阅读说明：本技术 一种气动柱塞自增压单组元脉冲工作姿控发动机 (Pneumatic plunger self-pressurization single-component pulse working attitude control engine ) 是由 刘红军 于 2019-12-09 设计创作，主要内容包括：本发明公开了一种气动柱塞自增压单组元脉冲工作姿控发动机,由缸体、活塞、推力室、单向阀座和螺塞组成。单向阀座端头与控制阀连接,缸体、单向阀座和推力室螺纹连接,活塞在缸体内往复移动；活塞与缸体之间形成一个环腔和圆柱腔,环腔通过泄出口与外界相通作为低压腔,圆柱腔为高压腔。活塞中芯腔装有催化剂,活塞端头设置多排喷注孔。将气动柱塞泵与推力室结合成一体,通过推进剂催化分解产生气体驱动柱塞泵,利用活塞不平衡面积产生的压力差形成正反馈增压效应,利用不平衡面积形成压力差的气动柱塞泵形成自增压脉冲工作方式,大幅提高发动机推力室室压和降低推进剂贮箱供应压力,从而有效地提高发动机性能、降低结构重量。(The invention discloses a pneumatic plunger self-pressurization single-component pulse working attitude control engine which comprises a cylinder body, a piston, a thrust chamber, a one-way valve seat and a plug screw. The end of the one-way valve seat is connected with the control valve, the cylinder body, the one-way valve seat and the thrust chamber are in threaded connection, and the piston moves in the cylinder body in a reciprocating manner; an annular cavity and a cylindrical cavity are formed between the piston and the cylinder body, the annular cavity is communicated with the outside through a discharge port to serve as a low-pressure cavity, and the cylindrical cavity is a high-pressure cavity. The core cavity in the piston is filled with catalyst, and the end of the piston is provided with a plurality of rows of injection holes. The pneumatic plunger pump and the thrust chamber are combined into a whole, gas generated by catalytic decomposition of a propellant drives the plunger pump, a positive feedback pressurization effect is formed by utilizing pressure difference generated by unbalanced area of a piston, a self-pressurization pulse working mode is formed by utilizing the pneumatic plunger pump with the pressure difference formed by the unbalanced area, the pressure of the thrust chamber of the engine is greatly improved, the supply pressure of a propellant storage tank is reduced, and therefore the performance of the engine is effectively improved, and the structural weight is reduced.)

1. A pneumatic plunger self-pressurization single-component pulse working attitude control engine comprises a cylinder body, a piston, a thrust chamber, a one-way valve seat, a steel ball, a spring and a plug screw, and is characterized in that the end of the one-way valve seat is connected with a control valve, the cylinder body, the one-way valve seat and the thrust chamber are connected through threads, and the piston can reciprocate in the cylinder body; an annular cavity with the large diameter D and the small diameter D and a cylindrical cavity with the diameter D are formed between the piston and the cylinder body, the annular cavity is communicated with the outside through a discharge port and is a low-pressure cavity, and the cylindrical cavity with the diameter D is a high-pressure cavity; the cavity of the piston central core is filled with a catalyst and is sealed by a plug screw with a small hole, and the end of the piston is provided with a plurality of rows of injection holes; the pressure at which the combustion chamber reaches steady state is determined by the following equation:

where xi is from the cylinder to the combustion chamberCoefficient of equivalent flow resistance, p_oIs the cylinder chamber pressure, p_eAt ambient pressure, A_tIs the throat area of the thrust chamber, p_cIs the combustion chamber pressure, q_mFor propellant flow into the combustion chamber, RT_cGamma is the thermodynamic parameter of the gas in the combustion chamber; according to the above formula can be derived:

under the vacuum environment condition

The engine operating frequency depends on the piston stroke L and the displacement speed and can be determined by fluid dynamics simulation calculations.

2. The pneumatic plunger self-pressurization single-component pulse working attitude control engine as claimed in claim 1, wherein the single-component propellant which can be catalytically decomposed in the engine is high-concentration hydrogen peroxide or anhydrous hydrazine.

Technical Field

The invention relates to the technical field of rocket engine design, in particular to a single-component engine for attitude control of a satellite, a carrier rocket upper stage or a space vehicle.

Background

Attitude control engines are required to be arranged on satellites, carrier rockets or space vehicles to maintain and control flight attitudes, and attitude control engines using single elements capable of catalytically decomposing to generate fuel gas as propellants are widely used internationally due to the fact that the systems are relatively simple and have higher performance than cold air propulsion, such as attitude and orbit control systems of American Sedan D H2O2 auxiliary propulsion systems, Syncom II, Syncom III and morning bird aircrafts. The single-component catalytic decomposition attitude control engines adopt an extrusion supply mode, a high-pressure air source, a pressure reducing valve or a pressure regulator and the like are required to be arranged to maintain higher propellant storage tank supply pressure, the system is relatively complex, the higher the storage tank pressure is, the larger the required air source volume is, the heavier the system structure weight is, the room pressure of the attitude control engines is generally relatively lower, only 1-2 Mpa is obtained, and the engine performance is relatively low.

In order to eliminate a gas cylinder of a squeezing type propulsion system, a hydrogen peroxide gas generator cycle with a plunger pump is proposed in 2002 by Lawrence Livemore national laboratory in America (AIAA2002-3702), and the basic principle is that gas generated by catalytic decomposition of partial propellant at the rear part of the plunger pump is utilized to drive the plunger pump on one hand, and a storage tank is introduced to pressurize the storage tank on the other hand. The plunger pump is pressurized and then supplies one or more thrust chambers with catalyst beds. The boost pressure of the plunger pump is controlled by a regulator that regulates the gas flow. The gas that drives the plunger pump is finally discharged to the outside. The single-component propulsion system scheme can avoid the use of a high-pressure gas cylinder and realize the light weight of the propulsion system, but has the defects of two problems: one is that the gas for driving the plunger pump is directly discharged to the outside, so that certain energy loss exists, and the higher the system pressure is, the larger the energy loss is; and secondly, a flow regulator working in a high-temperature and high-pressure gas medium needs to be arranged, so that high reliability and high safety difficulty are realized, which are main factors for limiting the pressure level which can be reached by the propulsion system, and the maximum published test pressure is not more than 5 Mpa.

Disclosure of Invention

In order to avoid the defects in the prior art, the invention provides a pneumatic plunger self-pressurization single-component pulse working attitude control engine, which organically combines a pneumatic plunger pump and a thrust chamber into a whole, generates gas through catalytic decomposition of a propellant to drive the plunger pump, and forms a positive feedback pressurization effect by utilizing pressure difference generated by unbalanced areas of pistons; the pneumatic plunger pump which utilizes unbalanced area to form pressure difference forms a self-pressurization pulse working mode, so that the pressure of a thrust chamber of the engine is greatly improved, the supply pressure of a propellant storage tank is reduced, the performance of the engine is effectively improved, and the structural weight is reduced.

The invention solves the technical problem by adopting the technical scheme that the reciprocating piston comprises a cylinder body, a piston, a thrust chamber, a one-way valve seat, a steel ball, a spring and a screw plug, and is characterized in that the end of the one-way valve seat is connected with a control valve, the cylinder body, the one-way valve seat and the thrust chamber are connected through threads, and the piston can reciprocate in the cylinder body; an annular cavity with the large diameter D and the small diameter D and a cylindrical cavity with the diameter D are formed between the piston and the cylinder body, the annular cavity is communicated with the outside through a discharge port and is a low-pressure cavity, and the cylindrical cavity with the diameter D is a high-pressure cavity; the cavity of the piston central core is filled with a catalyst and is sealed by a plug screw with a small hole, and the end of the piston is provided with a plurality of rows of injection holes; the pressure at which the combustion chamber reaches steady state is determined by the following equation:

where xi is the equivalent flow resistance coefficient from the cylindrical cavity to the combustion chamber, p_oIs the cylinder chamber pressure, p_eAt ambient pressure, A_tIs the throat area of the thrust chamber, p_cIs the combustion chamber pressure, q_mFor propellant flow into the combustion chamber, RT_cGamma is the thermodynamic parameter of the gas in the combustion chamber; according to the above formula can be derived:

under the vacuum environment condition

The engine operating frequency depends on the piston stroke L and the displacement speed and can be determined by fluid dynamics simulation calculations.

The single-component propellant for the engine which can be catalytically decomposed is high-concentration hydrogen peroxide or anhydrous hydrazine.

Advantageous effects

The invention provides a pneumatic plunger self-pressurization single-component pulse working attitude control engine, which organically combines a pneumatic plunger pump and a thrust chamber into a whole, generates gas through catalytic decomposition of a propellant to drive the plunger pump, and forms a positive feedback pressurization effect by utilizing pressure difference generated by unbalanced areas of pistons, thereby enabling the engine to realize high-chamber pressure pulse working. The pneumatic plunger pump which utilizes unbalanced area to form pressure difference forms a self-pressurization pulse working mode, exhaust loss is avoided, the adjusting component works in a high-temperature and high-pressure medium, the pressure of a thrust chamber of the engine is greatly improved, the supply pressure of a propellant storage tank is reduced, and therefore the performance of the engine is effectively improved, and the structural weight of a propulsion system is reduced.

The pneumatic plunger self-pressurization single-component pulse working attitude control engine has the characteristics of low pressure of a storage box, only 0.3-0.5 Mpa, high pressure of a combustion chamber up to 20Mpa, high performance and small size, can be used as an upper-level attitude and orbit control power system of a satellite or a carrier, can greatly reduce the consumption of pressurized gas while ensuring the performance of the engine, effectively lightens the structural weight, and improves the safety and the reliability of the system.

Drawings

The invention relates to a pneumatic plunger self-pressurization single-component pulse working attitude control engine, which is further described in detail with reference to the accompanying drawings and an embodiment.

FIG. 1 is a schematic diagram of a pneumatic plunger self-pressurizing single-component pulse working attitude control engine.

Fig. 2 is a schematic view of the piston and plug screw assembly of the present invention.

Fig. 3 is a sectional view taken along line B-B of fig. 2.

In the drawings

1. Cylinder 2, piston 3, thrust chamber 4, one-way valve seat 5, steel ball 6, spring 7 and screw plug

Detailed Description

The embodiment is a pneumatic plunger self-pressurization single-component pulse working attitude control engine.

Referring to fig. 1, 2 and 3, the pneumatic plunger self-pressurizing single-component pulse working attitude control engine of the embodiment is composed of a cylinder body 1, a piston 2, a thrust chamber 3, a one-way valve seat 4, a steel ball 5, a spring 6 and a screw plug 7; wherein, the end of the one-way valve seat 4 is connected with a control valve, the cylinder body 1, the one-way valve seat 4 and the thrust chamber 3 are connected through threads, and the piston 2 can reciprocate in the cylinder body 1; an annular cavity with the major diameter D and the minor diameter D and a cylindrical cavity with the diameter D are formed between the piston 2 and the cylinder body 1, the annular cavity is communicated with the outside through a discharge port and is a low-pressure cavity, and the cylindrical cavity with the diameter D is a high-pressure cavity; a core cavity in the piston 2 is filled with a catalyst and is sealed by a plug screw 7 with a small hole, and the end of the piston is provided with a plurality of rows of injection holes;

the pressure at which the combustion chamber reaches steady state may be determined by the relationship:

where xi is the equivalent flow resistance coefficient from the cylindrical cavity to the combustion chamber, p_oIs the cylinder chamber pressure, p_eAt ambient pressure, A_tIs the throat area of the thrust chamber, p_cIs the combustion chamber pressure, q_mFor propellant flow into the combustion chamber, RT_cGamma is the thermodynamic parameter of the gas in the combustion chamber; according to the above formula can be derived:

under the vacuum environment condition

The working frequency of the engine mainly depends on the stroke L and the moving speed of the piston and can be determined according to fluid dynamic simulation calculation.

The single-component propellant for the attitude control engine which can be catalytically decomposed is high-concentration hydrogen peroxide or anhydrous hydrazine.

Taking a hydrogen peroxide propellant with the concentration of 90% as an example, winding a multilayer silver mesh catalyst into a catalyst cavity at the core part of the piston 2, screwing a screw plug 7, assembling an engine according to the tooling requirement, connecting a control valve at the left end of a one-way valve seat 4, and connecting an inlet of the control valve with a propellant pipeline led out from a storage tank. When the engine needs to work, the control valve is opened, the steel ball 5 can be pushed open under the pressure action of the hydrogen peroxide in the storage tank, the propellant enters the cylindrical cavity with the diameter d to push the piston to move rightwards, meanwhile, the propellant enters the catalyst bed through the throttling hole of the plug screw 7, and gas generated after catalysis is sprayed into the combustion chamber cavity of the thrust chamber through the jetting hole at the end of the piston; the piston stops after moving to contact with the end of the thrust chamber, and the pressure p of the combustion chamber is generated by the pressure holding effect of the throat part of the thrust chamber_cThe piston is acted leftwards, the piston moves leftwards due to the force difference formed by unbalanced area because the annular cavity is a low-pressure cavity, the pressure of the cylindrical cavity is increased, the steel ball 5 moves leftwards, the one-way valve is closed, the gas flow entering the combustion chamber is increased, and p is increased_cThe pressure of the cylindrical cavity is further increased, so that a positive feedback effect is formed, the combustion chamber reaches a high pressure level, and the gas is sprayed out through the spray pipe to generate thrust. When the piston moves to the end, the piston stops moving, the propellant entering the combustion chamber is cut off, the chamber pressure rapidly drops, and when the chamber pressure drops to the ambient pressure, the steel balls 5 move rightwardsThe movement, the check valve opens again, reciprocating in such a way that the engine operates in a pulsed manner. When the control valve is closed, the engine is shut down after the last pulse is completed.

The pressure at which the combustion chamber reaches steady state may be determined by the relationship:

where xi is the equivalent flow resistance coefficient from the cylindrical cavity to the combustion chamber, p_oIs the cylinder chamber pressure, p_eAt ambient pressure, A_tIs the throat area of the thrust chamber, p_cIs the combustion chamber pressure, q_mFor propellant flow into the combustion chamber, RT_cGamma is the thermodynamic parameter of the gas in the combustion chamber;

the above relationship can be derived:

under the vacuum environment condition

The working frequency of the engine mainly depends on the stroke L and the moving speed of the piston and can be determined according to fluid dynamic simulation calculation. The present example is designed according to single pulse thrust 50N, and the large diameter D of low-pressure cavity is 12mm, the diameter D of cylindrical cavity is 8mm, and the flow resistance coefficient from cylindrical cavity to combustion chamber is 0.81X 10³Pa·(s²/kg²)，The diameter of the throat part of the thrust chamber is 2.4mm, the diameter of the outlet of the spray pipe is 24mm, namely the area ratio of the spray pipe is 100, and 90 percent of hydrogen peroxide decomposition gas RT is obtained by thermodynamic calculation_c＝3.761×10⁵J/mol, Γ is 1.1418, calculated to obtain the combustion chamber pressure p under vacuum ambient conditions_c21.78Mpa, and determining the theoretical specific impulse Isp of the engine 1781.5m/s according to the calculation of thermal parameters.

In the embodiment, the piston stroke is 6mm, the calculated value of the average moving speed of the piston in the pulse working process is 0.40m/s, the pulse bandwidth is 15ms, the return time of the piston is calculated according to the inlet pressure of the control valve of 0.35Mpa, the time for filling the cylindrical cavity with the propellant is 5.8ms, and the working frequency of the engine is 48 Hz.