Exhaust system and method for rocket body liquid oxygen storage tank

Abstract

The invention provides a rocket body liquid oxygen storage tank exhaust system and a method thereof. The exhaust system comprises: a low-temperature large-flow exhaust pipeline, the head end of which is communicated with the top of the liquid oxygen storage tank and is suitable for large-flow low-temperature oxygen exhaust; the head end of the safety function exhaust pipeline is communicated with the top of the liquid oxygen storage tank, the safety function exhaust pipeline and the low-temperature large-flow exhaust pipeline are connected in parallel, and the safety function exhaust pipeline is suitable for high-temperature oxygen exhaust; the flow of the safety function exhaust pipeline meets the emergency exhaust flow required by the liquid oxygen storage tank during pressure overshoot in the rocket body ignition stage; the oxygen tank pressure sensor is arranged at the top of the liquid oxygen storage tank; and the control system is in communication connection with the oxygen tank pressure sensor and the safety function valve. The exhaust system can respond to different exhaust requirements of the rocket body liquid oxygen storage tank in different stages, the exhaust requirement of a large amount of low-temperature oxygen steam in the large-flow filling stage can be met, and meanwhile the requirement of emergency exhaust of high-temperature oxygen can be met in the power system test stage.

Description

Technical Field

[0001] The present invention relates to the technical field of ground power system testing of rocket core-stage modules, and in particular to a rocket body liquid oxygen tank exhaust system and a method thereof. Background Art

[0002] Liquid oxygen is a commonly used propellant medium for launch vehicles. As the thrust of launch vehicles continues to increase, the demand for liquid oxygen is also increasing, and thus the exhaust requirements for liquid oxygen tanks are also increasing. In order to meet the test requirements of the rocket body liquid oxygen tank power system, the ground system needs to be equipped with corresponding exhaust devices. The ground exhaust system needs to adapt to the large amount of low-temperature oxygen vapor discharge during the filling stage, and also needs to adapt to the need for emergency discharge of high-temperature gas due to pressure overshoot in the liquid oxygen tank during the working stage. The temperature, pressure, and flow rate of the exhaust are different at different stages, especially during the pressure overshoot process during the test, and there are also requirements for the exhaust response speed to avoid damage caused by overpressure in the rocket body liquid oxygen tank. However, the existing liquid oxygen tank exhaust system only has a single exhaust pipeline, which is difficult to adapt to different working conditions. Summary of the invention

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

[0004] In order to solve the above technical problems, the present application provides a rocket body liquid oxygen tank exhaust system, comprising:

[0005] The cryogenic and high-flow exhaust pipeline, the head end of which is connected to the top of the liquid oxygen storage tank, is suitable for exhausting a large flow of cryogenic oxygen; the cryogenic and high-flow exhaust pipeline comprises a first insulation buffer and an exhaust valve connected in sequence; the exhaust valve is a cryogenic oxygen valve; the first insulation buffer is a cylindrical container with an insulated outer wall, and the inner diameter of the first insulation buffer is larger than the inner diameter of the pipeline required for the maximum flow of exhaust gas during the filling stage;

[0006] The head end of the insurance function exhaust pipeline is connected to the top of the liquid oxygen tank and is in parallel with the low-temperature large-flow exhaust pipeline; the flow of the insurance function exhaust pipeline meets the emergency exhaust flow required by the liquid oxygen tank when the pressure is over-regulated during the rocket body ignition stage, and the insurance function exhaust pipeline includes a second insulation buffer and an insurance function valve connected in sequence front and back; the insurance function valve is a pneumatic control valve; the second insulation buffer is a cylindrical container, and the inner diameter of the second insulation buffer is larger than the inner diameter of the pipeline required for the emergency exhaust flow;

[0007] Oxygen tank pressure sensor, installed on the top of the liquid oxygen tank;

[0008] The control system is in communication with the oxygen tank pressure sensor and the insurance function valve.

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

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

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

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

[0013] Furthermore, the closing cavity control air of the safety function valve is supplied by the second normally open two-position three-way solenoid valve, and the opening cavity 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 two-position three-way solenoid valve and normally closed two-position three-way solenoid valve is communicatively connected to the control system; the control system simultaneously sends action signals to the normally open two-position three-way solenoid valve and the normally closed two-position three-way solenoid valve belonging to the same pneumatic control valve, thereby realizing the opening of the corresponding pneumatic control valve; the control system simultaneously disconnects the action signals to the normally open two-position three-way solenoid valve and the normally closed two-position three-way solenoid valve belonging to the same pneumatic control valve, thereby realizing the closing of the corresponding pneumatic control valve.

[0015] Furthermore, the low-temperature large-flow exhaust pipeline and the insurance function exhaust pipeline are connected to the same interface located at the top of the liquid oxygen tank through a tee.

[0016] A method for exhausting a rocket body liquid oxygen tank uses the above-mentioned rocket body liquid oxygen tank exhaust system, and selects a low-temperature, high-flow exhaust pipeline and a safety function exhaust pipeline of corresponding specifications by judging the exhaust requirements and exhaust medium parameters at different exhaust stages; the working steps of the safety function exhaust pipeline are as follows:

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

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

[0019] S03: When Pt≥P2, open the insurance function valve to exhaust;

[0020] S04: Keep exhausting until Pt=P1, and then close the safety function valve.

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

[0022] a. Set the ideal value of the pressure range (P1', P2') according to the liquid oxygen tank pressure required for the stable operation of the rocket engine;

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

[0024] c. Determine the pressure change value of the liquid oxygen tank within the time Δt; when the safety valve is opened, the pressure change value of the liquid oxygen tank is δP; when the safety valve is closed, the pressure change value of the liquid oxygen tank is δP';

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

[0026] Further, step c comprises:

[0027] 1) The opening pressure value of the insurance function valve test is set to P3, and the closing pressure value of the insurance function valve test is set to P3';

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

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

[0030] 4) Test the actual opening pressure value P4 and the actual closing pressure value P4' corresponding to n groups of different boosting rates v and exhaust rates v', and then obtain the corresponding pressure overshoot δP and δP' of n groups within Δt time under different boosting rates v and exhaust rates v';

[0031] 5) The control system calculates the pressurization rate v or exhaust rate v' of the liquid oxygen tank in real time according to the oxygen tank pressure sensor data, and directly uses the corresponding δP or δP' obtained from step 4 or calculated by the difference method according to 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 tank exhaust system provided by the present invention, by arranging a low-temperature and large-flow exhaust pipeline, a safety function exhaust pipeline, an oxygen tank pressure sensor and a control system, makes the low-temperature and large-flow exhaust pipeline suitable for quickly relieving the pressure of the tank, and the safety function exhaust pipeline can be used as a safety valve device; thereby, the adverse effects of alternating exhaust of low-temperature oxygen and high-temperature oxygen on equipment characteristics can be avoided, the requirements for response time of exhaust in each stage are solved, and the risk of overpressure in the rocket body liquid oxygen tank is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0036] Figure 2 1 is a flow chart of theoretical calculation steps for setting the pressure range of the liquid oxygen tank in Example 2 of the present invention.

[0037] Description of reference numerals:

[0038] 1-nitrogen cylinder, 2-filter, 3-gas source stop valve, 4-pressure reducer, 5-pressure gauge, 6-gas supply pipeline, 7-closed-loop control computer, 8-solenoid valve control signal line, 9-first normally open two-position three-way solenoid valve, 10-first normally closed two-position three-way solenoid valve, 11-second normally open two-position three-way solenoid valve, 12-second normally closed two-position three-way solenoid valve, 13-closing action chamber, 14-opening action chamber, 15-valve position signal line; 16-exhaust valve, 17-safety function valve, 18-reducing joint; 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-discharge balancer. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] It should be noted in the description of the present invention that the coordinate system used in this specification when describing the orientation is determined by the posture of the main view of the corresponding component, and the naming of the observation angle of the corresponding view is also based on this. Therefore, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. in this specification indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In addition, 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 a rocket body liquid oxygen tank exhaust system.

[0045] In one embodiment, Figure 1 As shown, it includes: a low-temperature large-flow exhaust pipeline, a safety function exhaust pipeline, an oxygen box pressure sensor 19 and a control system.

[0046] The head end of the cryogenic and high-flow exhaust pipeline is connected to the top of the liquid oxygen tank 20, which is suitable for exhausting a large flow of cryogenic oxygen, and is usually also used to release excess oxygen generated by endothermic evaporation during the static stage of the rocket. The cryogenic and high-flow exhaust pipeline includes a first insulation buffer 26 and an exhaust valve 16 connected in sequence; the exhaust valve 16 is a cryogenic oxygen valve; the first insulation buffer 26 is a cylindrical container, and the inner diameter of the first insulation buffer 26 is larger than the inner diameter of the pipeline required for the maximum flow of exhaust during the filling stage.

[0047] The head end of the insurance function exhaust pipeline is also connected to the top of the liquid oxygen tank 20, and is in parallel with the low-temperature and large-flow exhaust pipeline. The flow of the insurance function exhaust pipeline meets the emergency exhaust flow required by the liquid oxygen tank 20 when the pressure is overshot during the rocket body ignition stage, and is suitable for high-temperature oxygen exhaust. When the pipeline faces components of different specifications, a reducer 18 can be used to connect. The insurance function exhaust pipeline includes a second insulation buffer 27 and an insurance function valve 17 connected in sequence front and back. The insurance function valve 17 is a high-temperature oxygen type pneumatic control valve. The structure of the second insulation buffer 27 is similar to that of the first insulation buffer 26, and its inner diameter is larger than the inner diameter of the pipeline required for the emergency exhaust flow.

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

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

[0050] The insurance function exhaust pipeline of the device plays the insurance function of the internal pressure of the liquid oxygen tank 20. By setting insurance function valves 17 of different specifications, it can meet the exhaust requirements of different flow rates. The insurance function valve 17 adopts a pneumatic valve and remotely controls its opening and closing, rather than a conventional mechanical insurance valve. This can avoid the uncontrollable factors caused by the conventional mechanical insurance valve only sensing the tank pressure through its own mechanical structure. For example, when a conventional mechanical insurance valve faces a hot and cold alternating working environment, the temperature difference may cause the size and properties of the pressure sensing components of the mechanical structure to change, thereby causing the response pressure and speed of the insurance discharge action of the entire valve body to change, and even cause mechanical failure. In addition, pneumatic valve products suitable for high-temperature oxygen are easier to obtain from the market, and the working performance is more reliable.

[0051] In addition, the working state of the exhaust interface of the rocket body liquid oxygen tank 20 and its connecting pipeline is often intermittent, and the flow rate or medium state in the pipeline is dynamically adjusted, so the pipeline may be filled with a large amount of low-temperature oxygen steam at times, and may be high-temperature oxygen with a certain pressure at times, so its pipeline and related components will face high and low temperature alternating working states, and improper handling may cause valve failure, tank overpressure and other accidents. Therefore, the exhaust device connected to the exhaust interface of the rocket body liquid oxygen tank 20 is divided into two parts: a low-temperature large-flow exhaust pipeline and a safety function exhaust pipeline. The rocket body liquid oxygen tank 20 is connected to the low-temperature large-flow exhaust pipeline and the safety function exhaust pipeline through a three-way. At the front end of the valve equipment of the two exhaust pipelines, a first insulation buffer 26 and a second insulation buffer 27 are respectively set to isolate the influence of the exhaust medium of the rocket body liquid oxygen tank 20 on the downstream of the insulation buffer. Specifically, because the insulation buffer has a certain volume, a pressure buffer can be formed, thereby avoiding heat exchange between the inlet and outlet gases of the buffer during the static stage. There is a certain path length distance between the inlet and outlet positions of the thermal insulation buffer, thereby isolating the low temperature / high temperature of the front and rear end pipelines of the thermal insulation buffer and avoiding heat conduction through the pipe wall. Therefore, the setting of the thermal insulation buffer can avoid the temperature impact of pipeline heat conduction and airflow heat exchange on the downstream of the pipeline, and the setting of the thermal insulation buffer ensures that when any exhaust pipeline is working, it will not affect the working environment of the other exhaust pipeline.

[0052] In addition, the wall of the thermal insulation buffer is made of oxygen-compatible material and can withstand a temperature range of 91K-425K. There must be a certain path length between the inlet and outlet of the thermal insulation buffer to meet the requirements of thermal conduction and insulation. This will form a blocking thermal bridge between the pipelines 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 alternation, especially maintaining the working conditions of the downstream valve equipment stable, avoiding valve failure caused by temperature, and ensuring the normal operation of the rocket body liquid oxygen tank.

[0053] Based on the above implementation, in a preferred implementation, Figure 1As shown, the low-temperature, high-flow exhaust pipeline also includes an exhaust balancer 28; the exhaust balancer 28 is arranged 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 to exhaust gas. The exhaust path cross-section is often T-shaped, which can make the exhaust gas be discharged in at least two opposite directions, so that the reverse thrust on the pipeline formed when the gas is discharged at a large flow rate can be offset. When the gas flow rate is small, the reverse thrust of the exhaust gas on the pipeline does not need to be paid too much attention. However, in the rocket filling stage or the tank post-processing stage in the later stage of the test, the exhaust volume is very large and there is a certain pressure. After the exhaust balancer 28 is set, the relevant pipelines can be protected from damage to the pipeline components by the huge exhaust reverse thrust.

[0054] Based on the above implementation, in a preferred implementation, Figure 1 As shown, the insurance function valve 17 and the exhaust valve 16 are both pneumatic control valves with a closing action chamber 13 and an opening action chamber 14. In order to monitor whether the valve action is executed in place, a proximity reaction sensor is set at the valve actuator, and the sensor signal transmits the valve position information to the control system through the valve position signal line 15. The reason why the valve is pneumatically controlled rather than electrically controlled is that for the rocket ground power system test, the pneumatic valve has better performance in explosion-proof performance, electromagnetic interference, etc. This embodiment specifically uses a nitrogen bottle 1 and cooperates with a filter 2, an air source stop valve 3, a pressure reducer 4, a pressure gauge 5 and related air supply pipelines 6 to supply air to the pneumatic control valve. Compared with the solution that the valve adopts a one-way air pressure drive with a spring reset, the valve of this embodiment adopts a solution that both the opening and closing actions have independent air cavities, which can obtain a faster response speed and higher action execution reliability.

[0055] Based on the above implementation, in a preferred implementation, Figure 1As shown, the closing action chambers 13 of the two pneumatic control valves are both supplied with air by a normally open two-position three-way solenoid valve, while the opening action chambers 14 are both supplied with air by a normally closed two-position three-way solenoid valve. Specifically, the closing action chamber 13 of the exhaust valve 16 is supplied with closing chamber control air through the first normally open two-position three-way solenoid valve 9, and its opening action chamber 14 is supplied with opening chamber control air by the first normally closed two-position three-way solenoid valve 10. The closing action chamber 13 of the safety function valve 17 is supplied with closing chamber control air through the second normally open two-position three-way solenoid valve 11, and its opening action chamber 14 is supplied with opening chamber control air by the second normally closed two-position three-way solenoid valve 12. Compared with conventional mechanical safety valves, pneumatic valves also have their own inherent defects, such as longer response time and a certain lag in the opening time of remote control. In order to effectively eliminate the influence of response lag and narrow the gap in response time with conventional safety valves, this device reduces the response time by designing a reasonable pneumatic valve control gas supply method. Specifically, it has the following advantages: First, two two-position three-way solenoid valves are used to drive two action chambers respectively. Compared with the scheme of using a two-position five-way solenoid valve to drive a reciprocating action chamber, the system response can be faster, reducing the reaction time of the solenoid valve supply / withdrawal control airflow, making the response speed of the pneumatic control valve more sensitive; Second, the control logic is consistent with the use logic, and the control state of the two solenoid valves is consistent, which greatly optimizes the program control process. It is specifically embodied in: when both solenoid valves are not powered, the closed chamber of the normally open solenoid valve and the pneumatic valve is full of control gas, while the open chamber of the normally closed solenoid valve and the pneumatic valve is in the exhaust state, and the pneumatic valve is in the closed state. After the two solenoid valves are powered synchronously, the normally open solenoid valve is closed, the closed chamber of the pneumatic valve is in the exhaust state, and the normally closed solenoid valve is opened, the open chamber of the pneumatic valve is full of control gas, and the pneumatic valve is in the open state. When the pneumatic valve is opened, the control signal supplies power to the two two-position three-way solenoid valves at the same time. When the pneumatic valve is closed, the control signal cuts off the power to the two two-position three-way solenoid valves at the same time. If the pneumatic control valve needs to be opened or closed, it can be achieved by simply supplying or cutting off the power to the solenoid valves at the same time.

[0056] Based on the above implementation, in a preferred implementation, Figure 1As shown, each normally open two-position three-way solenoid valve and normally closed two-position three-way solenoid valve are connected to the control system for communication; the control system simultaneously sends or disconnects the action signal to the normally open two-position three-way solenoid valve and the normally closed two-position three-way solenoid valve belonging to the same pneumatic control valve through the solenoid valve control signal line 8, thereby controlling the opening or closing of the corresponding pneumatic control valve. As just mentioned above, the control system can realize the opening or closing of the valve by simultaneously powering on or off the two auxiliary solenoid valves of the corresponding pneumatic control valve, simplifying the control logic, so that in some cases, even without using complex control electrical components, the corresponding control can be completed. This embodiment specifically adopts 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, and is controlled by a ground control system.

[0057] Based on the above implementation, in a preferred implementation, Figure 1 As shown, the low temperature and large flow exhaust pipeline and the insurance function exhaust pipeline are connected to the same interface located at the top of the liquid oxygen tank 20 through a tee. This arrangement can simplify the pipeline layout and reduce the number of tank openings.

[0058] Example 2

[0059] The present embodiment provides a method for exhausting a rocket body liquid oxygen tank, using the rocket body liquid oxygen tank exhaust system described in Example 1, by judging the exhaust requirements and exhaust medium parameters at different exhaust stages, selecting a low-temperature, high-flow exhaust pipeline and a safety function exhaust pipeline of corresponding specifications.

[0060] In one embodiment, the safety function exhaust line includes the following working steps:

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

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

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

[0064] S04: Keep exhausting until Pt=P1, and then close the safety function valve 17.

[0065] Through the above steps, the control of the safety valve function of the liquid oxygen storage tank 20 can be achieved.

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

[0067] a. Set the ideal value of the pressure range (P1', P2') according to the liquid oxygen tank 20 pressure required for the rocket engine to work stably.

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

[0069] c. Determine the pressure change value of the liquid oxygen tank 20 within the time Δt; when the safety function valve 17 is opened, the pressure change value of the liquid oxygen tank 20 is δP; when the safety function valve 17 is closed, the pressure change value of the liquid oxygen tank 20 is δP'.

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

[0071] As mentioned before, pneumatic valves also have their own inherent defects compared to conventional mechanical safety valves, such as longer response time and a certain lag in the action time of remote control. However, this method effectively eliminates the impact of pneumatic valve response lag, narrows the response time gap, and improves system agility by testing the pressure overshoot of the inherent response time and then setting the corresponding pressure band interval.

[0072] Based on the above implementation, in a preferred embodiment, step c comprises:

[0073] 1) The opening pressure value of the safety function valve 17 is set to P3 when testing, and the closing pressure value of the safety function valve 17 is set to P3' when testing;

[0074] 2) The pressure of the liquid oxygen tank 20 (the inlet pressure of the safety function valve 17 can also be tested) is increased at a certain pressure increase rate v. When it reaches P3, the safety function valve 17 starts to open. After an inherent reaction time Δt, the pressure value of the liquid oxygen tank 20 when the safety function valve 17 is actually opened is measured to be P4, and the overshoot of the pressure increase δP=P4-P3 is calculated;

[0075] 3) The pressure of the liquid oxygen tank 20 (the inlet pressure of the safety function valve 17 can also be tested) is reduced at a certain exhaust rate v'. When it reaches P3', the safety function valve 17 starts to close. After an inherent reaction time Δt, the pressure value of the liquid oxygen tank 20 when the safety function valve 17 is actually closed is measured to be P4', and the exhaust pressure overshoot δP'=P4'-P3' is calculated;

[0076] 4) Testing n groups of actual opening pressure values ​​P4 and actual closing pressure values ​​P4' corresponding to different boosting rates v and exhaust rates v', and then obtaining the difference between the set opening / closing pressure value of the n groups of corresponding insurance function valves 17 under tank boosting / exhausting conditions and the tank pressure value after the valve is actually actuated within a time Δt, i.e., the boosting pressure overshoot δP and / or the 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 tank 20 in real time based on the data of the oxygen tank pressure sensor 19, and calculates the corresponding δP or δP' obtained from steps 3 and 4 by the difference method or directly adopts 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 device, the control air cavity filling time, etc., it involves at least three different sets of system equipment. Under the influence of multiple factors, this inherent reaction time Δt belonging to the overall performance is difficult to accurately know through theoretical calculation or related tests. In order to eliminate the influence of the system inherent reaction time Δt, this implementation method is guided by the purpose of use. Its purpose is to avoid the overshoot of the tank pressure caused by the delayed response of the pneumatic valve. Therefore, in order to avoid the pressure 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 is actually completed is directly tested, and the universality of δP / δP' is improved through multiple groups of tests, and the difference method can be used to calculate the δP / δP' in the corresponding interval but not measured, so as to meet the requirements of various control scenarios. In this way, the problem of valve response time lag is solved by using the method of compensating the inherent time error by using the pressure overshoot, and a reliable pressure range (P1, P2) with good performance can be obtained with less experimental cost.

[0079] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A rocket liquid oxygen tank exhaust system, characterized in that: include: A low-temperature, high-flow exhaust pipeline, the head end of which is connected to the top of the liquid oxygen storage tank (20), and is suitable for exhausting a large flow of low-temperature oxygen; The low-temperature, high-flow exhaust pipeline comprises 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 inner diameter of the pipeline required for the maximum exhaust flow rate in the filling stage; The head end of the insurance function exhaust pipeline is connected to the top of the liquid oxygen tank (20), and is in parallel with the low-temperature large-flow exhaust pipeline, and is suitable for high-temperature oxygen exhaust; the flow of the insurance function exhaust pipeline meets the emergency exhaust flow required by the liquid oxygen tank (20) when the pressure is over-regulated during the rocket body ignition stage, and the insurance function exhaust pipeline includes a second insulation buffer (27) and an insurance function valve (17) connected in sequence front and back; the insurance function valve (17) is a pneumatic control valve; the second insulation buffer (27) is a cylindrical container, and the inner diameter of the second insulation buffer (27) is larger than the inner diameter of the pipeline required for the emergency exhaust flow; An oxygen tank pressure sensor (19) is arranged on the top of the liquid oxygen tank (20); The control system is communicatively connected with the oxygen box pressure sensor (19) and the safety function valve (17).

2. The rocket body liquid oxygen tank exhaust system according to claim 1, characterized in that: The low-temperature, high-flow exhaust pipeline further comprises an exhaust balancer (28); the exhaust balancer (28) is arranged downstream of the exhaust valve (16) and is in communication with the outside.

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

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

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

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

7. The rocket body liquid oxygen tank exhaust system according to any one of claims 1 to 6, characterized in that: The low-temperature large-flow exhaust pipeline and the insurance function exhaust pipeline are connected to the same interface located at the top of the liquid oxygen storage tank (20) through a tee.

8. A method for exhausting liquid oxygen tank of a rocket body, characterized in that: Using the rocket body liquid oxygen tank exhaust system according to any one of claims 1 to 7, by judging the exhaust requirements 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: Setting the pressure range (P1, P2) of the liquid oxygen tank (20); S02: collecting the air cushion pressure Pt inside the top of the liquid oxygen tank (20); S03: When Pt≥P2, open the safety function valve (17) to exhaust; S04: Keep exhausting until Pt=P1, and then close the safety function valve (17).

9. The method for exhausting liquid oxygen tank of a rocket body according to claim 8, characterized in that: Step S01 includes the following steps: a. setting the ideal pressure range (P1', P2') according to the liquid oxygen tank (20) pressure required for the rocket engine to operate stably; b. The sum of the pressure signal transmission time, the control system electrical signal reaction transmission time, the solenoid valve action time, and the control gas filling time of the valve action chamber is set as the inherent reaction time Δt; c. Determine the pressure change value of the liquid oxygen tank (20) within the time Δt; when the safety function valve (17) is opened, the pressure change value of the liquid oxygen tank (20) is δP; when the safety function valve (17) is closed, the pressure change value of the liquid oxygen tank (20) is δP'; d. For the final pressure range (P1, P2), set P1 = P1'-δP, P2 = P2'+δP'.

10. The method for exhausting liquid oxygen tank of a rocket body according to claim 9, characterized in that: Step c includes: 1) The opening pressure value of the safety function valve (17) test is set to P3, and the closing pressure value of the safety function valve (17) test is set to P3'; 2) The pressure of the liquid oxygen tank (20) increases at a certain boosting rate v. When the pressure reaches P3, the safety function valve (17) starts to open. After an inherent reaction time Δt, the pressure value of the liquid oxygen tank (20) when the safety function valve (17) is actually opened is measured to be P4, and the boosting pressure overshoot δP=P4-P3 is calculated; 3) The pressure of the liquid oxygen tank (20) is reduced at a certain exhaust rate v'. When it reaches P3', the safety function valve (17) starts to close. After an inherent reaction time Δt, the pressure value of the liquid oxygen tank (20) when the safety function valve (17) is actually closed is measured to be P4', and the exhaust pressure overshoot δP'=P4'-P3' is calculated; 4) Test the actual opening pressure value P4 and the actual closing pressure value P4' corresponding to n groups of different boosting rates v and exhaust rates v', and then obtain the corresponding pressure overshoot δP and δP' of n groups within Δt time under different boosting rates v and exhaust rates v'; 5) The control system calculates the pressurization rate v or exhaust rate v' of the liquid oxygen tank (20) in real time based on the data of 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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