A one-way blowing based anti-backfire system for paste rocket engine

Abstract

The application provides a single-direction blowing-based anti-backfire system of a paste rocket engine, which comprises an adiabatic layer connected with a combustion chamber, an anti-backfire valve front cover, an anti-backfire valve shell, an anti-backfire valve bolt capable of moving forward and backward in the anti-backfire valve shell, and a gas path inlet and outlet installed on the anti-backfire valve shell. The single-direction blowing-based anti-backfire system of the paste rocket engine combines the high flexibility of a pure metal mechanical sealing mechanism and the high reliability of a pneumatic blowing system, can greatly avoid the anti-backfire failure caused by the fact that flexible structures (such as sealing rings) cannot withstand high temperatures, prolongs the service life of the anti-backfire mechanism, and makes it feasible to realize the repeated ignition of the engine more than 100 times. The mechanism lays a foundation for the future design of a thrust wide-range random-control adjustable paste vector rocket engine system due to its high reliability and long service life.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of rocket engine, and relates to a paste propellant rocket engine and a backfire prevention mechanism, in particular to a paste rocket engine backfire prevention system based on one-way blowing and mechanical sealing. BACKGROUND

[0002] The power device used by spacecraft or space carrier is mostly rocket engine, namely liquid propellant rocket engine and solid propellant rocket engine. The former has a complex structure and has the advantage of good controllability (controllability mainly refers to thrust adjustment, thrust vector control and engine multiple start); the latter has a simple structure and has the disadvantage of poor controllability. There is also a solid-liquid propellant rocket engine composed of solid fuel, liquid oxidizer or liquid fuel, solid oxidizer, which has a relatively complex structure, and compared with the liquid propellant rocket engine, it lacks a liquid supply system and needs further research for practical application. In order to attack targets in time and accurately, it is urgently required to improve the penetration ability and maneuverability of missile rocket engine. The aircraft using solid rocket engine as power device requires the engine to have functions of thrust adjustment, intelligent control and multiple start-stop, which is one of the development trends of future solid propellant rocket engine.

[0003] The advantages of paste propellant rocket engine are as follows:

[0004] High energy density: oxygen-fuel mixture + nano-metal particle high specific impulse propellant is adopted, which has high density (1.41 g / cm3) and high specific impulse (267 s); good ignition performance: plasma ignition device is adopted, which can effectively shorten the ignition delay and realize multiple controllable ignition; good storage performance: the paste system is stable, not sensitive to temperature, pressure and electricity, has no adhesive aging and aggregation effect, and is non-toxic and non-polluting; high thrust regulation ratio: the thrust regulation scheme of paste flow control combined with shaft bolt variable throat diameter is adopted, which can theoretically achieve a high thrust ratio of 10:1; good series performance: the structure is simple, a small amount of parameter modification can form a series of engine systems without redesign; good test support performance: the sampling of gas cylinder pressure and fuel physical and chemical performance test is simple and does not affect the normal work of the engine, and the engine is easy to maintain.

[0005] [1] Xiao Jinwu, Zhang Wengang. PEPA / AP paste propellant formula research [J]. Solid Rocket Technology, 2001 (04): 46-49. (This article mainly introduces the paste propellant formula based on PEPA / AP and its physical and chemical properties.)

[0006] [2] Shi Jian. Performance characteristics and application prospect of paste rocket engine [J]. Flying Missile, 2008 (10): 61-63. (This article mainly introduces the main advantages of current paste propellant rocket engine and its application direction.)

[0007] [3] YOON C. Injection dynamics of gelled propellants. [D]: Purdue University, 2011. (This article mainly introduces the dynamic characteristics of paste propellant under the extrusion supply, including the changes of its flow characteristics under high pressure extrusion.)

[0008] [4] QIN Z Y. Multi-pulse paste rocket engine working characteristics research [D]: Nanjing University of Technology, 2019. (This article mainly realizes the pulse work of paste propellant rocket engine through single / multi-pulse device, and writes a set of feasible internal ballistic simulation algorithm of paste propellant rocket engine)

[0009] [5] ANDERSON D J, JOHN D, et al. NASA In-Space advanced chemical propulsion development in recent years [C] / / 2010 IEEE Aerospace Conference, 2010: 1-20. (NASA's review paper on advanced chemical propulsion technology in recent years, which involves paste propellant rocket engine)

[0010] [6] YANG H. Paste rocket engine working characteristics test and simulation research [D]: Nanjing University of Technology, 2016. (Nanjing University of Technology's research paper on the working characteristics of paste propellant rocket engine system, which divides the working process of paste propellant rocket engine into three main stages, namely initial combustion stage, stable combustion stage and residual propellant combustion stage) SUMMARY

[0011] The paste rocket engine anti-backfire system based on one-way blowing provided by the present application combines the high flexibility characteristics of pure metal mechanical sealing mechanism and the high reliability characteristics of pneumatic blowing system, maximizes the anti-backfire performance, greatly avoids the anti-backfire failure caused by the inability of flexible structure (such as sealing ring) to withstand high temperature, prolongs the service life of the anti-backfire mechanism, and makes it possible for the engine to repeat ignition more than 100 times. This mechanism has high reliability and long service life, and lays a foundation for the design of future thrust wide-range controlled adjustable paste vector rocket engine system.

[0012] The present application is based on a high-temperature-resistant stainless steel sliding seal plug anti-reverse valve composed of a paste rocket engine system. Based on existing paste rocket engine technology, including pneumatic blowing technology and extrusion anti-reverse technology, the present application is combined with the existing paste vector rocket engine anti-reverse technology formed by the extrusion supply system.

[0013] The present application adopts pneumatic valve driving, and by replacing the traditional paste rocket engine system extrusion anti-reverse propellant supply system with the blowing anti-reverse system involved in the present application, the free shutdown of the paste rocket engine is realized, and in combination with the waste heat ignition system, the multiple high-frequency start-stop of the engine can be realized. Depending on the design of the engine combustion chamber, the maximum number of multiple ignitions can reach more than 100 times, realizing extremely high engine on-off controllable range and shutdown reliability.

[0014] The technical solution of the present application will be further described as follows:

[0015] The present application is a one-way blowing based paste rocket engine anti-reverse system, specifically including an adiabatic layer connected with a combustion chamber, an anti-reverse valve front cover, an anti-reverse valve shell, an anti-reverse plug body capable of moving forward and backward in the anti-reverse valve shell, and a gas path inlet and outlet installed on the anti-reverse valve shell. Figure 3 As shown, the technical solution at least includes the components given above, and this set of components can constitute a one-way blowing based paste rocket engine anti-reverse system, and other components can be modified according to the specific design requirements of the engine and are not included in the anti-reverse system. Among them:

[0016] The adiabatic layer connected with the engine combustion chamber is mainly responsible for isolating heat from the anti-reverse valve shell during engine operation, so it needs to use materials with low thermal conductivity and resistance to ablation, such as asbestos, ethylene-propylene-diene rubber or other heat insulation materials. When designing, attention should be paid to completely isolating the combustion chamber and accessories from the metal components such as the anti-reverse valve shell behind, and it is generally designed as a hollow cylindrical shape with steps, leaving a ring of end faces for the anti-reverse valve front cover to cooperate.

[0017] The anti-reverse valve shell forms the main structure of the anti-reverse valve, and forms a certain tolerance so that the anti-reverse valve plug body can slide therein, and the mechanism connected with the tank and the adiabatic layer is provided thereon, as well as the gas path interface. The anti-reverse valve shell does not involve heat transfer and ablation resistance, and generally uses high-strength metal structural materials such as high-strength steel, aluminum alloy, etc. The shell design mainly considers how to connect with the adiabatic layer and the combustion chamber, and needs to ensure that all metal parts do not directly contact high-temperature parts.

[0018] The front cover of the anti-flashback valve is also used to supply propellant to the engine when the engine is working, and to isolate heat from being transferred to the anti-flashback valve. Therefore, a material with low thermal conductivity, certain strength and resistance to ablation, such as high-silicon phenolic resin or other thermal insulation materials, is required. In the design, attention should be paid to completely isolating the combustion chamber and accessories from the metal components of the anti-flashback valve housing. Generally, the anti-flashback valve housing is designed as a stepped cylinder with a circle of pipeline for propellant flow in the middle, and a conical surface in the center for cooperation with the anti-flashback valve plug.

[0019] The anti-flashback valve plug closes the propellant flow channel by moving, isolates the engine gas from the propellant, and prevents the remaining burning propellant from igniting the unburned propellant in the tank along the flow channel, which may cause dangerous uncontrolled combustion or even explosion. The anti-flashback valve plug will be subjected to certain gas scouring and heat conduction, and needs to withstand high pressure and sliding. Therefore, it is recommended to use titanium alloy material with poor thermal conductivity and high strength. The plug is generally designed as a hollow cone, with a cylindrical step at the front end, and a spherical surface at the front end for sealing, cooperating with the conical surface at the rear end of the thermal insulation layer. The tail end is generally designed as a cylindrical segment for sliding guide. Attention should be paid to the gap design between the anti-flashback valve plug and the anti-flashback valve housing. Generally, a larger gap is selected for cooperation, and the gap cooperation is H / d.

[0020] In addition, the gap between the outer side of the anti-flashback valve plug and the inner side of the anti-flashback valve housing allows high-pressure gas controlling the forward and backward movement of the plug to enter the front side of the anti-flashback valve plug through the gap, and then enter the propellant supply pipeline, and finally enter the combustion chamber, forming a blowing-cooling gas flow. While blowing the remaining propellant, the entire supply pipeline is cooled to the greatest extent possible to avoid heat transfer flashback, combustion flashback and surface combustion flashback.

[0021] Among them, the blowing propellant avoids surface combustion flashback.

[0022] Because the pressure of the control gas flow is greater than the pressure of the combustion chamber, combustion flashback is avoided.

[0023] The blowing gas flow is a low-temperature high-pressure gas flow that can cool the pipeline and avoid heat transfer flashback.

[0024] The working process of the anti-flashback valve mainly includes the following steps:

[0025] (1) The upstream start propellant supply is opened, the gas outlet installed on the anti-flashback valve housing is opened, the plug blocking the flow channel is pressed by the propellant pressure surface to a pressure greater than the opening resistance given by the gas pressure behind the valve body and the friction force, and the valve body starts to move to the opening limit position, and the flow channel is gradually opened.

[0026] (2) When the plug reaches the maximum opening limit, the paste propellant flow channel is at its maximum opening, the paste propellant enters the downstream and is ignited by the ignition device, and the engine enters the stable combustion working condition.

[0027] (3) A control gas pressure greater than the propellant compression pressure is supplied to the gas inlet installed on the backfire preventer housing. Under the pressure of the control gas, the backfire preventer at its maximum opening limit begins to move towards the closing limit. Eventually, the valve body reaches the closing limit, blocking the flow channel and stopping the downward supply of propellant. Simultaneously with the valve body closing, the control gas flows into the supply line along the gap between the backfire preventer housing and the backfire preventer plug, blowing all the remaining propellant into the combustion chamber and creating a continuous purging pressure. This prevents the combustion gases from entering the backfire preventer, and the engine stops operating after the remaining propellant inside the engine has been completely burned.

[0028] The flashback arrestor plug is driven by the pressure difference between its front and rear surfaces, causing it to move back and forth within the flashback arrestor housing, thus forming a mechanical seal. The control gas pressure P required to drive the flashback arrestor plug can be calculated based on experimental experience. con Same combustion chamber pressure P c *and supply pressure P s The relationship between them is:

[0029]

[0030] The advantages of this invention are: by using the gap between the sliding plug of the anti-backfire valve and the outer shell of the anti-backfire valve as a flow channel for the purging gas, the complexity of the design of the grease rocket engine is simplified and the reliability of the design is improved. In addition, the high-speed airflow also plays the role of air cushion lubrication, which greatly accelerates the movement speed of the plug and greatly improves the valve closing response speed, thereby improving the controlled start-stop performance of the grease rocket engine.

[0031] (1) Creation point 1, by combining pneumatic purging technology and extrusion anti-backfire technology, improves the anti-backfire reliability of the anti-backfire valve of the paste rocket engine.

[0032] (2) Creation point 2: By using clearance fit as the gas flow channel for pneumatic purging, it can not only pneumatically lubricate the moving plug, but also cool the plug and propellant flow channel, avoiding heat transfer that could cause the propellant inside the engine to overheat and explode. This allows structures such as the sliding plug to use low-cost materials such as stainless steel or lightweight but not heat-resistant aluminum alloys, greatly expanding the scope of engine design. Attached Figure Description

[0033] Figure 1a This is a cross-sectional view of the engine backfire preventer valve of the present invention in the open state.

[0034] Figure 1bFigure 1 is a cross-sectional view of the engine anti-backfire valve in the closed state.

[0035] Figure 2a Figure 2 is a schematic diagram of the gas flow before the anti-backfire valve is closed.

[0036] Figure 2b Figure 3 is a schematic diagram of the gas flow after the anti-backfire valve is closed.

[0037] Figure 3 Figure 4 is a schematic diagram of the anti-backfire valve assembly.

[0038] Figure 4a Figure 5 is a cross-sectional view of the three-dimensional structure of the anti-backfire valve.

[0039] Figure 4b Figure 6 is a cross-sectional view of another three-dimensional structure of the anti-backfire valve.

[0040] The figure number is explained as follows:

[0041] 1, heat insulation layer connected with the combustion chamber; 2, anti-backfire valve door cover; 3, anti-backfire valve shell; 4, anti-backfire plug body; 5, gas inlet and outlet. DETAILED DESCRIPTION

[0042] In Figure 1a , the upstream propellant supply system is used to supply the paste propellant to the anti-backfire valve through the pipeline (in the center) of the anti-backfire valve. The propellant enters the pressure cavity in front of the valve body along the flow passage of the anti-backfire valve, at this time the supply pressure of the propellant is generally 5-8 MPa, the pressure of the pressure surface of the valve body blocking the flow passage is increased to be greater than the gas pressure (one atmosphere) in the space behind the valve body, generally reaching 0.5 MPa to start the opening process, and the valve body starts to move to the opening limit.

[0043] As the valve body reaches the maximum opening limit (as shown in Figure 1b ), the flow passage of the paste propellant rocket engine is at the maximum opening (as shown in Figure 1b ), the paste propellant enters the tubular flow passage composed of the downstream ball joint and the flexible inner liner pipe, and then enters the head of the thrust chamber after filling the flow passage. The ignition device in the thrust head is started, which is an electric heating type multiple ignition device (note that this device is not claimed as an invention, but only as a device system involved in the complete implementation of the system), the propellant is ignited after contacting the high-temperature electric heating ignition device grid, forming high-temperature gas (depending on the propellant, which can reach 1000-3000 K). The high-temperature gas makes the pressure of the thrust chamber instantaneously increase to 8-10 MPa, and the pressure returns to the upstream supply along the flow passage, so that the propellant flow rate decreases from the maximum 60 mm / s to about 10 mm / s, and the engine enters the stable working condition.

[0044] After the engine enters into stable working condition, according to the demand of the missile or boost in actual flight, here take the double pulse air-to-air missile as an example:

[0045] Generally, the rocket engine of double pulse air-to-air missile needs to provide a small thrust pulse in the early flight to make the missile enter the glide path to the target, and then needs to be shut down until the missile approaches the target, and then starts the engine again.

[0046] Therefore, in the actual flight process, after completing the first flight thrust pulse, the rocket overall control system gives the engine shutdown command, and the pilot valve system starts the supply pipeline according to the control command. The aerodynamic interface on the outer shell of the backfire prevention valve supplies high pressure gas to the valve, the high pressure gas acts on the back side of the valve, as shown in Figure 2a and Figure 2b , the valve body moves to the shutdown limit, and finally cuts off the supply of paste propellant through mechanical sealing, at the same time, the high pressure control gas enters the supply pipeline along the gap outside the valve body, and then squeezes the remaining propellant into the combustion chamber, and cools the supply pipeline. Finally, the engine is completely shut down, and the engine enters the shutdown working condition.

[0047] When the missile approaches the target, the engine starts again, the starting process is the same as the above, and will not be repeated.

[0048] And Figure 4a and Figure 4b are the structures of paste rocket engine one-way blowout backfire prevention system under two different thrust and external design adjustments. It can be seen that although the external design requirements are different, the structures of one-way blowout backfire prevention system are consistent. According to our experimental results, they all work well, which shows that this system has wide applicability and can be used in most start-stop paste rocket engine systems.

Claims

1. A one-way blow based anti-backfire system for a paste rocket engine, characterized by: The system comprises an adiabatic layer connected with the combustion chamber, a front cover of the anti-backfire valve, an outer shell of the anti-backfire valve, an anti-backfire valve plug capable of moving forward and backward in the outer shell of the anti-backfire valve, and an air path inlet and outlet installed on the outer shell of the anti-backfire valve. The upstream starting propellant supply is opened, the air path outlet installed on the outer shell of the anti-backfire valve is opened, the anti-backfire valve plug blocking the flow channel is pressed by the propellant pressure surface to a pressure greater than the opening resistance given by the gas pressure behind the valve body and the friction, the valve body starts to move to the opening limit, and the flow channel is gradually opened. The anti-backfire valve plug reaches the maximum opening limit, the propellant flow channel is at the maximum opening, the propellant enters the downstream and is ignited by the ignition device, and the engine enters the stable combustion working condition. The air path inlet installed on the outer shell of the anti-backfire valve supplies a control gas pressure greater than the propellant extrusion pressure, the anti-backfire valve at the maximum opening limit is pressed by the control gas to move to the closing limit, and finally the valve body reaches the closing limit, blocks the flow channel, and stops the propellant supply. When the valve body is closed, the control gas flows into the supply pipeline along the gap between the outer shell of the anti-backfire valve and the anti-backfire valve plug, blows all the remaining propellant into the combustion chamber, and forms a continuous blowing pressure, so that the combustion gas cannot enter the anti-backfire valve, and the engine stops working after the remaining propellant in the engine is burned out.

2. A backfire prevention system for a single -propellant paste rocket engine according to claim 1, characterized in that: The adiabatic layer connected with the combustion chamber is responsible for isolating heat transfer to the outer shell of the anti-backfire valve during engine operation, and is designed as a hollow cylindrical shape with steps, leaving a ring of end faces for the anti-backfire valve front cover to cooperate.

3. A flame-dump protection system for a single-use, ablating, propellant rocket engine according to claim 1 or 2, wherein: The adiabatic layer connected with the combustion chamber is made of a material with low thermal conductivity and resistance to ablation, including asbestos or ethylene-propylene-diene rubber.

4. The anti-backfire system for grease-based rocket engines based on unidirectional blowing according to claim 1, characterized in that: The anti-backfire valve front cover is responsible for supplying propellant to the engine during engine operation, while isolating heat transfer to the anti-backfire valve, and is designed as a cylindrical shape with steps, leaving a ring of pipelines for propellant flow in the middle, and designing a conical surface in the center to cooperate with the anti-backfire valve plug.

5. A backfire prevention system for a single -propellant, non -regenerative, paste rocket engine according to claim 1, wherein: The outer shell of the anti-backfire valve forms the main structure of the anti-backfire valve, and forms a tolerance so that the anti-backfire valve plug slides therein, and is provided with a mechanism connected with the storage tank and the adiabatic layer, and an interface connected with the air path.

6. A backfire prevention system for a single-direction blow-based paste rocket engine according to claim 1 or 5, characterized in that: The outer shell of the anti-backfire valve is made of a high-strength metal structural material, including high-strength steel or aluminum alloy.

7. A backfire prevention system for a single -propellant, non -regenerative, paste rocket engine according to claim 1, wherein: The anti-backfire valve plug closes the propellant flow channel by moving, isolates the engine gas and propellant, and prevents the remaining propellant from igniting the unburned propellant in the storage tank along the flow channel, causing dangerous uncontrolled combustion or even explosion. The anti-backfire valve plug is a hollow cone, the front end is designed as a cylindrical step, and then the front end is designed as a spherical surface for sealing, which cooperates with the conical surface at the rear end of the anti-backfire valve front cover; the tail end is designed as a cylindrical segment for sliding guide; and the gap between the anti-backfire valve plug and the outer shell of the anti-backfire valve is H / d.

8. A backfire prevention system for grease-based rocket engines based on unidirectional blowing according to claim 7, characterized in that: The gap fit is formed between the outer side of the anti-backfire valve plug and the inner side of the anti-backfire valve shell, so that the high-pressure gas controlling the forward and backward movement of the anti-backfire valve plug enters the front side of the anti-backfire valve plug through the gap, then enters the propellant supply pipeline, and finally enters the combustion chamber to form a blowing-cooling gas flow, which blows away the remaining propellant while cooling the entire supply pipeline to avoid heat transfer backfire, combustion backfire and surface combustion backfire.

9. A backfire prevention system for a single -propellant, non -regenerative, paste rocket engine according to claim 1, wherein: The anti-backfire valve plug is driven by the pressure difference between the front and back surfaces, and moves forward and backward in the anti-backfire valve shell to form a mechanical seal; the control gas pressure P required for driving the anti-backfire valve plug con The relationship between the combustion chamber pressure P c and the supply pressure P s is: 。

Images