air outlet pipeline are detected respectively and displayed during oil quantity monitoring.

[0013] The beneficial effect is that a sufficient amount of oil can be maintained in the oil tank to be tested during the early stage of the test process.

[0014] Furthermore, in step 3, a liquid level position image is captured according to a preset frequency, and the liquid level height on the liquid level position image is identified and displayed.

[0015] The beneficial effects are: taking images of the liquid level position at a preset frequency to avoid wasting resources due to ineffective monitoring when the liquid level does not change while taking pictures continuously, identifying the liquid level height for display, which is more intuitive, and recording the changes in the liquid level in the monitoring tube to facilitate subsequent analysis of the liquid level in the U-shaped monitoring tube.

[0016] Furthermore, the method also includes step 4, in which a fiber optic sensor is installed in the oil tank to be tested and immersed in the oil of the oil tank to be tested, and the position corresponding to the oil temperature and air temperature in the oil tank to be tested is monitored on the fiber optic sensor as the liquid level.

[0017] The beneficial effect is: by setting up an optical fiber sensor to detect the oil temperature and air temperature in the test tank, because there is a certain difference between the oil temperature and air temperature in the test tank, and the liquid level changes greatly when the oil in the test tank boils, the oil level can be accurately, quickly and timely monitored according to the temperature values ​​at different points on the optical fiber sensor.

[0018] Furthermore, in step 1, the test process includes a first process and a second process, and the duration of the first process is shorter than the duration of the second process;

[0019] In the step 4, the liquid level of the oil tank to be tested in the first process is monitored by the monitoring tube, and the liquid level of the oil tank to be tested in the second process is monitored by the optical fiber sensor.

[0020] The beneficial effect is that the liquid level of the combustion test under different processes is monitored respectively by the monitoring tube and the optical fiber sensor, the liquid level monitoring is performed according to the test requirements, and the accuracy of the liquid level monitoring is improved.

[0021] Furthermore, in step 1, the first process is a process of maintaining a stable liquid level in the oil tank to be tested. When the test process is the first process, the oil inlet and outlet pipelines of the oil tank to be tested are kept in an open state, and the air outlet pipeline is kept in a closed state;

[0022] The second process is the dry burning process of the oil tank to be tested. When the test process is the second process, the oil inlet pipeline and the oil outlet pipeline of the oil tank to be tested are kept in a closed state, and the air outlet pipeline is kept in an open state.

[0023] The beneficial effect is: since the oil level changes greatly when the oil in the tested oil tank boils, the test process is combined with the liquid level monitoring in the test. The liquid level in the first process is monitored through the monitoring tube, and the observation is more intuitive, which can ensure that the liquid level in the tested oil tank is stably maintained at a certain value. In the second process, the optical fiber sensor detects the oil temperature and air temperature as the liquid level, which can accurately and timely monitor the oil level during dry burning.

[0024] Furthermore, the method further includes step 5, identifying the position information of the liquid level height on the liquid level position image, calculating the adjustment amount of the shooting position according to the difference between the position information and the initial position of the camera, and adjusting the shooting position according to the adjustment amount.

[0025] The beneficial effect is that the shooting position is judged and then adjusted to ensure that the corresponding liquid level position image and the clarity of the liquid level position image can be captured, thereby improving the accuracy of subsequent analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flowchart of a first embodiment of a method for monitoring the fuel level in a fuel tank for a combustion test;

[0027] Figure 2 This is a front view of a fuel tank fuel level monitoring device for a combustion test in the first embodiment of the fuel tank fuel level monitoring method for a combustion test;

[0028] Figure 3 for Figure 2 Schematic diagram of the installation structure of the fuel tank oil quantity monitoring device used in the combustion test during the test process. DETAILED DESCRIPTION

[0029] The following is further explained in detail through specific implementation methods.

[0030] The reference numerals in the drawings of the specification include: air pressure pipe 1, oil pipe 2, oil absorber 3, liquid level pipe 4, optical fiber sensor 5, wind shield 6, mounting frame 7, mounting plate 8, bracket 9, telescopic column 10, burner 11.

[0031] Embodiment 1

[0032] In order to realize the fuel tank oil level monitoring method for combustion test, the present embodiment 1 also discloses a fuel tank oil level monitoring device for combustion test, such as Figure 2 and Figure 3 As shown, it includes a U-shaped monitoring tube, which is installed through a through hole opened on the top of the oil tank to be tested. The gap between the monitoring tube and the through hole is sealed. The U-shaped monitoring tube includes a liquid level tube 4, an air pressure tube 1 and an oil pipe 2. The air pressure tube 1 and the oil pipe 2 can be made of existing stainless steel materials. The liquid level tube 4 is arranged in the vertical direction. The length of the liquid level tube 4 is equal to the height inside the oil tank to be tested. The bottom end of the liquid level tube 4 is flush with the inner bottom surface of the oil tank to be tested. The liquid level tube 4 is located outside the combustion test area where the oil tank to be tested burns.

[0033] One end of the air pressure tube 1 is bonded to the top of the liquid level tube 4, and the other end of the air pressure tube 1 can extend into the oil tank to be tested and is located above the liquid level in the oil tank to be tested. The height of the air pressure tube 1 extending from the top of the liquid level tube 4 is 10cm-18cm; the air pressure tube 1 is connected to an oil absorber 3, and the oil absorber 3 can use an existing small air pump. The air suction pipe of the air pump is bonded to the air pressure tube 1 and connected to the air pressure tube 1. The liquid level tube 4, the air pressure tube 1 and the oil pipe 2 form a U-shaped outer contour.

[0034] One end of the oil pipe 2 is bonded to the bottom end of the liquid level tube 4, and the other end of the oil pipe 2 can extend into the oil tank to be tested and is located within the liquid level in the oil tank to be tested, that is, the other end of the oil pipe 2 is always located below the oil surface in the oil tank to be tested, and the distance between the ends of the air pressure tube 1 and the oil pipe 2 located in the oil tank to be tested is equal to the depth in the oil tank to be tested. The height of the oil pipe 2 extending from the top of the oil tank to be tested is 8cm-15cm, and the air pressure tube 1 is located above the oil pipe 2.

[0035] It includes a plurality of windshields 6, and three windshields 6 can be provided, and the windshields 6 enclose a combustion test area. A fixing seat for limiting the air pressure pipe 1 and the oil pipe 2 is welded on the top of the windshield 6, and two U-shaped openings are provided on the limiting seat, and the opening direction of the U-shaped openings is facing the horizontal direction. An elastic layer is bonded on the inner wall of the U-shaped opening, and the spacing of the elastic layer surface is smaller than the diameter of the air pressure pipe 1 or the oil pipe 2. A mounting frame 7 for placing the oil tank to be tested is welded on the windshield 6, and a mounting plate 8 for placing the oil tank to be tested is welded on the mounting frame 7. The area of ​​the mounting plate 8 is larger than the main plane area of ​​the oil tank to be tested. A hanging ring for hanging the oil tank to be tested is fixed on the mounting plate 8 by screws, and the hanging ring is U-shaped. A bracket 9 is welded to the bottom of the windshield 6. The bracket 9 is L-shaped. A telescopic column 10 is installed on the bracket 9. The telescopic column 10 is in an empty sleeve manner to achieve the purpose of telescoping and is fixed after the length is extended or retracted by an adjusting bolt. A burner 11 for the combustion test of the oil tank to be tested is fixedly installed on the bracket 9. The burner 11 is aligned with the bottom of the oil tank to be tested, and the burner 11 is installed on the top of the burner 11 by screws.

[0036] It also includes an optical fiber temperature sensor extending to the bottom surface of the oil tank to be tested. The optical fiber temperature sensor can use existing products, such as THR-NS-1084A or other sensors that can meet the temperature requirements of the combustion test of the oil tank to be tested. The optical fiber temperature sensor signal is connected to the background processor, and the background processor can be a background PC computer. The optical fiber temperature sensor is used to detect the oil temperature and air temperature in the oil tank to be tested. The optical fiber temperature sensor measures the oil temperature and air temperature through different point temperatures. After the optical fiber temperature sensor detects the temperature, it can check the temperature at different positions, and judge the accurate liquid level in the oil tank to be tested based on the difference in oil temperature and air temperature. The temperature measurement principle of the optical fiber temperature sensor is existing and will not be repeated here.

[0037] The optical fiber temperature sensor is bonded to the outer wall of the end of the oil pipe 2 located on the side of the oil tank to be tested, the optical fiber sensor 5 is bonded to the outer wall of the end of the air pressure pipe 1 located on the side of the oil tank to be tested, and the optical fiber temperature sensor is located between the oil pipe 2 and the air pressure pipe 1.

[0038] Fuel tank fuel level monitoring method for combustion tests, such as Figure 1 As shown, the following steps are included:

[0039] Step 1, install the oil tank to be tested into the combustion test area, and keep the oil inlet pipeline, oil outlet pipeline and air outlet pipeline of the oil tank to be tested in a preset state according to the test process. The test process includes a first process and a second process. The duration of the first process is less than the duration of the second process. The duration of the first process is five minutes, and the duration of the second process is ten minutes.

[0040] The first process is to maintain the stability of the liquid level in the oil tank to be tested. When the test process is the first process, the oil inlet pipeline of the oil tank to be tested ( Figure 3 The oil inlet and outlet pipes ( Figure 3 The oil inlet on the upper part is in the open state, and the air outlet ( Figure 3 The first process is the preset state that the exhaust on the test tank is in a closed state; the second process is the dry burning process of the test tank. When the test process is the second process, the oil inlet and outlet pipelines of the test tank are kept in a closed state and the outlet pipeline is kept in an open state. The duration of the first process can ensure that the oil in the test tank maintains a stable liquid level when boiling, and the duration of the second process can fully test the performance of the test tank in the dry burning state after boiling, improve the accuracy of the combustion test results of the test tank, and will not waste too much test time.

[0041] The existing pressure sensors are used to detect the air pressure values ​​on the oil inlet pipeline, the oil outlet pipeline and the air outlet pipeline, and the temperature sensors are used to detect the temperature values, and these are displayed during oil quantity monitoring.

[0042] Step 2, insert a U-shaped monitoring tube into the oil tank to be tested, and keep the liquid level in the monitoring tube at the same height as the liquid level in the oil tank to be tested, let one end of the monitoring tube extend to the inner bottom surface of the oil tank to be tested, and let the other end of the monitoring tube always be above the liquid level in the oil tank to be tested, that is, monitor the liquid level of the oil tank to be tested during the first process through the monitoring tube. Ignite the oil tank to be tested for a combustion test. Within five minutes after ignition, keep the oil inlet and oil outlet pipelines in the open state and the gas outlet pipeline in the closed state. Within ten minutes after ignition for five minutes for the combustion test, keep the oil inlet and oil outlet pipelines in the open state and the gas outlet pipeline in the closed state.

[0043] Step 3, photographing the liquid level position image of the monitoring tube by a camera. The camera can use an existing high-temperature resistant camera to photograph the liquid level position image according to a preset frequency. The preset frequency is set according to actual needs. For example, the preset frequency is set to photograph the liquid level position image once every ten seconds. The page position image is displayed on the background display to monitor and observe the oil supply. The camera sends the liquid level position image to the background processor. The processor is a PC host equipped with an existing image processing program or software. The processor identifies the liquid level height on the liquid level position image and displays the liquid level height.

[0044] Step 4, by installing the optical fiber sensor 5 in the oil tank to be tested, the optical fiber sensor 5 extends into the oil tank to be tested through the same installation position as the monitoring tube, the optical fiber sensor 5 does not contact the monitoring tube, and the optical fiber sensor 5 is immersed in the oil in the oil tank to be tested. The position corresponding to the oil temperature and air temperature in the oil tank to be tested is monitored on the optical fiber sensor 5 as the liquid level, that is, the boundary point between the oil temperature and the air temperature is the liquid level. Since there is a certain difference between the oil temperature and the air temperature in the oil tank to be tested, the optical fiber sensor 5 extends into the oil in the oil tank to be tested, and the temperature at different depths of the oil tank to be tested is detected by the optical fiber sensor 5. The liquid level of the oil can be judged according to the position of the difference between the oil temperature and the air temperature, that is, the liquid level of the oil tank to be tested during the second process is monitored by the optical fiber sensor 5.

[0045] The method of this embodiment, when conducting a combustion test on the test oil tank, because the oil inlet and oil outlet processes of the oil tank are maintained in the first process, the air outlet is closed, and the oil inlet and oil outlet can keep the oil level stable, so that when the oil tank is rapidly heated up and boils, the oil is liquefied due to boiling, and the increased air pressure in the oil tank keeps the liquid level in the monitoring tube the same as that in the oil tank, so as to visually observe the liquid level in the oil tank; the oil tank is allowed to continue the combustion of the second process, the oil inlet and oil outlet are closed and the air outlet is opened, the oil tank is in a dry burning state, the boiling and liquefaction process continues to intensify, the oil will also churn violently, opening the air outlet can reduce the speed of the air pressure increase, and thus the monitoring tube will not be able to monitor the liquid level in time, quickly and accurately. At this time, by combining the optical fiber sensor 5 to detect the temperature in the oil tank, the liquid level in the oil tank can be accurately, quickly and timely monitored. The liquid level of the oil tank to be tested without a window can be quickly checked in real time at different test processes. The monitoring tube has no electronic components and circuits that are sensitive to temperature and air pressure. It is not easily disturbed by temperature and air pressure in the durability environment of the combustion test. It can accurately reflect the liquid level in the oil tank to be tested under high temperature and high pressure environment, is not easily damaged, and the measurement process is more continuous.

[0046] When observing the liquid level height in the fuel tank during the combustion test, it is generally done through the window on the fuel tank. For the observation of the liquid level height in the fuel tank without a window, in the process of research and development to solve the problem, it is easy to think of selecting a sensor that can meet the requirements of the use environment to detect the liquid level height during the fuel tank combustion test with the sensor, which is more intuitive and simple. However, during the fuel tank combustion test of this embodiment, due to the long test time, the sudden changes in temperature and air pressure are more and irregular, and the changes in temperature and air pressure inside the fuel tank cannot be pre-designed. When the temperature and air pressure inside the fuel tank and their changes exceed the maximum limit that the sensor can tolerate, the sensor is easily damaged, thereby affecting the observation of the oil level in the fuel tank, which is not conducive to the continuous and accurate conduct of the test. Therefore, the monitoring method of this embodiment, by setting a monitoring tube with the same air pressure and liquid level as the fuel tank, will not be disturbed by the changes in temperature and air pressure, and synchronously displays the oil volume in the fuel tank outside the fuel tank, and can monitor the oil volume in real time for a long time under the conditions of the combustion test and the flow of oil in the fuel tank, so as to maintain the continuity of the fuel tank combustion test and the accuracy of the test results.

[0047] Embodiment 2

[0048] The difference from the first embodiment is that it also includes step 5, identifying the position information of the liquid level height on the liquid level position image, the position information is the height of the liquid level in the monitoring tube, and calculating the adjustment amount of the shooting position according to the difference between the position information and the initial position of the camera, the difference is the height difference between the center of the camera lens and the liquid level, when the difference between the position information and the initial position of the camera is greater than the threshold, the threshold is set according to the camera being able to shoot the liquid level in the monitoring tube, calculating the adjustment amount, the adjustment amount is the difference, and adjusting the shooting position according to the adjustment amount, that is, adjusting the position of the camera, the adjustment of the shooting position of the camera is adjusted by the existing telescopic structure, such as a telescopic cylinder or other height adjustment structure. The shooting position is obtained by the existing camera, and the shooting position is adjusted by the structure of the meshing of the gear and the rack, and the shooting position is judged and then adjusted to ensure that the corresponding liquid level position image can be shot.

[0049] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A fuel tank oil level monitoring method for a combustion test, characterized in that: Includes steps: Step 1, installing the oil tank to be tested in the combustion test area, and keeping the oil inlet pipeline, oil outlet pipeline and gas outlet pipeline of the oil tank to be tested in a preset state according to the test process; The test process includes a first process and a second process, the duration of the first process is shorter than the duration of the second process, the duration of the first process is five minutes, and the duration of the second process is ten minutes; The first process is a process of maintaining a stable liquid level in the oil tank to be tested. When the test process is the first process, the oil inlet and oil outlet pipelines of the oil tank to be tested are kept in an open state, and the gas outlet pipeline is kept in a closed state. The second process is a dry burning process of the oil tank to be tested. When the test process is the second process, the oil inlet and oil outlet pipelines of the oil tank to be tested are kept in a closed state, and the gas outlet pipeline is kept in an open state. Step 2, insert a U-shaped monitoring tube into the oil tank to be tested, and keep the liquid level in the monitoring tube at the same height as the liquid level in the oil tank to be tested, so that one end of the monitoring tube extends to the inner bottom surface of the oil tank to be tested, and the other end of the monitoring tube is always located above the liquid level in the oil tank to be tested; The U-shaped monitoring tube includes a liquid level tube, an air pressure tube and an oil pipe. The liquid level tube is arranged in the vertical direction. The length of the liquid level tube is equal to the height inside the oil tank to be tested. The bottom end of the liquid level tube is flush with the inner bottom surface of the oil tank to be tested. The liquid level tube is located outside the combustion test area where the oil tank to be tested burns. One end of the air pressure tube is bonded to the top of the liquid level tube, and the other end of the air pressure tube can be extended into the oil tank to be tested and is located above the liquid level in the oil tank to be tested; the air pressure tube is connected to an oil suction device, and the air suction pipe of the air suction pump is bonded to the air pressure tube and connected to the air pressure tube, and the liquid level tube, the air pressure tube and the oil pipe form a U-shaped outer contour; One end of the oil pipe is bonded to the bottom end of the liquid level pipe, and the other end of the oil pipe can extend into the oil tank to be tested and is located within the liquid level in the oil tank to be tested, that is, the other end of the oil pipe is always located below the oil surface in the oil tank to be tested, and the distance between the ends of the air pressure pipe and the oil pipe located in the oil tank to be tested is equal to the depth in the oil tank to be tested; Step 3, photographing the liquid level position image of the monitoring tube by a camera, and displaying the page position image oil supply monitoring observation; Step 4, by installing a fiber optic sensor in the oil tank to be tested and immersing the fiber optic sensor in the oil of the oil tank to be tested, the position corresponding to the oil temperature and air temperature in the oil tank to be tested is monitored by the fiber optic sensor as the liquid level, the liquid level of the oil tank to be tested in the first process is monitored by the monitoring tube, and the liquid level of the oil tank to be tested in the second process is monitored by the fiber optic sensor.

2. The method for monitoring the fuel level in a fuel tank for a combustion test according to claim 1, characterized in that: In the step 1, the air pressure and temperature values ​​on the oil inlet pipeline, the oil outlet pipeline and the air outlet pipeline are detected respectively, and displayed during the oil quantity monitoring.

3. The method for monitoring the fuel level in a fuel tank for a combustion test according to claim 2, characterized in that: In the step 3, a liquid level position image is captured according to a preset frequency, and the liquid level height on the liquid level position image is identified and displayed.

4. The method for monitoring the fuel level in a fuel tank for a combustion test according to claim 1, characterized in that: The method further includes step 5, identifying the position information of the liquid level height on the liquid level position image, calculating the adjustment amount of the shooting position according to the difference between the position information and the initial position of the camera, and adjusting the shooting position according to the adjustment amount.

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