Pressure bearing and volume measuring method for 37m ultra-long double-cavity common-bottom structure storage tank

Abstract

The invention provides a pressure bearing and volume measuring method for a 37m ultra-long double-cavity common-bottom structure storage tank. The method comprises the following steps that S1, a common-bottom double-cavity storage tank alternate filling test is completed through a double-cavity common-bottom pressure bearing and volume measuring device; s2, the high liquid injection constant flow state is determined; s3, measuring the automatic volume of the storage tank with the double-cavity common-bottom structure; and S4, calculating the final volume of the storage tank with the double-cavity common-bottom structure. According to the pressure bearing and volume measuring method for the 37m ultra-long double-cavity common-bottom structure storage tank, accurate and automatic in-place measurement of the volumes of the ultra-long double-cavity common-bottom structure storage tank at a plurality of specified liquid levels is achieved by developing a high-precision liquid level sensor for simulating the flight working condition and a data acquisition and measurement system.

Description

Technical Field

[0001] The present invention belongs to the technical field of tank measurement, and in particular relates to a method for measuring the pressure bearing and volume of a 37m ultra-long double-chamber common-bottom structure tank. Background Technique

[0002] In order to monitor the fuel state in the tank and effectively ensure the flight process, it is necessary to measure the volume of the tank at a specific liquid level, that is, it is necessary to calibrate the overall volume of the tank and the volume values at each liquid level height through the volume of the test medium during the filling or discharging process, so as to provide necessary data support for the filling and discharging in the actual use process of the tank. The existing tanks are mainly single-chamber tanks with relatively simple structures. The existing Φ5m box hydraulic test system in the Tianjin factory area can realize the volume measurement test of single-chamber tanks with a maximum length of about 20m. The front bottom center is open for exhaust, and the tank is filled from the rear bottom. The volume measurement data of each liquid level point of the tank and the total volume of the box body are directly measured through the process liquid level sensors installed in the box, and then the volume measurement test is completed, and the state of the tank after entering the test tower.

[0003] During the filling process at the test range and the flight process of the new rocket's double-chamber common-bottom tank, a series of liquid level sensors installed inside the tank are used for multi-point measurement and real-time feedback to the control system. The existing tanks are mainly single-chamber tanks with relatively simple structures. When measuring the volume, the tank can be directly filled without involving the coordination between the upper and lower tanks for volume measurement. The existing common-bottom tank is a short-sized tank with a diameter of 3m. The volume measurement of the tank is carried out by installing process liquid level sensors on the front and rear bottom flanges and cooperating with manual control of the discharge process to measure the weight of the storage medium at each liquid level point of the tank and calculate the volume of each liquid level point. However, simply relying on the front and rear bottom flanges to provide each liquid level point for manual volume measurement cannot meet the requirements of large-diameter, large-weight, and extra-long tanks, and it does not have technological feasibility. Currently, all the tanks of the new rocket are double-chamber common-bottom structure tanks, which have the characteristics of extra-long, large thickness, and new structure. The longest tank is nearly 37m and the weight exceeds 20t. The existing Φ5m tank hydraulic test system and volume measurement method in the Tianjin factory area cannot meet the volume measurement work of the 37m extra-long double-chamber common-bottom structure tank. The existing method cannot fill and pressurize the double-chamber common-bottom tank separately, and at the same time, it cannot completely discharge the internal gas of the common-bottom tank during volume measurement to ensure the measurement accuracy. In addition, due to the too high liquid injection pressure of the extra-long tank, the flow rate is unstable, which affects the volume measurement accuracy. And because the tank volume is large, the filling and pressurization time is too long. During the formal test process, the temperature and density of the filling medium will change, and the temperature and density meters at the bottom of the tank cannot measure the medium parameters of the high liquid injection level. The actual test process continuously requires a new volume measurement method and related equipment to meet its automatic volume measurement requirements. Therefore, for the volume measurement work of the new rocket tank, it is very necessary to carry out relevant process research on the tank volume measurement technology, build a hydraulic volume test system for the 5m diameter common-bottom tank, improve the existing tank volume measurement process method, and provide more comprehensive and accurate volume measurement data for the whole rocket flight state. Summary of the Invention

[0004] In view of this, the present invention aims to propose a method for pressure bearing and volume measurement of a 37m extra-long double-chamber common-bottom structure tank to solve any of the above problems.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows: A method for pressure bearing and volume measurement of a 37m extra-long double-chamber common-bottom structure tank includes the following steps: S1. Complete the alternate filling test of the common-bottom double-chamber tank through the double-chamber common-bottom pressure bearing and volume measurement device; S2. Determine the constant and stable flow state of high liquid injection; S3. Measure the automatic volume of the double-chamber common-bottom structure tank; S4. Calculate the final volume of the double-chamber common-bottom structure tank.

[0006] Further, the double-chamber common-bottom pressure-bearing and volume measuring device includes a storage tank, a first emergency discharge device and a first air supply and exhaust device installed above the storage tank. The storage tank has a double-chamber common-bottom structure and includes an upper chamber box body and a lower chamber box body. The upper chamber box body is connected to the lower bottom of the storage tank through an upper conveying pipe to form an upper tank filling port; the lower chamber box body is connected to the lower bottom of the storage tank through a lower conveying pipe to form a lower tank filling port; an emergency discharge device and an air supply and exhaust device are installed on the upper bottom of the upper chamber box body, and a liquid level leveling device, a second emergency discharge device and a second air supply and exhaust device are added at the flange of the side wall of the lower chamber box body to discharge the excess gas inside the lower chamber box body.

[0007] Further, the specific method for determining the high-liquid-injection constant and stable flow state in S2 is as follows: S21. Build a simple test device using the storage tank test system. The simple test device is to add a pressure sensor, a control valve, and a detection flowmeter between the flowmeter and the process storage tank in the storage tank test system. S22. During the process of the liquid injection rising, there is a change in the pressure difference between the liquid injection pressure and the hydraulic pump pressure, and the adjustment method of the hydraulic pump under the state of the liquid injection pressure value change is obtained. S23. Calculate the specific filling volume through the flow rate and time.

[0008] Further, the method for measuring the automatic volume of the double-chamber common-bottom structure storage tank in S3 is as follows: S31. The double-chamber common-bottom storage tank volume test injects water into the upper chamber box body and the lower chamber box body in two paths, and the two paths operate independently. If there is internal leakage during the flow rate filling, the volume measurement stops. The filling flow rate points can be set, and the filling process is: determination of filling zero point → small-flow water injection → large-flow water injection → stop water injection → make-up water. S32. Before calibrating the storage tank volume, first confirm the zero point. Use the small-flow path to fill water by gravity to the zero point, and close the valve when reaching the zero point position. S33. After the zero position is confirmed, the flow rate points of the two paths are in a stable flow state. First, carry out small-flow path water injection, and at the same time, the large-flow path is in a circulating stable flow state, and the flowmeter volume value is fed back through the sensor. S34. When the water submerges the sensor, stop the small-flow path water injection and switch to the large-flow path water injection. During the water injection process, when the liquid level rises to the point-type liquid level gauge or continuous liquid level gauge in the storage tank, the corresponding sensor feeds back to the PLC to record the volume value of the flowmeter at the current position until the water is injected to the front bottom side of the storage tank. S35. After the large-flow water injection reaches the front bottom side of the storage tank, trigger the lower end of the liquid level sensor at the front bottom side of the storage tank, stop the large-flow path water injection, and switch to the small-flow path water injection. When the upper end total volume point of the liquid level sensor is triggered, the PLC records the total volume value of the flowmeter, and at the same time stops the small-flow path water injection. S36. Carry out make-up water to the storage tank until the water is full and stop the make-up water, and record the cumulative make-up water volume.

[0009] Further, the method for calculating the final volume of the double-chamber common-bottom structure storage tank in S4 is as follows: S41. Use a common storage tank with the same diameter, control the variables to only the experiment time and filling height, and complete the final volume calculation through finite element analysis; S42. Analyze the heat exchange situation between the test medium in the tank and the ambient temperature under different temperature differences through the finite element thermodynamics analysis method, and obtain the influence of the filling time and liquid filling height on the temperature change of the medium; S43. Judge whether the temperature change of the test medium during the filling process of the ultra-long storage tank meets the measurement requirements. If the temperature change is large, resulting in a large error in the measurement value of the densitometer, it is necessary to control the temperature of the test medium in the storage tank.

[0010] S44. Analyze the change law of the influence of the two parameters of temperature and density on the final volume relative to the theoretical values during the filling process, and calculate the final volume according to this during the formal test process.

[0011] Compared with the prior art, the pressure-bearing and volume measurement method of the 37m ultra-long double-chamber common-bottom structure storage tank of the present invention has the following advantages: (1) The pressure-bearing and volume measurement method of the 37m ultra-long double-chamber common-bottom structure storage tank of the present invention realizes the accurate and automatic in-situ measurement of the volume at multiple specified liquid levels of the ultra-long double-chamber common-bottom structure storage tank by developing a high-precision liquid level sensor and a data acquisition and measurement system that simulate the flight conditions. This device realizes the volume measurement test of the ultra-long double-chamber common-bottom structure storage tank from scratch, provides reliable data support for the fuel leakage and engine shutdown timing during the target range filling and the whole rocket flight process, and is of great significance for improving fuel utilization rate, increasing effective transportation load and ensuring flight safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is the flow chart of the pressure-bearing and volume measurement method of the 37m ultra-long double-chamber common-bottom structure storage tank described in the embodiment of the present invention; Figure 2 is the storage tank structure in the prior art; Figure 3 is the schematic diagram of the double-chamber common-bottom pressure-bearing and volume measurement device described in the embodiment of the present invention Figure 1 ; Figure 4 is the schematic diagram of the double-chamber common-bottom pressure-bearing and volume measurement device described in the embodiment of the present invention Figure 2 ; Figure 5Schematic diagram of the dual-chamber common-bottom pressure-bearing and volume measurement device described in the embodiments of the present invention Figure 3 ; Figure 6 Schematic diagram of a simple test device for the tank test system described in the embodiments of the present invention; Figure 7 Data analysis for calculating the final volume of the dual-chamber common-bottom structure tank described in the embodiments of the present invention Figure 1 ; Figure 8 Data analysis for calculating the final volume of the dual-chamber common-bottom structure tank described in the embodiments of the present invention Figure 2 。

[0013] Explanation of reference numerals: 1 - Tank; 11 - Upper chamber box body; 12 - Lower chamber box body; 13 - Delivery pipe; 14 - Upper tank filling port; 15 - Lower tank filling port; 2 - Liquid level leveling device; 3 - First emergency discharge device; 4 - First air discharge and replenishment device; 5 - Second emergency discharge device; 6 - Second air discharge and replenishment device. Detailed implementation manners

[0014] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0015] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0016] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0017] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0018] Currently, the volume of the storage tank is mainly obtained by measuring the weight of the test medium (currently mainly deionized water medium) at each liquid level and converting it into the volume of the test medium through the actual density of the test medium. Therefore, it is necessary to ensure the accuracy of the weight of the test medium and the accuracy of the density of the test medium. Since the compressibility of water is relatively low, with a deviation of about one ten-thousandth in the pressure range of 0.1 MPa to 0.3 MPa, the density is mainly affected by temperature.

[0019] A method for measuring the pressure bearing and volume of a 37m ultra-long double-chamber common-bottom structure storage tank, as Figure 1 、 Figures 3 to 8 shown, includes the following steps: S1. Add a double-chamber common-bottom pressure bearing and volume measurement device to complete the alternate filling test of the common-bottom double-chamber storage tank; Existing experimental towers are used for volume measurement and pressure bearing tests on single-chamber storage tanks. For common-bottom storage tanks, it is necessary to conduct filling and pressure bearing tests on the upper chamber box body and the lower chamber box body respectively. At the same time, to ensure the accuracy of volume measurement and avoid the influence of residual gas on the measured volume value, a double-chamber volume measurement of the double-chamber common-bottom structure storage tank is set up.

[0020] The double-chamber common-bottom pressure bearing and volume measurement device includes a storage tank 1 and a first emergency discharge device 3 and a first air discharge and compensation device 4 installed above it. The storage tank 1 has a double-chamber common-bottom structure. For a double-chamber common-bottom structure storage tank, it is necessary to measure the volume of the upper and lower chamber box bodies simultaneously. The storage tank 1 includes an upper chamber box body 11 and a lower chamber box body 12. The upper chamber box body 11 is connected to the lower bottom of the storage tank 1 through an upper conveying pipe 13 to form an upper tank filling port 14; the lower chamber box body 12 is connected to the lower bottom of the storage tank 1 through a lower conveying pipe to form a lower tank filling port 15. The set double-pipeline system is used to fill and pressurize the upper and lower chamber box bodies respectively.

[0021] An emergency discharge device 3 and an air discharge and compensation device 4 are installed on the upper bottom of the upper chamber box body 11. The upper chamber box body 11 is kept in communication with the atmosphere through the emergency discharge device 3 and the volume filling is verified, which can ensure that all the excess gas in the upper chamber box body is discharged when the liquid level rises during filling from below, and ensure the accuracy of volume measurement. The first emergency discharge device 3 and the first air discharge and compensation device 4 are both existing equipment.

[0022] For the lower chamber box body 12 of the double-chamber common-bottom structure storage tank 1, due to the existence of the common-bottom structure, when the liquid level rises during bottom-up filling, it is impossible to verify that the volume is full and remove excess gas at the uppermost end of the lower chamber box body 12. The side wall of the lower chamber box body 12 is connected with a liquid level leveling device 2, a second emergency discharge device 5, and a second air supply and discharge device 6. A liquid level leveling device 2 and a second emergency discharge device 5 are added at the flange of the side wall of the lower chamber box body 12 to make the height of the position where the lower chamber box body 12 communicates with the atmosphere flush with the uppermost end of the lower chamber box body 12, so as to be able to verify that the volume is full. There is an included angle area A formed between the distance from the flange of the side wall of the lower chamber box body 12 to the uppermost end of the lower chamber box body and the common bottom. The residual gas in the included angle area cannot be removed through the liquid level leveling device 2. A second air supply and discharge device 6 is added at the side wall flange to make the uppermost end of the included angle area communicate with the atmosphere through the second air supply and discharge device 6, so as to be able to discharge the excess gas inside the lower chamber box body 12 and ensure the accuracy of volume measurement. The liquid level leveling device, the second emergency discharge device, and the second air supply and discharge device are all prior arts and will not be elaborated here.

[0023] S2. Determine the constant and stable flow state of high liquid injection; The height of the box body is 37m, and the height is relatively high, so the liquid injection pressure is also relatively high. During the filling process of the upper chamber box body, it is filled through the connection between the filling pipe and the conveying pipe flange. At this time, the pressure difference between the pressure of the hydraulic pump of the filling pipe and the filling flange of the conveying pipe will change with the rise of the liquid injection, making the flow rate unstable during the filling process. When calculating the volume through the flow rate, it will lead to poor measurement accuracy. A feedback adjustment system is added to ensure the stability of the flow rate during the filling process, and thus ensure the accuracy of volume measurement.

[0024] S21. Use the storage tank test system to build a simple test device. Add a pressure sensor, a control valve, and a detection flowmeter between the flowmeter and the process storage tank in the storage tank test system; control the opening degree through the control valve to approximately simulate the change in the pressure difference brought by the liquid columns before and after the filling pump, detect the actual pressure through the pressure sensor to approximately verify the change in pressure, and determine whether the flow rate remains stable by detecting the flow rate indication of the flowmeter or the indication of the system free flowmeter.

[0025] S22. During the process of the liquid injection rising, there is a change in the pressure difference between the liquid injection pressure and the hydraulic pump pressure. The specific corresponding matching relationship between the filling capacity parameters of the hydraulic pump and the pressure difference needs to be measured through the experimental device. Add a control valve and a detection flowmeter between the original hydraulic pump, flowmeter and the filling flange of the storage tank conveying pipe. Control the opening degree through the control valve to approximately simulate the change in the pressure difference brought by the liquid columns before and after the filling pump, detect the actual pressure through the pressure sensor to approximately verify the change in pressure, and determine whether the final flow rate entering the storage tank remains stable by detecting the display value of the flowmeter, so as to obtain the adjustment method of the hydraulic pump under the state of changing liquid injection pressure values.

[0026] After obtaining the matching relationship between the pressurizing capacity of the hydraulic pump, the liquid column height, and the pressure difference between hydraulic pumps, the system program can be set accordingly. During the actual measurement of the volume, by monitoring the change in the pressure difference between the hydraulic pump pressure and the liquid column pressure during the filling process, the filling capacity of the hydraulic pump can be feedback-controlled to offset the pressure difference change caused by the liquid column pressure, ensuring that the filling flow rate remains stable during the rise of the liquid column. Finally, the specific filling volume can be calculated through the flow rate and time.

[0027] In addition, the change in the mass of the test medium is measured by an electronic scale installed below the process storage tank. By comparing the weight results detected by the flowmeter method, the consistency of the mass results is verified under non-constant flow filling conditions. According to the experimental results, the control range of the pressure difference before and after the filling pump during high liquid column filling is determined. When this range is exceeded, the filling capacity of the filling pump should be increased, such as adding an additional filling pump pipeline and changing the flow control value to improve stability.

[0028] S3. Measure the automatic volume of the double-chamber common-bottom structure storage tank; Currently, the main methods for measuring the volume of storage tanks are the flowmeter method and the weighing method.

[0029] The basic principle of the weighing method is as follows: The solution in the storage tank is drained through the drain-back pipeline to a specified liquid level, and an electronic scale measures the mass of the solution inside the storage tank. Then, combined with the density of the solution, the volume of the storage tank at this liquid level is calculated. The existing storage tank volume measurement system in the Tianjin plant area uses the flowmeter method. Its basic principle is to use a flowmeter to obtain the mass of pure water filled into the storage tank, and then combined with the density, calculate the volume of the filled liquid, that is, the liquid level volume of the storage tank. The core components of the flowmeter method are the mass flowmeter, variable-frequency pump, and process liquid level sensor. The liquid level information inside the storage tank is collected by a liquid level sensor installed inside it, and the pressure information is collected by pressure sensors installed on the storage tank and in the filling pipeline. This method can conveniently obtain the volume of each liquid level point inside the storage tank. For the common-bottom storage tank, it mainly includes the measurement of the volumes of different liquid level points inside the upper and lower tanks. This can be achieved by separately filling the upper and lower tanks of the storage tank. To ensure the structural stiffness of the product, as needed, a certain pressure is added to the lower tank before filling the upper tank of the storage tank. Therefore, it is necessary to efficiently switch between the storage tank pressurization and filling subsystems and maintain the stability of the flowmeter results.

[0030] The specific method for filling and automatically measuring the volume of the upper and lower cavity boxes is as follows: S31. During the double-chamber common-bottom storage tank volume test, water is injected into the upper and lower cavity boxes in two independent paths. During the injection process, the two paths can be switched according to the injection stage. If there is internal leakage during the flow rate filling, the volume measurement stops, and the set flow rate points can be adjusted. The filling process is as follows: Determine the filling zero point → Inject water at a small flow rate → Inject water at a large flow rate → Stop injecting water → Refill water; S32. Before calibrating the volume of the storage tank, first confirm the zero point. Fill the pipeline with water to the zero point position to ensure that the starting point of each water filling is the same. Use the gravity filling of the small flow path to reach the zero point. At the same time, adjust the opening of the regulating valve to 10% or less to ensure that the liquid level rises slowly and the zero point position is accurate. Close the valve when reaching the zero point position.

[0031] S33. After zero point confirmation, stabilize the flow at two flow points. First, fill the small flow path with water, while the large flow path is in a circulating and stable flow state. There is a depletion shutdown sensor at the bottom of the storage tank. The small fluctuation of the small flow water filling helps the sensor measure accurately. The depletion shutdown sensor feeds back to the PLC to record the volume value of the flowmeter at the current position.

[0032] S34. After the water covers the depletion shutdown sensor, stop filling the small flow path and switch to filling the large flow path. During the water filling process, when the liquid level rises to the point-type liquid level gauge or continuous liquid level gauge in the storage tank, the corresponding sensor feeds back to the PLC to record the volume value of the flowmeter at the current position until the water is filled to the front bottom side of the storage tank.

[0033] S35. After filling the large flow path to the front bottom side of the storage tank, trigger the lower end of the liquid level sensor at the front bottom side of the storage tank, stop filling the large flow path, and switch to filling the small flow path. When triggering the total volume point at the upper end of the liquid level sensor, the PLC records the total volume value of the flowmeter, and at the same time, stop filling the small flow path.

[0034] S36. The water replenishment path replenishes water. The water replenishment pipeline is connected to the reserved interface of the water replenishment path corresponding to the front bottom of the storage tank on the tower platform. First, exhaust the water replenishment pipeline. During the exhaust process, align the outlet of the water replenishment gun with the drainage pipeline on the tower until the outlet of the water replenishment gun has a continuous columnar water flow and then stop. Zero the electronic flow meter on the water replenishment gun, align it with the manhole at the front bottom of the storage tank, and pull the trigger of the water replenishment gun to replenish water until the water is full and stop replenishing water, and record the cumulative water replenishment amount on the electronic flow meter.

[0035] S4. Calculate the final volume of the storage tank with a double-chamber common bottom structure.

[0036] The temperature and density of the hydraulic test medium will change greatly during the experiment, causing changes in the volume measurement value. Since the filling time of the storage tank is long and there are many coupling surfaces between the temperature field of the storage tank and the ambient temperature field at this diameter, during the actual filling process of the storage tank, the temperature of the test medium exchanges with the ambient temperature, resulting in a large temperature change. The large temperature change causes errors in the density meter. When calculating the final volume, it is impossible to measure the density values at each point of the storage tank. Obtain the density parameter through a point near the filling port. It is necessary to study the influence of temperature and density on the long-term hydraulic experiment, analyze the influence of the two factors on the volume value and the influence law, and obtain the calculation method of the final volume.

[0037] S41. Use ordinary storage tanks with the same diameter, control the variables to only the experimental time and filling height, simulate the influence of height and filling time on the temperature and density of the filling medium through finite element analysis, and verify the accuracy of the finite element analysis through experiments. Use this as basic data to provide a relatively accurate parameter basis for the ultra-high region that cannot be verified through experiments. Analyze the specific temperature and density changes in the ultra-high region through finite element analysis, obtain the change trends of temperature and density between different height regions and the differences between different heights and the bottom region of the storage tank that can be measured by the density meter. Finally, analyze the average density and temperature of the entire tank through the measured values of the density meter and thermometer to complete the final volume calculation.

[0038] S42. Analyze the heat exchange situation between the test medium in the tank and the ambient temperature under different temperature differences through the finite element thermodynamics analysis method, calculate the change in the temperature of the test medium during the filling time, and analyze the temperature change of an ordinary storage tank with the same diameter as the ultra-long storage tank under different liquid filling heights through finite element analysis. Verify the rationality of the numerical simulation analysis results through experiments. Install temperature sensors on the inner wall of the process storage tank with the same diameter at certain intervals to measure the temperature change of the test medium during the filling process of the storage tank, and obtain the influence of filling time and liquid filling height on the temperature change of the medium.

[0039] S43. According to the simulation analysis results and experimental analysis results, combined with the analysis of the influence of the change in the medium temperature on the density change, judge whether the temperature change of the test medium during the filling process of the ultra-long storage tank meets the measurement requirements. If the temperature change is large, resulting in a large error in the measured value of the density meter, it is necessary to control the temperature of the test medium in the storage tank.

[0040] S44. Analyze the change law of the final influence of the two parameters of temperature and density on the volume relative to the theoretical value during the filling process, and calculate the final volume according to this during the formal test process.

[0041] The method for measuring the pressure bearing and volume of the 37m ultra-long double-chamber common-bottom structure storage tank of this application realizes the accurate automatic in-situ measurement of the volume at multiple specified liquid levels of the ultra-long double-chamber common-bottom structure storage tank by developing a high-precision liquid level sensor and a data acquisition and measurement system that simulate flight conditions. This device has achieved the transformation from scratch in the volume measurement test of the ultra-long double-chamber common-bottom structure storage tank, providing reliable data support for fuel leakage and engine shutdown timing during the filling at the firing range and the entire rocket flight process, and is of great significance for improving fuel utilization rate, increasing effective transport payload, and ensuring flight safety.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for measuring the pressure and volume of a 37m ultra-long double-cavity common bottom tank, characterized in that: The steps include: S1. Complete the alternating filling test of the double-chamber tank with common bottom by using the double-chamber common bottom pressure bearing and volume measuring device; S2, determine the constant flow state of high liquid injection; S3. Measure the automated volume of the double-cavity common-bottom structure tank; S4. Calculate the final volume of the double-cavity common-bottom structure tank.

2. The method for measuring the pressure and volume of a 37m ultra-long double-cavity common bottom tank according to claim 1 is characterized by: The double-chamber common-bottom pressure-bearing and volume measuring device includes a storage tank and a No. 1 emergency discharge device and a No. 1 exhaust and air-supplementing device installed above the storage tank. The storage tank is a double-chamber common-bottom structure, and the storage tank includes an upper chamber box body and a lower chamber box body. The upper chamber box body is connected to the lower bottom of the storage tank through an upper delivery pipe to form an upper tank filling port; the lower chamber box body is connected to the lower bottom of the storage tank through a lower delivery pipe to form a lower tank filling port; an emergency discharge device and an exhaust and air-supplementing device are installed on the upper bottom of the upper chamber box body, and a liquid level leveling device, a No. 2 emergency discharge device and a No. 2 exhaust and air-supplementing device are added to the side wall flange of the lower chamber box body to discharge excess gas inside the lower chamber box body.

3. The method for measuring the pressure and volume of a 37m ultra-long double-cavity common bottom tank according to claim 1 is characterized by: The specific method for determining the constant flow state of high liquid injection in S2 is: S21. Use the tank test system to build a simple test device. The simple test device is to add a pressure sensor, a control valve, and a detection flow meter between the flow meter and the process tank in the tank test system; S22, during the process of liquid injection increasing, the pressure difference between the liquid injection pressure and the hydraulic pump changes, and the adjustment method of the hydraulic pump under the state of liquid injection pressure value changing is obtained; S23. Calculate the specific filling volume based on flow rate and time.

4. The method for measuring the pressure and volume of a 37m ultra-long double-cavity common bottom tank according to claim 1 is characterized by: The method for measuring the automated volume of the double-cavity common-bottom structure tank in S3 is: S31. Double-chamber common bottom tank capacity test: two ways are used to fill water into the upper chamber and the lower chamber. The two ways are operated independently. If there is leakage, the flow filling will stop. The filling flow point can be set. The filling process is: filling zero point determination → small flow water filling → large flow water filling → stop water filling → replenish water; S32. Before calibrating the tank volume, confirm the zero point first, use a small flow rate to gravity fill water to the zero point, and close the valve when it reaches the zero point; S33, after the zero position is confirmed, the two flow points are stable, the small flow path is filled with water first, and the large flow path is in a circulating stable flow state, and the flow meter volume value is fed back through the sensor; S34, when the water has submerged the sensor, stop filling water from the small flow path and switch to filling water from the large flow path. During the filling process, when the liquid level rises to the point level gauge or continuous level gauge in the tank, the corresponding sensor feeds back to the PLC to record the current position flow meter volume value until the water is filled to the front bottom side of the tank; S35, after the large flow of water is injected to the front bottom side of the tank, the lower end of the liquid level sensor at the front bottom side of the tank is triggered, the large flow water injection is stopped, and the small flow water injection is switched. When the total volume point at the upper end of the liquid level sensor is triggered, the PLC records the total volume value of the flow meter and stops the small flow water injection at the same time; S36, replenish water to the storage tank until it is full, and stop replenishing water, and record the cumulative amount of water replenished.

5. The method for measuring the pressure and volume of a 37m ultra-long double-cavity common bottom tank according to claim 1 is characterized by: The method for calculating the final volume of the double-chamber common-bottom structure tank in S4 is: S41. Use a common tank with the same diameter, control the variables to only the experimental time and filling height, and complete the final volume calculation through finite element analysis; S42. Analyze the heat exchange between the test medium in the box and the ambient temperature under different temperature differences by using the finite element thermodynamic analysis method, and obtain the influence of the filling time and liquid injection height on the temperature change of the medium; S43. Determine whether the temperature change of the test medium during the filling process of the super-long tank meets the measurement requirements. If the temperature change is large, resulting in a large error in the density meter measurement value, the temperature of the test medium in the tank needs to be controlled; S44. Analyze the changing patterns of the temperature and density parameters relative to the theoretical values ​​on the final volume during the filling process, and calculate the final volume based on this during the formal test.

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