A liquid oxygen storage tank exhaust system and method for rocket bodies

Abstract

This invention provides a venting system and method for a liquid oxygen storage tank in a rocket body. The venting system includes: a low-temperature, high-flow-rate venting pipe, with its head connected to the top of the liquid oxygen storage tank, suitable for venting large-flow, low-temperature oxygen; a safety function venting pipe, with its head connected to the top of the liquid oxygen storage tank and connected in parallel with the low-temperature, high-flow-rate venting pipe, suitable for venting high-temperature oxygen; the flow rate of the safety function venting pipe meets the emergency venting flow rate required by the liquid oxygen storage tank during the rocket ignition stage when the pressure overshoots; an oxygen tank pressure sensor, installed at the top of the liquid oxygen storage tank; and a control system, communicatively connected to the oxygen tank pressure sensor and the safety function valve. This venting system can respond to different venting needs of the rocket body's liquid oxygen storage tank at different stages, meeting both the large-flow, low-temperature oxygen vapor venting needs during the high-flow-rate filling stage and the emergency high-temperature oxygen venting needs during the power system testing stage.

Description

Technical Field

[0001] This invention relates to the field of ground propulsion system testing technology for rocket core stage modules, specifically to an exhaust system and method for a liquid oxygen storage tank in a rocket body. Background Technology

[0002] Liquid oxygen is a commonly used propellant medium in launch vehicles. As launch vehicle thrust continues to increase, the demand for liquid oxygen is also growing, thus raising the requirements for venting liquid oxygen tanks. To meet the testing needs of the rocket's liquid oxygen tank propulsion system, a corresponding venting device needs to be installed on the ground system. The ground venting system needs to accommodate the large amounts of cryogenic oxygen vapor emitted during the fueling phase, as well as the need to urgently release high-temperature gases due to pressure overshoot during operation. The temperature, pressure, and flow rate of the venting vary at different stages, especially during pressure overshoot in testing, requiring a fast venting response to avoid damage from overpressure in the rocket's liquid oxygen tank. However, existing liquid oxygen tank venting systems only have a single venting pipeline, making it difficult to adapt to different operating conditions. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to respond to the different exhaust requirements of the liquid oxygen storage tank of the rocket body at different stages, so as to meet the exhaust requirements of a large amount of low temperature oxygen vapor during the high flow refueling stage, and at the same time meet the emergency exhaust requirements of high temperature oxygen during the power system test stage.

[0004] To solve the above-mentioned technical problems, this application provides a liquid oxygen storage tank exhaust system for rocket bodies, comprising:

[0005] A low-temperature, high-flow-rate exhaust pipeline is connected at its head end to the top of a liquid oxygen storage tank, suitable for exhausting high-flow-rate low-temperature oxygen; the low-temperature, high-flow-rate exhaust pipeline includes a first thermal insulation buffer and an exhaust valve connected in sequence; the exhaust valve is a low-temperature oxygen valve; the first thermal insulation buffer is a cylindrical container with an insulated outer wall, and the inner diameter of the first thermal insulation buffer is larger than the inner diameter of the pipeline required for the maximum flow rate of exhaust during the filling stage.

[0006] The safety function exhaust pipe is connected at its head to the top of the liquid oxygen storage tank and is connected in parallel with the cryogenic high-flow exhaust pipe. The flow rate of the safety function exhaust pipe meets the emergency exhaust flow rate required by the liquid oxygen storage tank during the rocket ignition stage when the pressure is over-adjusted. The safety function exhaust pipe includes a second thermal insulation buffer and a safety function valve connected in sequence. The safety function valve is a pneumatically controlled valve. The second thermal insulation buffer is a cylindrical container, and the inner diameter of the second thermal insulation buffer is larger than the inner diameter of the pipe required for the emergency exhaust flow rate.

[0007] The oxygen tank pressure sensor is located on top of the liquid oxygen storage tank;

[0008] The control system communicates with the oxygen tank pressure sensor and safety valve.

[0009] Furthermore, the low-temperature, high-flow-rate exhaust pipeline also includes an exhaust balancer; the exhaust balancer is located downstream of the exhaust valve and is connected to the outside.

[0010] Furthermore, both the safety valve and the exhaust valve are pneumatic control valves with a closing action chamber and an opening action chamber.

[0011] The closing chamber is supplied with air by a normally open two-position three-way solenoid valve, and the opening chamber is supplied with air by a normally closed two-position three-way solenoid valve.

[0012] Furthermore, the control air for closing the exhaust valve is supplied by the first normally open two-position three-way solenoid valve, and the control air for opening the exhaust valve is supplied by the first normally closed two-position three-way solenoid valve.

[0013] Furthermore, the closing control air of the safety function valve is supplied by the second normally open two-position three-way solenoid valve, and the opening control air of the safety function valve is supplied by the second normally closed two-position three-way solenoid valve.

[0014] Furthermore, each normally open 2-position 3-way solenoid valve and normally closed 2-position 3-way solenoid valve is communicatively connected to the control system; the control system simultaneously sends action signals to the normally open and normally closed 2-position 3-way solenoid valves belonging to the same pneumatic control valve, thereby opening the corresponding pneumatic control valve; the control system simultaneously disconnects the action signals to the normally open and normally closed 2-position 3-way solenoid valves belonging to the same pneumatic control valve, thereby closing the corresponding pneumatic control valve.

[0015] Furthermore, the low-temperature high-flow exhaust pipe and the safety function exhaust pipe are connected to the same interface located on the top of the liquid oxygen storage tank via a tee.

[0016] A method for venting a liquid oxygen storage tank in a rocket body, using the aforementioned liquid oxygen storage tank venting system, involves determining the venting requirements and venting medium parameters at different venting stages, and selecting a cryogenic, high-flow-rate venting pipeline and a safety-function venting pipeline of appropriate specifications. The working steps of the safety-function venting pipeline are as follows:

[0017] S01: Set the pressure range (P1, P2) of the liquid oxygen storage tank;

[0018] S02: Collect the air cushion pressure Pt inside the top of the liquid oxygen storage tank;

[0019] S03: When Pt≥P2, open the safety valve to release air;

[0020] S04: Continue venting until Pt = P1, then close the safety valve.

[0021] Further, step S01 includes the following steps:

[0022] a. Based on the liquid oxygen tank pressure required for stable operation of the rocket engine, set the ideal values ​​for the pressure range (P1', P2');

[0023] b. The sum of the pressure signal transmission time, the control system electrical signal response transmission time, the solenoid valve action time, and the control gas filling time of the valve action chamber is set as the inherent response time Δt;

[0024] c. Determine the pressure change value of the liquid oxygen tank within the time interval Δt; the pressure change value of the liquid oxygen tank during the opening of the safety valve is δP; the pressure change value of the liquid oxygen tank during the closing of the safety valve is δP'.

[0025] d. Set the final pressure range (P1, P2), P1 = P1' - δP, P2 = P2' + δP'.

[0026] Further, step c includes:

[0027] 1) The test setting for the safety function valve is to open the pressure value as P3 and close the pressure value as P3'.

[0028] 2) The pressure in the liquid oxygen storage tank is increased at a certain pressurization rate v. When it reaches P3, the safety valve starts to open. After the inherent reaction time Δt, the liquid oxygen storage tank pressure value when the safety valve is actually opened is measured to be P4. The pressurization pressure overshoot δP = P4 - P3 is obtained.

[0029] 3) The pressure in the liquid oxygen storage tank is reduced at a certain exhaust rate v'. When it reaches P3', the safety valve starts to close. After the inherent reaction time Δt, the liquid oxygen storage tank pressure when the safety valve is actually closed is measured to be P4'. The exhaust pressure overshoot δP' = P4' - P3' is obtained.

[0030] 4) Test the actual opening pressure value P4 and actual closing pressure value P4' corresponding to n different boost rates v and exhaust rates v'. Then, the pressure overshoot δP and δP' corresponding to n groups can be obtained under different boost rates v and exhaust rates v' within Δt time.

[0031] 5) The control system calculates the pressurization rate v or exhaust rate v' of the liquid oxygen storage tank in real time based on the data from the oxygen tank pressure sensor, and directly uses the corresponding δP or δP' obtained from step 4 or calculated by the difference method based on the calculated current pressurization rate v or exhaust rate v'.

[0032] By adopting the above technical solution, the present invention has the following technical effects:

[0033] The rocket body liquid oxygen storage tank exhaust system provided by this invention, by setting up a low-temperature high-flow exhaust pipeline, a safety function exhaust pipeline, an oxygen tank pressure sensor and a control system, enables the low-temperature high-flow exhaust pipeline to be suitable for rapid depressurization of the storage tank, and the safety function exhaust pipeline can be used as a safety valve device; thereby avoiding the adverse effects of alternating low-temperature oxygen and high-temperature oxygen exhaust on equipment characteristics, solving the response time requirements of exhaust at each stage, and avoiding the risk of overpressure in the rocket body liquid oxygen storage tank. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0036] Figure 2 This is a schematic diagram of the theoretical calculation steps for setting the pressure range of the liquid oxygen storage tank in Embodiment 2 of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1-Nitrogen cylinder; 2-Filter; 3-Gas source shut-off valve; 4-Pressure regulator; 5-Pressure gauge; 6-Gas supply pipeline; 7-Closed-loop control computer; 8-Solenoid valve control signal line; 9-First normally open 2-position 3-way solenoid valve; 10-First normally closed 2-position 3-way solenoid valve; 11-Second normally open 2-position 3-way solenoid valve; 12-Second normally closed 2-position 3-way solenoid valve; 13-Closing chamber; 14-Opening chamber; 15-Valve position signal line; 16-Exhaust valve; 17-Safety valve; 18-Reducing connector; 19-Oxygen tank pressure sensor; 20-Liquid oxygen storage tank; 21-Relay combination; 22-PLC slave station; 23-PLC master station; 24-Emergency control console; 25-Optical terminal switch; 26-First thermal insulation buffer; 27-Second thermal insulation buffer; 28-Emission balancer. Detailed Implementation

[0039] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0040] It should be noted in the description of this invention that the coordinate system used in describing the orientation is determined by the orientation of the corresponding component's main view, and the naming of the observation angle of the corresponding view is also based on this. Therefore, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] 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. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] Example 1

[0044] This embodiment provides an exhaust system for a liquid oxygen storage tank in a rocket body.

[0045] In one implementation, such as Figure 1 As shown, it includes: a low-temperature, high-flow exhaust pipe, a safety function exhaust pipe, an oxygen tank pressure sensor 19, and a control system.

[0046] The cryogenic high-flow-rate exhaust pipeline is connected to the top of the liquid oxygen storage tank 20. It is suitable for exhausting large-flow-rate cryogenic oxygen and is also typically used to release excess oxygen produced by endothermic evaporation during the rocket's static phase. The cryogenic high-flow-rate exhaust pipeline includes a first thermally insulated buffer 26 and an exhaust valve 16 connected sequentially. The exhaust valve 16 is a cryogenic oxygen valve. The first thermally insulated buffer 26 is a cylindrical container, and its inner diameter is larger than the pipe inner diameter required for the maximum exhaust flow rate during the refueling phase.

[0047] The first end of the safety function exhaust pipe is also connected to the top of the liquid oxygen storage tank 20 and is connected in parallel with the cryogenic high-flow exhaust pipe. The flow rate of the safety function exhaust pipe meets the emergency exhaust flow rate required by the liquid oxygen storage tank 20 during the rocket ignition stage when the pressure is over-adjusted, and is suitable for high-temperature oxygen exhaust. The pipe can be connected using a reducing coupling 18 when encountering components of different specifications. The safety function exhaust pipe includes a second thermal insulation buffer 27 and a safety function valve 17 connected in sequence. The safety function valve 17 is a high-temperature oxygen type pneumatic control valve. The structure of the second thermal insulation buffer 27 is similar to that of the first thermal insulation buffer 26, but its inner diameter is larger than the inner diameter of the pipe required for the emergency exhaust flow rate.

[0048] The oxygen tank pressure sensor 19 is located on top of the liquid oxygen storage tank 20.

[0049] The control system is communicatively connected to the oxygen tank pressure sensor 19 and the safety valve 17, thereby forming a closed-loop control circuit for adjusting the internal pressure of the liquid oxygen storage tank 20.

[0050] The safety venting line of this device serves as a safety device for the internal pressure of the liquid oxygen storage tank 20. Different sizes of safety valves 17 can be used to meet varying venting flow requirements. The safety valve 17 employs a pneumatic valve and is remotely controlled for opening and closing, rather than a conventional mechanical safety valve. This avoids the uncontrollable factors inherent in conventional mechanical safety valves, which rely solely on their mechanical structure to sense tank pressure. For example, in alternating hot and cold working environments, temperature differences can change the size and properties of the pressure-sensing components, leading to variations in the response pressure and speed of the safety venting action, and potentially even mechanical failure. Furthermore, pneumatic valves suitable for high-temperature oxygen are more readily available on the market and offer more reliable performance.

[0051] Furthermore, the operation of the exhaust port and its connecting pipelines of the rocket body liquid oxygen storage tank 20 is often intermittent, and the flow rate or medium state within the pipelines is dynamically adjusted. Therefore, the pipelines may sometimes be filled with large amounts of low-temperature oxygen vapor, and at other times with high-temperature oxygen at a certain pressure. Consequently, the pipelines and related components face alternating high and low temperature operating conditions, and improper handling may lead to valve malfunctions, tank overpressure, and other accidents. Therefore, the exhaust device connected to the exhaust port of the rocket body liquid oxygen storage tank 20 is divided into two parts: a low-temperature, high-flow exhaust pipeline and a safety function exhaust pipeline. The rocket body liquid oxygen storage tank 20 is connected to the low-temperature, high-flow exhaust pipeline and the safety function exhaust pipeline respectively via a tee. A first thermal insulation buffer 26 and a second thermal insulation buffer 27 are respectively installed at the front end of the valve equipment of the two exhaust pipelines to isolate the impact of the exhaust medium from the rocket body liquid oxygen storage tank 20 on the downstream of the thermal insulation buffer. Specifically, because the thermal insulation buffer has a certain cavity, it can form a pressure buffer zone, thereby preventing heat exchange between the inlet and outlet gases of the buffer during the static stage. The inlet and outlet of the thermal insulation buffer are separated by a certain path length, thus isolating the low / high temperature pipes before and after the thermal insulation buffer and preventing heat conduction through the pipe wall. Therefore, the installation of the thermal insulation buffer can avoid the temperature impact on the downstream of the pipe caused by pipe heat conduction and airflow heat exchange, and the installation of the thermal insulation buffer ensures that the operation of one exhaust pipe will not affect the working environment of the other exhaust pipe.

[0052] In addition, the cylinder wall of the thermal insulation buffer is made of an oxygen-compatible material, capable of withstanding temperatures ranging from 91K to 425K. A certain path length must be maintained between the inlet and outlet of the thermal insulation buffer to meet the requirements of heat conduction and insulation. This creates a thermal bridge between the pipes at both ends of the thermal insulation buffer, thereby protecting the upstream and downstream components of the thermal insulation buffer container from the impact of severe high and low temperature alternations. In particular, it maintains stable operating conditions for downstream valve equipment, preventing valve malfunctions due to temperature fluctuations and ensuring the normal operation of the rocket's liquid oxygen storage tank.

[0053] Based on the above embodiments, in a preferred embodiment, such as Figure 1As shown, the cryogenic high-flow-rate exhaust pipeline also includes an exhaust balancer 28. The exhaust balancer 28 is located downstream of the exhaust valve 16 and is connected to the outside. The exhaust balancer 28 is a component that uses a symmetrical exhaust method. Its exhaust path cross-section is often T-shaped, allowing the exhaust gas to be discharged in at least two opposite directions, thereby offsetting the thrust force on the pipeline generated by the gas during high-flow-rate discharge. When the gas flow rate is small, the thrust force of the discharged gas on the pipeline is often not a major concern. However, during the rocket fueling stage or the post-processing stage of the propellant tank in the later stages of the test, the exhaust volume is very large and there is a certain pressure. Installing the exhaust balancer 28 can protect the relevant pipeline from damage to the pipeline components caused by the huge exhaust thrust force.

[0054] Based on the above embodiments, in a preferred embodiment, such as Figure 1 As shown, both the safety valve 17 and the exhaust valve 16 are pneumatically controlled valves with a closing action chamber 13 and an opening action chamber 14. To monitor whether the valve action is performed correctly, a proximity sensor is installed at the valve actuator. The sensor signal transmits valve position information to the control system via the valve position signal line 15. The valves are pneumatically controlled rather than electrically controlled because, for rocket ground propulsion system testing, pneumatic valves offer better performance in terms of explosion-proof performance and electromagnetic interference. This embodiment specifically uses a nitrogen cylinder 1, along with a filter 2, a gas source shut-off valve 3, a pressure reducer 4, a pressure gauge 5, and related gas supply lines 6 to supply gas to the pneumatically controlled valves. Compared to a valve using unidirectional pneumatic drive with spring reset, this embodiment uses a valve with independent gas chambers for both opening and closing actions, resulting in faster response speeds and higher reliability of action execution.

[0055] Based on the above embodiments, in a preferred embodiment, such as Figure 1As shown, the closing chamber 13 of both pneumatic control valves is supplied with air by normally open 2-position 3-way solenoid valves, while the opening chamber 14 is supplied with air by normally closed 2-position 3-way solenoid valves. Specifically, the closing chamber 13 of the exhaust valve 16 receives closing control air from the first normally open 2-position 3-way solenoid valve 9, and its opening chamber 14 receives opening control air from the first normally closed 2-position 3-way solenoid valve 10. Similarly, the closing chamber 13 of the safety valve 17 receives closing control air from the second normally open 2-position 3-way solenoid valve 11, and its opening chamber 14 receives opening control air from the second normally closed 2-position 3-way solenoid valve 12. Compared to conventional mechanical safety valves, pneumatic valves also have inherent drawbacks, such as longer response times and a certain lag in remote control opening time. To effectively eliminate the impact of response lag and narrow the gap in response time compared to conventional safety valves, this device reduces response time by designing a reasonable pneumatic valve control air supply method. Specifically, it has the following advantages: 1. Using two 2-position 3-way solenoid valves to drive two actuating chambers respectively, compared to using a single 2-position 5-way solenoid valve to drive one reciprocating chamber, the system response is faster, reducing the reaction time of the solenoid valve supplying / removing control airflow and making the pneumatic control valve more sensitive. 2. The control logic is consistent with the usage logic, and the control states of the two solenoid valves are consistent, greatly optimizing the program control flow. Specifically, when neither solenoid valve is powered, the normally open solenoid valve and the closed chamber of the pneumatic valve are filled with control air, while the normally closed solenoid valve and the open chamber of the pneumatic valve are in the de-aired state, and the pneumatic valve is in the closed state. When both solenoid valves are powered synchronously, the normally open solenoid valve is closed, the closed chamber of the pneumatic valve is in the de-aired state, and the normally closed solenoid valve is open, the open chamber of the pneumatic valve is filled with control air, and the pneumatic valve is in the open state. When the pneumatic valve is open, the control signal simultaneously powers both 2-position 3-way solenoid valves; when the pneumatic valve is closed, the control signal simultaneously de-energizes both 2-position 3-way solenoid valves. If the pneumatic valve needs to perform the opening or closing action, it can be achieved simply by simultaneously powering or de-energizing the solenoid valves.

[0056] Based on the above embodiments, in a preferred embodiment, such as Figure 1As shown, each normally open 2-position 3-way solenoid valve and normally closed 2-position 3-way solenoid valve is communicatively connected to the control system. The control system sends or disconnects action signals simultaneously to the normally open and normally closed 2-position 3-way solenoid valves belonging to the same pneumatic control valve via the solenoid valve control signal line 8, thereby controlling the opening or closing of the corresponding pneumatic control valve. As mentioned above, the control system can open or close the valve by simultaneously powering or de-energizing the two auxiliary solenoid valves of the corresponding pneumatic control valve, simplifying the control logic and enabling the corresponding control to be completed in some situations without the use of complex control electrical components. This embodiment specifically employs a control system composed of components such as a closed-loop control computer 7, a relay combination 21, a PLC slave station 22, a PLC master station 23, an emergency control console 24, and an optical terminal switch 25, which is controlled by a ground control system.

[0057] Based on the above embodiments, in a preferred embodiment, such as Figure 1 As shown, the low-temperature high-flow-rate exhaust pipe and the safety function exhaust pipe are connected to the same interface located at the top of the liquid oxygen storage tank 20 via a tee. This arrangement simplifies the piping layout and reduces the number of openings in the storage tank.

[0058] Example 2

[0059] This embodiment provides a method for venting the liquid oxygen storage tank of a rocket body. Using the liquid oxygen storage tank venting system of the rocket body described in Embodiment 1, the method selects the corresponding low-temperature high-flow-rate venting pipeline and the safety function venting pipeline by judging the venting requirements and venting medium parameters at different venting stages.

[0060] In one embodiment, the safety function exhaust pipe includes the following operating steps:

[0061] S01: Set the pressure range (P1, P2) of liquid oxygen storage tank 20.

[0062] S02: Collect the air cushion pressure Pt inside the top of the liquid oxygen storage tank 20, i.e. Figure 1 The reading of pressure sensor 19 in the oxygen tank.

[0063] S03: When Pt≥P2, open the safety valve 17 to release the gas.

[0064] S04: Continue venting until Pt = P1, then close the safety valve 17.

[0065] The above steps can be used to control the function of the safety valve in the liquid oxygen storage tank 20.

[0066] Based on the above embodiments, in a preferred embodiment, such as Figure 2 As shown, step S01 includes the following steps:

[0067] a. Based on the pressure required for stable operation of the rocket engine in the liquid oxygen tank 20, set the ideal pressure range (P1', P2').

[0068] b. The sum of the pressure signal transmission time, the control system electrical signal response transmission time, the solenoid valve action time, and the control gas filling time of the valve action chamber is set as the inherent response time Δt.

[0069] c. Determine the pressure change value of liquid oxygen storage tank 20 within the time interval Δt; the pressure change value of liquid oxygen storage tank 20 during the opening of safety valve 17 is δP; the pressure change value of liquid oxygen storage tank 20 during the closing of safety valve 17 is δP'.

[0070] d. Set the final pressure range (P1, P2), P1 = P1' - δP, P2 = P2' + δP'.

[0071] As mentioned earlier, pneumatic valves have inherent drawbacks compared to conventional mechanical safety valves, such as longer response times and a certain lag in remote control action. This method, by testing the inherent response time and adjusting the pressure overshoot accordingly, effectively eliminates the impact of pneumatic valve response lag, reduces the response time difference, and improves system agility.

[0072] Based on the above embodiments, in a preferred embodiment, step c includes:

[0073] 1) The test setting for the safety function valve 17 is P3 when it opens and P3' when it closes.

[0074] 2) The pressure of liquid oxygen storage tank 20 (or the inlet pressure of safety valve 17) is increased at a certain pressurization rate v. When it reaches P3, safety valve 17 starts to open. After the inherent reaction time Δt, the pressure value of liquid oxygen storage tank 20 when safety valve 17 is actually opened is measured as P4. The overshoot of pressurization pressure δP = P4 - P3 is calculated.

[0075] 3) The pressure of liquid oxygen storage tank 20 (or the inlet pressure of safety valve 17) is reduced at a certain exhaust rate v'. When it reaches P3', safety valve 17 begins to close. After the inherent reaction time Δt, the pressure value of liquid oxygen storage tank 20 when safety valve 17 is actually closed is measured as P4'. The exhaust pressure overshoot δP' = P4' - P3' is calculated.

[0076] 4) Test the actual opening pressure value P4 and actual closing pressure value P4' corresponding to n different pressurization rates v and exhaust rates v'. Then, under different pressurization rates v and exhaust rates v', within Δt time, the difference between the set opening / closing pressure value of the n corresponding safety function valves 17 under the tank pressurization / exhaust conditions and the tank pressure value after the valve actually operates can be obtained, that is, the pressurization pressure overshoot δP and / or exhaust pressure overshoot δP'.

[0077] 5) The internal program of the control system calculates the pressurization rate v or exhaust rate v' of the liquid oxygen storage tank 20 in real time based on the data from the oxygen tank pressure sensor 19, and calculates or directly uses the corresponding δP or δP' obtained from steps 3 and 4 based on the current pressurization rate v or exhaust rate v'.

[0078] Since the inherent reaction time Δt includes the control system reaction time, the inherent response time of the solenoid valve, and the control chamber filling time, involving at least three different system devices, this inherent reaction time Δt, which pertains to overall performance, is difficult to accurately determine through theoretical calculations or related tests under the influence of multiple factors. To eliminate the influence of the system's inherent reaction time Δt, this implementation method is designed with the intended use in mind. Its purpose is to avoid tank pressure overshoot caused by pneumatic valve lag. Therefore, to prevent pressure from exceeding the adjustment expectation, the difference δP / δP' between the set opening / closing pressure value P3 / P3' of the pneumatic valve at the tank pressurization rate v / exhaust rate v' and the tank pressure value P4 / P4' after the valve's actual operation is directly tested. Multiple sets of tests are used to improve the universality of δP / δP', and the difference method can be used to calculate δP / δP' within the corresponding range but not actually measured, thus meeting the requirements of various control scenarios. In this way, the problem of valve response time lag is solved by using pressure overshoot to compensate for inherent time error, and a reliable and high-performance pressure range (P1, P2) can be obtained with less experimental cost.

[0079] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A liquid oxygen storage tank exhaust system for an arrow body, characterized in that, include: The low-temperature, high-flow exhaust pipeline is connected at the top of the liquid oxygen storage tank (20) and is suitable for exhausting high-flow-rate low-temperature oxygen. The low-temperature high-flow exhaust pipeline includes a first heat-insulating buffer (26) and an exhaust valve (16) connected in sequence; the exhaust valve (16) is a low-temperature oxygen valve; the first heat-insulating buffer (26) is a cylindrical container, and the inner diameter of the first heat-insulating buffer (26) is larger than the pipe inner diameter required for the maximum flow rate of exhaust during the filling stage; The safety function exhaust pipe is connected at the top of the liquid oxygen storage tank (20) and is connected in parallel with the low temperature high flow exhaust pipe, and is suitable for high temperature oxygen exhaust; the flow rate of the safety function exhaust pipe meets the emergency exhaust flow rate required by the liquid oxygen storage tank (20) during the rocket ignition stage when the pressure is over-adjusted; the safety function exhaust pipe includes a second heat insulation buffer (27) and a safety function valve (17) connected in sequence; the safety function valve (17) is a pneumatic control valve; the second heat insulation buffer (27) is a cylindrical container, and the inner diameter of the second heat insulation buffer (27) is larger than the inner diameter of the pipe required for the emergency exhaust flow rate; An oxygen tank pressure sensor (19) is installed on top of the liquid oxygen storage tank (20); The control system is in communication with the oxygen tank pressure sensor (19) and the safety function valve (17).

2. The exhaust system for the liquid oxygen storage tank of the rocket body according to claim 1, characterized in that, The low-temperature, high-flow exhaust pipeline also includes an exhaust balancer (28); the exhaust balancer (28) is located downstream of the exhaust valve (16) and is connected to the outside.

3. The exhaust system for the liquid oxygen storage tank of the rocket body according to claim 1, characterized in that, Both the safety function valve (17) and the exhaust valve (16) are pneumatic control valves with a closing action chamber (13) and an opening action chamber (14).

4. The exhaust system for the liquid oxygen storage tank of the rocket body according to claim 3, characterized in that, The closing control gas of the exhaust valve (16) is supplied by the first normally open two-position three-way solenoid valve (9), and the opening control gas of the exhaust valve (16) is supplied by the first normally closed two-position three-way solenoid valve (10).

5. The exhaust system for the liquid oxygen storage tank of the rocket body according to claim 4, characterized in that, The closing control air of the safety function valve (17) is supplied by the second normally open two-position three-way solenoid valve (11), and the opening control air of the safety function valve (17) is supplied by the second normally closed two-position three-way solenoid valve (12).

6. The exhaust system for the liquid oxygen storage tank of the rocket body according to claim 5, characterized in that, Each normally open 2-position 3-way solenoid valve and normally closed 2-position 3-way solenoid valve is communicatively connected to the control system. The control system simultaneously sends action signals to the normally open and normally closed 2-position 3-way solenoid valves belonging to the same pneumatic control valve, thereby opening the corresponding pneumatic control valve. The control system simultaneously disconnects the action signals to the normally open and normally closed 2-position 3-way solenoid valves belonging to the same pneumatic control valve, thereby closing the corresponding pneumatic control valve.

7. The exhaust system for the liquid oxygen storage tank of the rocket body according to any one of claims 1 to 6, characterized in that, The low-temperature high-flow exhaust pipe and the safety function exhaust pipe are connected to the same interface located on the top of the liquid oxygen storage tank (20) via a tee.

8. A method for venting liquid oxygen storage tanks in rocket bodies, characterized in that, Using the liquid oxygen storage tank exhaust system of the rocket body according to any one of claims 1 to 7, by determining the exhaust demand and exhaust medium parameters at different exhaust stages, a low-temperature high-flow exhaust pipeline and a safety function exhaust pipeline of corresponding specifications are selected; the working steps of the safety function exhaust pipeline are as follows: S01: Set the pressure range (P1, P2) of the liquid oxygen storage tank (20); S02: Collect the air cushion pressure Pt inside the top of the liquid oxygen storage tank (20); S03: When Pt≥P2, open the safety valve (17) to release the gas; S04: Continue venting until Pt = P1, then close the safety valve (17).

9. The method for venting the liquid oxygen storage tank of the rocket body according to claim 8, characterized in that, Step S01 includes the following steps: a. Based on the pressure of the liquid oxygen tank (20) required for stable operation of the rocket engine, set the ideal value of the pressure range (P1', P2'); b. The sum of the pressure signal transmission time, the control system electrical signal response transmission time, the solenoid valve action time, and the control gas filling time of the valve action chamber is set as the inherent response time Δt; c. Determine the pressure change value of the liquid oxygen storage tank (20) within the time interval Δt; the pressure change value of the liquid oxygen storage tank (20) during the opening of the safety function valve (17) is δP; the pressure change value of the liquid oxygen storage tank (20) during the closing of the safety function valve (17) is δP'. d. Set the final pressure range (P1, P2) as follows: P1 = P1' - δP, P2 = P2' + δP'.

10. The method for venting the liquid oxygen storage tank of the rocket body according to claim 9, characterized in that, Step c includes: 1) The test setting for the safety function valve (17) is to open the pressure value P3, and the test setting for the safety function valve (17) is to close the pressure value P3'; 2) The pressure of the liquid oxygen storage tank (20) is increased at a certain pressurization rate v. When it reaches P3, the safety function valve (17) starts to open. After the inherent reaction time Δt, the pressure value of the liquid oxygen storage tank (20) when the safety function valve (17) is actually opened is measured to be P4. The overshoot of the pressurization pressure δP = P4 - P3 is calculated. 3) The pressure of the liquid oxygen storage tank (20) is reduced at a certain exhaust rate v'. When it reaches P3', the safety function valve (17) starts to close. After the inherent reaction time Δt, the pressure value of the liquid oxygen storage tank (20) when the safety function valve (17) is actually closed is measured to be P4'. The exhaust pressure overshoot δP' = P4' - P3' is calculated. 4) Test the actual opening pressure value P4 and actual closing pressure value P4' corresponding to n different boost rates v and exhaust rates v'. Then, the pressure overshoot δP and δP' corresponding to n groups can be obtained under different boost rates v and exhaust rates v' within Δt time. 5) The control system calculates the pressurization rate v or exhaust rate v' of the liquid oxygen storage tank (20) in real time based on the data from the oxygen tank pressure sensor (19), and directly uses the corresponding δP or δP' obtained from step 4 or calculated by the difference method based on the calculated current pressurization rate v or exhaust rate v'.

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