阅读说明：本技术 液体火箭发动机试验推进剂供应系统水击抑制系统及方法 (Water hammer suppression system and method for liquid rocket engine test propellant supply system ) 是由 丁佳伟 冷海峰 寇兴华 贺宏 乔江晖 王乃世 邹伟龙 郭浩 张俊锋 耿直 朱小江 于 2021-06-29 设计创作，主要内容包括：本发明涉及一种液体火箭发动机试验推进剂供应系统水击抑制系统及方法。克服现有泄压方式应用在推进剂供应系统水击压力抑制过程中存在的工作量大、操作不便、存在安全风险以及泄压效果不明显的问题。系统包括水击压力泄放装置、充气管路、充气阀门、放气平衡腔、放气管路、放气阀门、压力传感器及推进剂回收容器；通过水击压力泄放装置调节关机水击压力,可将系统关机水击压力峰由70MPa量级降至40MPa以下,系统水击能力降低80％,避免试车过程中水击压力对系统及产品的破坏,在保证水击泄放系统响应迅速、可靠的同时对试车过程发动机的工作不造成影响,规避了技术风险,保证了试车顺利进行。(The invention relates to a water hammer suppression system and method for a propellant supply system in a liquid rocket engine test. The problems that the existing pressure relief mode is applied to the water hammer pressure suppression process of a propellant supply system, and the problems of large workload, inconvenience in operation, safety risk and unobvious pressure relief effect are solved. The system comprises a water hammer pressure relief device, an inflation pipeline, an inflation valve, a deflation balance cavity, an deflation pipeline, a deflation valve, a pressure sensor and a propellant recovery container; the shutdown water hammer pressure is adjusted through the water hammer pressure relief device, the shutdown water hammer pressure peak of the system can be reduced to be lower than 40MPa from 70MPa, the water hammer capacity of the system is reduced by 80%, the damage of the water hammer pressure to the system and products in the trial run process is avoided, the water hammer pressure in the trial run process is ensured to be quick and reliable, meanwhile, the work of an engine in the trial run process is not influenced, the technical risk is avoided, and the smooth running of the trial run is ensured.)

1. The utility model provides a liquid rocket engine test propellant supply system water hammer restraint system which characterized in that: comprises a water hammer pressure relief device (1), an inflation pipeline (2), an inflation valve (3), a deflation balance cavity (6), a deflation pipeline (4), a deflation valve (5), a pressure sensor and a propellant recovery container (7);

the water hammer pressure relief device (1) comprises a shell (11), a cylinder top cover (12), an inlet flange shoulder ring (15), a piston base (14) and a piston (13);

the shell (11) comprises an air cavity shell and a liquid cavity shell which are integrally arranged, and the flow area of the air cavity shell is larger than that of the liquid cavity shell; the joint of the air cavity shell and the liquid cavity shell is provided with a vent hole along the radial direction; a liquid outlet along the radial direction of the liquid cavity shell is arranged on the liquid cavity shell; the cylinder top cover (12) is fixed at one end of the air cavity shell; the cylinder top cover (12) is provided with three interfaces communicated with the air cavity shell; an inlet flange shoulder ring (15) is fixed at one end of the liquid cavity shell through a flange (16); the piston base (14) is matched and fixed in the liquid cavity shell with the inlet flange shoulder ring (15); the tail of the piston (13) is positioned in the air cavity, the outer peripheral surface of the tail of the piston (13) is sealed with the inner wall of the air cavity shell through a sealing structure, the head of the piston (13) is positioned in the liquid cavity, the outer peripheral surface of the head of the piston (13) is sealed with the inner wall of the liquid cavity shell through a sealing structure, and meanwhile, when the head of the piston (13) is tightly pressed with the piston base (14), the liquid discharge port is sealed;

an inlet flange shoulder ring (15) of the water hammer pressure relief device (1) is connected with a three-way pipeline, and two ports of the three-way pipeline are respectively used for being connected with a main propellant pipeline and a main engine valve (9);

the inflation pipeline (2) is connected with one of the interfaces on the cylinder top cover (12) of the water hammer pressure relief device (1), and the inflation valve (3) is arranged on the inflation pipeline (2);

the air release balance cavity (6) is connected with one of the interfaces on the cylinder top cover (12) of the water hammer pressure release device (1) through an air release pipeline (4), and an air release valve (5) is arranged on the air release pipeline (4);

the pressure sensor is connected with one interface on the cylinder top cover (12) of the water hammer pressure relief device (1);

the propellant recovery container (7) is connected with a liquid outlet of the water hammer pressure relief device (1).

2. The liquid rocket engine test propellant supply system water hammer suppression system of claim 1, wherein: the piston (13) and the piston base (14) are sealed through a sealing line.

3. The liquid rocket engine test propellant supply system water hammer suppression system of claim 2, wherein: and overlaying the cobalt-based hard alloy on the sealing line part, and processing the welding line part to the size after overlaying.

4. A liquid rocket engine test propellant supply system water hammer suppression system as claimed in claim 3, wherein: an O-shaped sealing ring and an aluminum gasket are adopted between the outer wall of the piston base (14) and the inner wall of the liquid cavity shell for sealing.

5. The liquid rocket engine test propellant supply system water hammer suppression system according to any one of claims 1-4, wherein: the ratio of the air cavity flow area to the liquid cavity flow area was 6.25.

6. The liquid rocket engine test propellant supply system water hammer suppression system of claim 5, wherein: two liquid discharge ports are uniformly distributed on the liquid cavity shell.

7. The liquid rocket engine test propellant supply system water hammer suppression system of claim 6, wherein: the number of the vent holes is four, and the vent holes are uniformly distributed on the air cavity shell.

8. The liquid rocket engine test propellant supply system water hammer suppression system of claim 7, wherein: the sealing device is an O-shaped sealing ring.

9. The liquid rocket engine test propellant supply system water hammer suppression system of claim 8, wherein: the shell (11), the cylinder top cover (12) and the inlet flange shoulder ring (15) in the water hammer pressure relief device (1) are made of S30408 stainless steel; the O-shaped sealing ring material of the piston base (14) is S8101/carboxyl nitroso, so that the compatibility with the propellant is ensured; the O-shaped sealing ring material at the position of the piston (13) close to the air cavity is nitrile rubber, and the O-shaped sealing ring material at the position close to the liquid cavity is S8101/carboxyl nitroso.

10. A water hammer suppression method for a propellant supply system in a liquid rocket engine test is characterized by comprising the following steps:

step 1, determining the corresponding relation between the air cavity pressure and the liquid cavity pressure;

determining the opening pressure of a liquid cavity liquid outlet corresponding to the air cavity inflated to different pressures according to the air cavity overflowing area and the liquid cavity overflowing area;

step 2, determining the pressure of an air cavity before the engine is started;

selecting a liquid cavity pressure P1, wherein P1 is more than 30 MPa; taking the pressure of the air cavity corresponding to the P1 as the pressure of the air cavity before starting the engine;

step 3, before the engine is started, inflating the air cavity;

before the engine is started, the air charging valve is opened to charge the air cavity of the water hammer pressure release device to p1, and the pressure is kept in the test run process;

step 4, balancing the pressure of the air cavity before the engine is shut down;

before the engine is shut down, an air cavity air release valve is opened, the air cavity pressure is balanced to p2, the liquid cavity pressure corresponding to p2 is less than 30MPa, when the system is shut down, the liquid cavity water hammer pressure exceeds 30MPa, a liquid discharge port is opened, the liquid cavity pressure is released, and the released propellant is discharged into a recovery container through a recovery pipeline;

and 5, after the water hammer pressure is released, when the system pressure is recovered to be below 30MPa, the piston of the water hammer pressure release device automatically returns to the seat under the action of the p2 air pressure, and the liquid discharge port is closed.

Technical Field

The invention relates to a water hammer suppression method for a propellant supply system in an engine test, in particular to a water hammer suppression system and a water hammer suppression method for a propellant supply system in a large-flow high-pressure extruded liquid rocket engine test.

Background

In a conventional large-flow high-pressure extruded liquid rocket engine test, when the engine is started and shut down, a propellant supply system can generate water hammer pressure related to flow and pressure. In the starting process of the engine, the water hammer pressure generated by the propellant supply system needs to reach 30MPa, and the engine can be normally started. When the engine is shut down, the water hammer pressure generated by the propellant supply system can reach 70MPa or higher when the response time of the valve is 10ms magnitude and the flow is large. At pressures above 70MPa, water hammer pressure poses a significant risk to the reliability of the engine inlet valve, propellant supply system valve, test system clamp bracket.

Therefore, it is necessary to research the water hammer pressure suppression technology of the propellant supply system aiming at the characteristics and test requirements of the test system, so that when the engine is shut down, the water hammer pressure generated by the propellant supply system is relieved, the peak value of the water hammer pressure is reduced, and the damage of the water hammer pressure to the system and products in the test run process is avoided; meanwhile, the pressure relief can not influence the starting and working processes of the engine, the technical risk is avoided, and the smooth running-in is ensured.

The conventional high-flow high-pressure extruded liquid rocket engine test propellant is a highly toxic propellant capable of spontaneous combustion, so that the safety valve air-through liquid-discharging mode cannot be adopted. Meanwhile, the test run task requires ignition for multiple times in one day, if a blasting diaphragm pressure relief mode is adopted, the pipeline needs to be emptied and blown off after ignition is completed every time, so that the blasting diaphragm can be replaced, the workload is high, the operation is inconvenient, and huge safety risks are brought. In addition, the shutdown water hammer needs to be inhibited, and meanwhile, the pressure relief measure does not influence the startup process (the startup water hammer is 30MPa), so if the safety valve is adopted for emptying liquid drainage or the blasting diaphragm is adopted for water hammer pressure relief, the set pressure needs to be increased to be more than 30MPa, the response speed is low, and the pressure relief effect is not obvious.

Disclosure of Invention

The invention aims to provide a water hammer suppression system and a water hammer suppression method for a high-flow high-pressure extruded liquid rocket engine test propellant supply system, and aims to solve the problems of large workload, inconvenience in operation, safety risk and unobvious pressure release effect in the water hammer pressure suppression process of the propellant supply system in the conventional pressure release mode.

The technical scheme of the invention is to provide a water hammer suppression system of a large-flow high-pressure extruded liquid rocket engine test propellant supply system, which is characterized in that: the device comprises a water hammer pressure relief device, an inflation pipeline, an inflation valve, a deflation balance cavity, an air relief pipeline, an air relief valve, a pressure sensor and a propellant recovery container;

the water hammer pressure relief device comprises a shell, a cylinder top cover, an inlet flange shoulder ring, a piston base and a piston;

the shell comprises an air cavity shell and a liquid cavity shell which are integrally arranged, and the flow area of the air cavity shell is larger than that of the liquid cavity shell; the joint of the air cavity shell and the liquid cavity shell is provided with a vent hole along the radial direction; a liquid outlet along the radial direction of the liquid cavity shell is arranged on the liquid cavity shell; the cylinder top cover is fixed at one end of the air cavity shell; the top cover of the cylinder is provided with three interfaces communicated with the air cavity shell; the inlet flange shoulder ring is fixed at one end of the liquid cavity shell through a flange; the piston base is matched and fixed in the liquid cavity shell with the inlet flange shoulder ring; the tail part of the piston is positioned in the air cavity, and the peripheral surface of the tail part of the piston is sealed with the inner wall of the air cavity shell through a sealing structure; the piston head is positioned in the liquid cavity, the outer peripheral surface of the piston head is sealed with the inner wall of the liquid cavity shell through a sealing structure, and meanwhile, when the piston head is tightly pressed with the piston base, the liquid discharge port is blocked;

an inlet flange shoulder ring of the water hammer pressure relief device is connected with a three-way pipeline, and two ports of the three-way pipeline are respectively used for being connected with a main propellant pipeline and a main engine valve;

the inflation pipeline is connected with one interface on the top cover of the cylinder of the water hammer pressure relief device, and the inflation valve is arranged on the inflation pipeline;

the air release balance cavity is connected with one of the interfaces on the top cover of the cylinder of the water hammer pressure release device through an air release pipeline, and an air release valve is arranged on the air release pipeline;

the pressure sensor is connected with one interface on the top cover of the water hammer pressure relief device cylinder;

the propellant recovery container is connected with a liquid outlet of the water hammer pressure relief device.

Further, realize sealed through the sealing line between piston and the piston base, when piston head and piston base compress tightly, guarantee through the line seal that liquid does not let out through the leakage fluid dram in the liquid cavity.

Further, the cobalt-based hard alloy is welded on the sealing line part in a surfacing mode, and the welding line part is machined to be in size after the surfacing is completed, so that the difference of the hardness of the sealing line between the piston and the base is guaranteed.

Furthermore, an O-shaped sealing ring and an aluminum gasket are adopted between the outer wall of the piston base and the inner wall of the liquid cavity shell for sealing, so that the sealing reliability is ensured.

Further, the ratio of the air cavity flow area to the liquid cavity flow area was 6.25.

Furthermore, two liquid discharge ports are uniformly distributed on the liquid cavity shell.

Furthermore, the number of the vent holes is four, and the vent holes are uniformly distributed on the air cavity shell.

Further, the sealing device is sealed by an O-shaped ring, so that gas and liquid cannot flow into the cavity.

Furthermore, the shell, the cylinder top cover and the inlet flange shoulder ring in the water hammer pressure relief device are made of S30408 stainless steel; the O-shaped sealing ring material of the piston base is S8101/carboxyl nitroso group, so that the compatibility with a propellant is ensured; the O-shaped sealing ring material at the position of the piston close to the air cavity is made of butadiene-acrylonitrile rubber, and the O-shaped sealing ring material at the position close to the liquid cavity is made of S8101/carboxyl nitroso.

The invention also provides a water hammer suppression method for the test propellant supply system of the high-flow high-pressure extruded liquid rocket engine, which is characterized by comprising the following steps of:

step 1, determining the corresponding relation between the air cavity pressure and the liquid cavity pressure;

determining the corresponding liquid cavity pressure capable of opening the liquid discharge port when the air cavity is inflated to different pressures according to the overflowing area of the air cavity and the overflowing area of the liquid cavity;

step 2, determining the pressure of an air cavity before the engine is started;

selecting a liquid cavity pressure P1, wherein P1 is more than 30 MPa; taking the pressure of the air cavity corresponding to the P1 as the pressure of the air cavity before starting the engine;

step 3, before the engine is started, inflating the air cavity;

before the engine is started, the air charging valve is opened to charge the air cavity of the water hammer pressure release device to p1, and the pressure is kept in the test run process;

step 4, balancing the pressure of the air cavity before the engine is shut down;

before the engine is shut down, an air cavity air release valve is opened, the air cavity pressure is balanced to p2, the liquid cavity pressure corresponding to p2 is less than 30MPa, when the system is shut down, the liquid cavity water hammer pressure exceeds 30MPa, a liquid discharge port is opened, the liquid cavity pressure is released, and the released propellant is discharged into a recovery container through a recovery pipeline;

and 5, after the water hammer pressure is released, when the system pressure is recovered to be below 30MPa, the piston of the water hammer pressure release device automatically returns to the seat under the action of the p2 air pressure, and the liquid discharge port is closed.

The invention has the beneficial effects that:

1. the water hammer pressure suppression system is connected to the front end of the engine, the shutdown water hammer pressure is adjusted through the water hammer pressure relief device, the shutdown water hammer pressure peak of the system can be reduced to be below 40MPa from 70MPa, the water hammer capacity of the system is reduced by 80%, damage of the water hammer pressure to the system and products in the trial run process is avoided, quick and reliable response of the water hammer relief system is guaranteed, meanwhile, the work of the engine in the trial run process is not affected, technical risks are avoided, and the trial run is guaranteed to be carried out smoothly.

2. Through debugging and trial run verification, the water hammer pressure relief device has a correct principle, and compared with the water hammer pressure relief device adopting a safety valve for emptying and discharging liquid or a blasting diaphragm for water hammer pressure relief, the setting pressure of the water hammer pressure relief device is less than 30MPa, the response speed block is high, the pressure relief effect is obvious, and the adjustment is simple.

Drawings

FIG. 1 is a schematic diagram of a water hammer pressure relief system of the present invention;

FIG. 2 is a schematic view of the water hammer pressure relief device of the present invention;

FIG. 3 is a schematic diagram of an air cavity balancing system of the present invention;

the reference numbers in the figures are: 1-water hammer pressure relief device, 2-inflation pipeline, 3-inflation valve, 4-deflation pipeline, 5-deflation valve, 6-deflation balance cavity, 7-propellant recovery container, 8-propellant supply system, 9-engine main valve;

11-shell, 12-cylinder top cover, 13-piston, 14-piston base, 15-inlet flange shoulder ring, 16-flange, 17-first O-shaped sealing ring, 18-second O-shaped sealing ring and 19-third O-shaped sealing ring.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, specific embodiments accompanied with figures are described in detail below, and it is apparent that the described embodiments are a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making creative efforts based on the embodiments of the present invention, shall fall within the protection scope of the present invention.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Furthermore, the present invention is described in detail with reference to the drawings, and in the detailed description of the embodiments of the present invention, the cross-sectional view illustrating the structure of the device is not enlarged partially according to the general scale for convenience of illustration, and the drawings are only exemplary and should not be construed as limiting the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

Meanwhile, in the description of the present invention, it should be noted that the terms "upper, lower, inner and outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation and operate, and thus, cannot be construed as limiting the present invention. Furthermore, the terms "first, second, or third" are used merely to describe a day, and are not to be construed as indicating or implying relative importance.

The terms "mounted, connected and connected" in the present invention are to be understood broadly, unless otherwise explicitly specified or limited, for example: can be fixedly connected, detachably connected or integrally connected: they may be mechanically, electrically, or directly connected, or indirectly connected through intervening media, or may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, the water hammer pressure relief system of the present embodiment is arranged in front of an engine inlet, and includes a water hammer pressure relief device 1, an inflation pipeline 2, an inflation valve 3, an air bleed pipeline 4, an air bleed valve 5, an air bleed balance cavity 6, a pressure sensor, a propellant recovery container 7, and the like. The inlet at the front end of the water hammer pressure discharge system is connected with a DN50 tee joint which is respectively connected with a propellant supply system 8 and an engine main valve 9. The water hammer pressure relief device 1 comprises an air cavity and a liquid cavity, wherein the inlet end of the liquid cavity is the inlet at the front end of the water hammer pressure relief system, the inlet end of the air cavity is connected with an inflation pipeline 2, an air relief pipeline 4 and a pressure sensor, and an inflation valve 3 and an air relief valve 5 are respectively arranged on the inflation pipeline 2 and the air relief pipeline 4. The pressure of the air cavity of the water hammer pressure relief device 1 can be adjusted through the inflation pipeline 2, the inflation valve 3, the air relief pipeline 4 and the air relief valve 5, and the relief port is opened to perform drainage when the water hammer pressure of the liquid cavity is higher than the pressure of the air cavity.

The concrete structure of the water hammer pressure relief device 1 is shown in fig. 2, and comprises a shell 11, a cylinder top cover 12, an inlet flange shoulder ring 15, a piston base 14 and a piston 13; the shell 11 comprises an air cavity shell and a liquid cavity shell which are integrally arranged, and the flow area of the air cavity shell is larger than that of the liquid cavity shell; in this embodiment, the drift diameter of the air cavity is DN100, and the ratio of the flow area of the air cavity shell to the flow area of the liquid cavity shell is 6.25. The connection between the air chamber housing and the liquid chamber housing is provided with vent holes along the radial direction, and the first 4 vent holes are uniformly distributed on the air chamber housing in the embodiment and used for discharging the air in the cavity part between the piston 13 and the housing 11 when the piston 13 moves. Be equipped with on the sap cavity casing along its radial leakage fluid dram for flowing back when water hammer pressure is released, this embodiment sets up two symmetrical DN32 leakage fluid dram in the middle section of the sap cavity casing. The cylinder head cover 12 is fixed to one end of the air cavity housing. Referring to fig. 1, the cylinder head cover 12 is provided with three DN10 straight joints communicating with the air chamber housing for connecting the inflation line 2, the deflation line 4 and the pressure sensor, which can be used for inflation and deflation of the air chamber and pressure measurement, respectively. An inlet flange shoulder ring 15 is bolted to one end of the chamber housing by means of a flange 16. The piston base 14 is fixed inside the liquid chamber shell in a matching way with the inlet flange shoulder ring 15. Two seals of an O-shaped sealing ring and an aluminum gasket are adopted between the piston base 14 and the shell 11, so that the sealing reliability is ensured. The tail part of the piston 13 is positioned in the air cavity, and the peripheral surface of the tail part of the piston 13 is sealed with the inner wall of the air cavity shell through a sealing structure; the head of the piston 13 is positioned in the liquid cavity, and the peripheral surface of the head of the piston 13 is sealed with the inner wall of the liquid cavity shell through a sealing structure. Two O-shaped ring seals are arranged on the piston 13 to ensure that gas and liquid cannot flow into the cavity.

The shell 11, the cylinder top cover 12 and the inlet flange shoulder ring 15 of the water hammer pressure relief device are all made of S30408 stainless steel; the bolt is made of 30CrMnSi high-strength stainless steel; the O-shaped sealing ring (a first O-shaped sealing ring 17) of the piston base 14 is made of S8101/carboxyl nitroso, so that the compatibility with a propellant is ensured; the O-shaped sealing ring (a third O-shaped sealing ring 19) at the position close to the air cavity of the piston 13 is made of butadiene-acrylonitrile rubber, and the O-shaped sealing ring (a second O-shaped sealing ring 18) at the position close to the liquid cavity is made of S8101/carboxyl nitroso.

Cleaning and degreasing each part of the water hammer pressure relief device 1 with alcohol before assembly, purging with dry nitrogen, and leaving no visible excess in the inner cavity; 7804 lubricating grease is coated on the O-shaped sealing ring and the sealing part of the inner wall of the shell 11 in the assembling process, and after the O-shaped sealing ring and the sealing part are assembled, the flexible movement of the valve is checked without clamping stagnation; after the assembly is finished, the air cavity is subjected to a 10MPa air tightness test, the liquid cavity is subjected to a 40MPa water pressure strength test, and the air cavity is cleaned by blowing after the test.

When the device works, the inlet flange shoulder ring 15 of the water hammer pressure discharge device 1 is connected with a three-way pipeline, two ports of the three-way pipeline are respectively connected with a propellant supply system 8 and an engine main valve 9, and the pressure of an air cavity is adjusted in real time through the inflation pipeline 2 and the gas discharge pipeline 4. When the pressure of the air cavity acts on the piston 13 and the pressure of the air cavity is greater than the water hammer pressure of the liquid cavity, the piston 13 is tightly pressed with the piston base 14, and liquid in the cavity is ensured not to be discharged through the liquid discharge port through line sealing. And the cobalt-based hard alloy is welded on the sealing line of the piston 13 in a surfacing mode, and the welding is processed to a size after the surfacing is finished, so that the difference of the hardness of the sealing line between the piston 13 and the base is ensured. When the water hammer pressure of the liquid cavity is greater than the pressure of the air cavity, the piston 13 moves leftwards, liquid is discharged through a gap between the piston 13 and the piston base 14, flows out through two symmetrical DN32 liquid discharge ports, and is connected to the propellant recovery container 7.

In order to meet the requirement of gas pressure balance during deflation, an air cavity balance system shown in fig. 3 is established, a stainless steel pipe 75mm with phi 108 x 4.5 is used as a deflation balance cavity 6, the air cavity of the water hammer pressure relief device 1 keeps high pressure in the starting and working processes of test run, and the air release valve 5 is opened to balance the pressure of the air cavity to required low pressure before the test run is shut down.

Test method

Step 1, determining the corresponding relation between the air cavity pressure and the liquid cavity pressure;

the air cavity flow area and the liquid cavity flow area ratio are 6.25 in this embodiment, different liquid cavity pressures are determined through a gas-liquid cavity pressure test, the air cavity is inflated to different pressures, the corresponding liquid cavity pressure capable of opening the liquid discharge port is obtained, and the air cavity pressure corresponds to the liquid discharge port and opens the liquid cavity pressure as shown in table 1.

TABLE 1 air cavity pressure corresponding to liquid discharge port opening liquid cavity pressure comparison table

Step 2, determining the pressure of an air cavity before the engine is started;

in table 1, when the air cavity is inflated to 5.4MPa, the corresponding liquid cavity pressure capable of opening the liquid discharge port is 32MPa, and the water hammer pressure of the liquid cavity when the engine is started is required to be 30MPa, so that in the starting process of the engine, when the air cavity pressure is 5.4MPa, the water hammer pressure of the liquid cavity can be ensured to be 30MPa, and at the moment, the water hammer pressure of the liquid cavity is less than 32MPa, the liquid discharge port is not opened, and the starting process of the engine is not affected. Therefore, the pressure of the air cavity is determined to be 5.4MPa before the engine is started.

Step 3, before the engine is started, inflating the air cavity;

before the engine is started, the air cavity of the water hammer pressure relief device 1 is inflated to 5.4MPa by opening the inflation valve 3, and the pressure is kept in the test run process.

Step 4, balancing the pressure of the air cavity before the engine is shut down;

before the engine is shut down, the air cavity air release valve is opened, the air cavity is balanced to 1.5MPa, when the system is shut down, the liquid discharge port is opened after the water hammer pressure of the liquid cavity exceeds 9.8MPa, the water hammer pressure is discharged, and the discharged propellant is discharged into a recovery container through a recovery pipeline. After the water hammer pressure is released, when the water hammer pressure of the liquid cavity is recovered to be below 9.8MPa, the piston 13 of the water hammer pressure release device 1 automatically returns to the seat under the action of 1.5MPa of air pressure, and the liquid discharge port is closed.

Here, in other embodiments, the air cavity may also be balanced to any pressure value below 5MPa in table 1. For example, when the air cavity is balanced to 0.5MPa, and when the system is shut down and the water hammer pressure of the liquid cavity exceeds 4MPa, the liquid outlet is opened. After the water hammer pressure is released, when the water hammer pressure of the liquid cavity is recovered to be lower than 4MPa, the piston 13 of the water hammer pressure release device 1 automatically returns to the seat under the action of 0.5MPa of air pressure, and the liquid discharge port is closed. For another example, when the air cavity is balanced to 5MPa and the system is shut down, the liquid discharge port is opened when the water hammer pressure of the liquid cavity exceeds 29.8 MPa. After the water hammer pressure is released, when the water hammer pressure of the liquid cavity is recovered to be below 29.8MPa, the piston 13 of the water hammer pressure release device 1 automatically returns to the seat under the action of 5MPa of air pressure, and the liquid discharge port is closed.

Compared with the prior art, the pressure relief device adopts a safety valve to discharge liquid through air or explode the diaphragm to perform water hammer pressure relief, the setting pressure of the pressure relief device is less than 30MPa, the speed block is responded, and the pressure relief effect is obvious.

According to verification, the water hammer pressure peak of the system can be reduced to be lower than 40MPa from 70MPa, the water hammer capacity of the system is reduced by 80%, damage of the water hammer pressure to the system and products in the trial run process is avoided, quick and reliable response of the water hammer discharge system is guaranteed, meanwhile, the work of an engine in the trial run process is not affected, technical risks are avoided, and the trial run is guaranteed to be carried out smoothly.