A single-component liquid propellant rocket engine

Abstract

The present invention belongs to the technical field of rocket engines. It relates to a monopropellant liquid propellant rocket engine, which includes a combustion chamber and a thrust chamber provided at one end of the combustion chamber. A catalytic zone is provided in the combustion chamber, and a propellant distributor connected to the propellant supply system is provided at the end of the combustion chamber away from the thrust chamber. A fragmentation and evaporation zone, a saturated steam zone, and an adsorption zone are successively provided between the propellant distributor and the catalytic zone; the saturated steam zone is used for pressure stabilization to balance the change in propellant flow rate caused by the pressure fluctuation of the propellant supply system; an adsorbent and a catalyst are provided in the adsorption zone. By increasing the resistance of the propellant from atomization / evaporation to entering the catalytic region, the fluctuation of the propellant concentration entering the surface of the catalyst is reduced. In addition, the specific surface area of the catalyst is larger than that of the adsorbent. The adsorption zone is used to increase the internal diffusion resistance of the propellant on the surface of the adsorbent during the catalytic combustion process, reduce its external diffusion resistance, improve the adsorption rate, and achieve the rapid release and adsorption of the propellant.

Description

Technical Field

[0001] The present invention belongs to the technical field of rocket engines and relates to a monopropellant liquid propellant rocket engine. Background Art

[0002] A monopropellant liquid propellant is a liquid propellant that provides energy and working fluid through its own decomposition or combustion. It is stable under storage conditions, but in the presence of a heat source or catalyst, it will release a large amount of heat and gas. The monopropellant liquid propellant can be a compound containing both combustible elements and oxygen in its molecule (such as nitromethane), or a stable mixture that does not chemically react with each other at room temperature (such as hydrogen peroxide - methanol), or an endothermic compound that can release a large amount of heat and gas during decomposition (such as hydrazine). Although the energy of the monopropellant liquid propellant is relatively low, the propulsion system is simple, easy to control, suitable for pulsed operation, so it is widely used in attitude control and orbit control engines, and can also be used in gas generators.

[0003] Monopropellant engines are mostly used for satellite attitude adjustment and are rarely used in occasions with high response characteristics such as launch vehicles and missiles. However, the control process of this system is relatively easy to implement, the structure is easy to design, the production cycle is short, and the cost is low. Coupled with the rapid development of commercial space in recent years, monopropellant engines have gradually begun to be applied on launch vehicles, so they still have a certain market share in the power system.

[0004] The specific impulse of the monopropellant engine is lower than that of the bipropellant liquid engine, the response time is long and it is more sensitive to fluctuations in the propellant supply pressure during operation. The catalytic combustion under high temperature conditions is in the diffusion control stage, and the catalytic reaction rate will change violently with the change of the reactant concentration.

[0005] The monopropellant rocket engine adopts a traditional catalytic combustion mode. Since the system will withstand impacts from various aspects during operation, such as valve opening and closing, vibration of the tank diaphragm, and alternating operation of the engine, etc., which will cause the propellant concentration in the catalytic bed to change continuously, the fluctuation of the propellant is inevitable. The reaction rate of the propellant is more sensitive to the change of the reactant concentration under high temperature conditions, and its adaptability to the complex change law of the propellant supply system is poor. The fluctuation of the propellant concentration during the hot - state operation process is likely to cause the engine to explode. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to solve the problem of propellant concentration fluctuation during the catalytic combustion process of the monopropellant rocket engine, and provides a monopropellant liquid propellant rocket engine.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A single-component liquid propellant rocket engine includes a combustion chamber and a thrust chamber provided at one end of the combustion chamber. A catalytic zone is provided in the combustion chamber. A propellant distributor connected to the propellant supply system is provided at the end of the combustion chamber away from the thrust chamber. A fragmentation and evaporation zone, a saturated vapor zone, and an adsorption zone are sequentially arranged along the engine axis between the propellant distributor and the catalytic zone. Pressure stabilization is carried out through the saturated vapor zone to balance the change in propellant flow rate caused by the pressure fluctuation of the propellant supply system. An adsorbent and a catalyst are provided in the adsorption zone. The specific surface area of the catalyst is larger than that of the adsorbent. The external diffusion resistance of the propellant on the surface of the adsorbent is smaller than that of the catalyst, and the internal diffusion resistance of the propellant on the surface of the adsorbent is larger than that of the catalyst. The active sites of the adsorbent are concentrated on the outer surface to improve the adsorption and release ability of the propellant. The movement resistance of the propellant entering the combustion process on the surface of the catalyst is increased through the adsorption zone, and the concentration fluctuation of the propellant during the combustion process is reduced.

[0009] Further, a first near-adiabatic zone, a first start heating zone, a second near-adiabatic zone, a load adaptive zone, and a second start heating zone are sequentially arranged on the outer wall of the combustion chamber along the direction from the propellant distributor to the thrust chamber. A regenerative cooling pipe wound around the outer wall of the combustion chamber is provided between the load adaptive zone and the second start heating zone. One end of the regenerative cooling pipe is connected to the propellant supply system, and the other end is connected to the propellant distributor.

[0010] The first near-adiabatic zone is provided on the outer wall of the fragmentation and evaporation zone. The first start heating zone straddles the fragmentation and evaporation zone and the saturated vapor zone. The second near-adiabatic zone straddles the saturated vapor zone and the adsorption zone. The load adaptive zone is provided on the outer wall of the adsorption zone. The regenerative cooling pipe and the second start heating zone are both provided on the outer wall of the catalytic zone.

[0011] Further, the length of the first near-adiabatic zone along the engine axis accounts for 3 / 4 of the length of the fragmentation and evaporation zone, which is used to ensure that the propellant has a certain jet rigidity after entering this area and atomize the propellant into small-sized droplets.

[0012] Further, the length of the first start heating zone along the engine axis accounts for 1 / 4 of the remaining length of the fragmentation and evaporation zone and 1 / 2 of the length of the saturated vapor zone.

[0013] Further, the length of the second near-adiabatic zone along the engine axis accounts for 1 / 2 of the remaining length of the saturated vapor zone and 1 / 2 of the length of the adsorption zone.

[0014] Further, the length of the load adaptive zone along the engine axis accounts for the remaining 1 / 2 of the length of the adsorption zone.

[0015] Furthermore, several heat dissipation ribs are provided on the outer wall of the combustion chamber within the load adaptive region to block the heat that cannot be exchanged through regenerative cooling during the combustion process in the catalytic region under high load conditions; the surface of the heat dissipation ribs is covered with a SiC coating, and the roughness range is 10 μm to 200 μm. The load adaptive region has a good heat dissipation level under high temperature conditions, blocking excessive heat during the catalytic bed combustion process. When the thrust is increased, regenerative cooling cannot effectively discharge the heat transferred from the catalytic region. At this time, heat dissipation is carried out through the heat dissipation ribs to block the heat; after the engine shuts down, it effectively ensures that excessive heat after engine shutdown is transferred to the upstream adsorption region, ensuring that the adsorption region can completely adsorb the propellant molecules in the dispenser and the saturated vapor region, and ensuring that the propellant does not condense in the engine after shutdown.

[0016] Furthermore, the particle size of the catalyst particles is larger than that of the adsorbent particles, and the clearance in the catalytic region is larger than that in the adsorption region.

[0017] Furthermore, the catalyst used is a catalyst with a surface pore diameter concentrated in the range of 45 to 55 nm.

[0018] Furthermore, the specific surface area of the adsorbent is controlled to be 50 to 100 m 2 / g. By ensuring the average pore size distribution of the adsorbent is controlled above 50 nm during the preparation process, it has a certain adsorption surface and relatively small surface adsorption resistance; at the same time, a metal oxide material with a high thermal conductivity is used as the adsorbent carrier. A metal oxide with a relatively high thermal conductivity such as γ-Al2O3 can be used as the adsorbent carrier, and low thermal conductivity materials such as cordierite and silica are avoided.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. The present invention solves the problem of fluctuations in propellant supply under high temperature conditions, improves the utilization rate of the catalyst, and enhances the adaptability of the monopropellant engine to complex environments. By adopting a saturated vapor region, a catalyst with a small pore diameter and a high specific surface area, and increasing the adsorption region, the fluctuations in the propellant flow rate on the catalyst surface are suppressed to a certain extent, avoiding the explosion of the engine caused by fluctuations in the propellant flow rate during the diffusion-controlled combustion process at high temperature.

[0021] 2. The present invention shortens the response time of the engine. By setting an adsorption region, the combustion start-stop process is accelerated. The adsorption region can capture the propellant inside the combustion chamber after the engine shuts down, and the engine output thrust will not show a tailing phenomenon; when the engine shuts down and starts again, with the cooperation of the start heating region, the concentration of the propellant in the initial ignition stage is increased, and thus the start response characteristics of the engine under cold conditions are improved.

[0022] 3. By optimizing the structure of the monopropellant engine, the present invention enhances the heat dissipation during the adsorption process, further improving the adsorption efficiency in the adsorption zone while reducing the volume of the catalytic zone. The adsorption zone is used to regulate the internal and external diffusion resistance characteristics of the catalytic combustion process, ensuring a significant improvement in the cold and hot start response characteristics of the engine. Additionally, by adding a saturated vapor zone for pressure stabilization, the variation in the propellant flow rate caused by the pressure fluctuation in the propellant supply system is balanced, fundamentally ensuring the stability of the engine's output thrust and the consistency of the reaction rate. This monopropellant engine has good adaptability to system shocks, higher working safety under high-temperature conditions, and good economic efficiency and reliability.

[0023] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be learned from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. Brief Description of the Drawings

[0024] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0025] Figure 1 It is a schematic diagram of the monopropellant liquid propellant rocket engine in the present invention.

[0026] Reference Numerals: 1 - Propellant Supply System; 2 - Solenoid Valve; 3 - Propellant Distributor; 4 - Crushing and Evaporation Zone; 5 - Saturated Vapor Zone; 6 - Adsorption Zone; 7 - Catalytic Zone; 8 - Thrust Chamber; 9 - First Near-Adiabatic Zone; 10 - First Start Heating Zone; 11 - Second Near-Adiabatic Zone; 12 - Load Adaptive Zone; 13 - Regenerative Cooling Pipe; 14 - Second Start Heating Zone. Detailed Embodiments

[0027] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention schematically, and the following embodiments and the features in the embodiments can be combined with each other without conflict.

[0028] Among them, the attached drawings are only for illustrative purposes, showing only schematic diagrams rather than actual diagrams, and should not be construed as a limitation on the present invention; in order to better illustrate the embodiments of the present invention, some components in the attached drawings will be omitted, enlarged or reduced, which does not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the attached drawings may be omitted.

[0029] In the attached drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the attached drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the attached drawings are only for illustrative purposes and should not be construed as a limitation on the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0030] Please refer to Figure 1 , which is a single-component liquid propellant rocket engine, including a combustion chamber and a thrust chamber 8 provided at one end of the combustion chamber. A catalytic zone 7 is provided in the combustion chamber. A propellant distributor 3 connected to the propellant supply system 1 is installed at the end of the combustion chamber away from the thrust chamber 8. Along the propellant distributor 3 towards the thrust chamber 8 on the outer wall of the combustion chamber, a first near-adiabatic zone 9, a first start heating zone 10, a second near-adiabatic zone 11, a load adaptive zone 12, and a second start heating zone 14 are sequentially arranged; a regenerative cooling pipe 13 wound around the outer wall of the combustion chamber is installed between the load adaptive zone 12 and the second start heating zone 14; one end of the regenerative cooling pipe 13 is connected to the propellant supply system 1 through a solenoid valve 2, and the other end is connected to the propellant distributor 3.

[0031] A fragmentation evaporation zone 4, a saturated steam zone 5, and an adsorption zone 6 are sequentially arranged along the engine axis between the propellant distributor 3 and the catalytic zone 7; pressure stabilization is carried out through the saturated steam zone 5 to balance the change in propellant flow rate caused by the pressure fluctuation of the propellant supply system 1; an adsorbent and a catalyst are provided in the adsorption zone 6. The specific surface area of the catalyst is larger than that of the adsorbent. The external diffusion resistance of the propellant on the surface of the adsorbent is smaller than that of the catalyst, and the internal diffusion resistance of the propellant on the surface of the adsorbent is larger than that of the catalyst. The active sites of the adsorbent are mostly concentrated on the outer surface to improve the adsorption and release ability of the propellant; the movement resistance of the propellant entering the combustion process on the surface of the catalyst is increased through the adsorption zone 6, and the concentration fluctuation of the propellant during the combustion process is reduced.

[0032] The first near-adiabatic zone 9 is installed on the outer wall of the fragmentation evaporation zone 4. The first startup heating zone 10 is arranged across the fragmentation evaporation zone 4 and the saturated steam zone 5. The second near-adiabatic zone 11 is arranged across the saturated steam zone 5 and the adsorption zone 6. The load adaptive zone 12 is installed on the outer wall of the adsorption zone 6. The regeneration cooling pipe 13 and the second startup heating zone 14 are both installed on the outer wall of the catalytic zone 7. Among them, the length of the first near-adiabatic zone 9 along the engine axis accounts for 3 / 4 of the length of the fragmentation evaporation zone 4, which is used to ensure that the propellant has a certain jet rigidity after entering this area and atomizes the propellant into small-sized droplets. The length of the first startup heating zone 10 along the engine axis accounts for 1 / 4 of the remaining length of the fragmentation evaporation zone 4 and 1 / 2 of the length of the saturated steam zone 5. The length of the second near-adiabatic zone 11 along the engine axis accounts for 1 / 2 of the remaining length of the saturated steam zone 5 and 1 / 2 of the length of the adsorption zone 6. The length of the load adaptive zone 12 along the engine axis accounts for the remaining 1 / 2 of the length of the adsorption zone 6.

[0033] On the outer wall of the combustion chamber in the load adaptive zone 12, there are multiple heat dissipation ribs, which block the heat that cannot be exchanged during the regeneration cooling of the combustion process in the catalytic zone 7 under large load conditions; the surface of the heat dissipation ribs is covered with a SiC coating, and the roughness range is 10μm - 200μm. The load adaptive zone 12 has a good heat dissipation level under high temperature conditions, blocking the excessive heat in the catalytic bed combustion process. When the thrust is increased, the regeneration cooling cannot effectively discharge the heat transferred from the catalytic zone 7. At this time, heat dissipation is carried out through the heat dissipation ribs to block the heat; after the engine shuts down, it effectively ensures that the excessive heat after engine shutdown is transferred to the upstream adsorption zone 6, ensuring that the adsorption zone 6 can completely adsorb the propellant molecules in the propellant dispenser 3 and the saturated steam zone 5, and ensuring that the propellant does not condense in the engine after shutdown.

[0034] The particle size of the catalyst is larger than that of the adsorbent particle, and the clearance in the catalytic zone 7 is larger than that in the adsorption zone 6. The catalyst uses a catalyst with a surface pore diameter concentratedly distributed between 45 - 55nm. Among them, the specific surface area of the adsorbent is controlled between 50 - 100m 2 / g. By controlling the preparation process, the average pore diameter distribution of the adsorbent is controlled near 50nm, so that it has a certain adsorption surface and a small surface adsorption resistance; at the same time, a metal oxide material with a high thermal conductivity is used as the adsorbent carrier. A metal oxide with a relatively high thermal conductivity such as γ-Al2O3 can be used as the adsorbent carrier, and low thermal conductivity materials such as cordierite and silica are avoided.

[0035] When the rocket engine in the present invention operates, the liquid propellant enters the regenerative cooling channel and then flows into the propellant distributor 3. The propellant droplets are broken and atomized in the propellant distributor 3, and while flowing along the engine axis direction, they continuously absorb heat from the saturated vapor zone 5 or the heat input from the startup heating, thereby ensuring that the droplets are completely evaporated after leaving the fragmentation and evaporation zone 4; the vapor then enters the adsorption zone 6, where the outer wall surface of this area is an adiabatic process, and the heat released after the propellant is adsorbed on the adsorbent surface is continuously transferred to the upstream saturated vapor zone 5 to ensure the energy required for droplet evaporation; downstream of the adsorption zone 6, the outer wall surface of the combustion chamber is the load adaptive zone 12. As the adsorption process progresses and the combustion area proceeds, a large amount of heat enters this area, and by controlling the wall temperature level, a certain adsorption amount of the adsorbed propellant molecules can be ensured in the adsorption zone 6; after the propellant enters the catalytic zone 7, a violent chemical reaction occurs, and the generated high-temperature and high-pressure gas flow enters the thrust chamber 8 and then forms thrust. The startup heating zone is turned on in advance under cold startup or low load conditions and stops heating after the temperature level of the engine combustion chamber is established.

[0036] When the engine is restarted, during the process of the propellant flowing through the adsorption zone 6, since a large number of propellant molecules are stored in the adsorption zone 6 after shutdown, the initial concentration of the propellant is relatively high, and the propellant can quickly penetrate the adsorption zone 6 and then enter the catalytic zone 7 for reaction, greatly shortening the startup time of the engine; when the engine shuts down, the wall of the load adaptive zone 12 dissipates heat strongly, quickly cooling the upstream adsorption zone 6 and the downstream catalytic zone 7 of the combustion chamber, and the catalytic combustion area will quickly shrink, effectively controlling the combustion process.

[0037] When the engine increases the load, the function of the catalytic zone 7 cannot meet the output demand. As the reaction heat continuously transfers to the upstream area, the adsorption efficiency of the adsorbent in the adsorption zone 6 is affected after the temperature rises. The heat dissipation through the heat dissipation ribs in the load adaptive zone 12 makes up for the deficiency of the regenerative cooling heat exchange capacity, ensuring that the engine has a certain load adjustment ability and can operate safely.

[0038] Under the condition of extreme thrust demand, the first startup heating zone 10 and the second startup heating zone 14 can be turned on for heating to ensure the temperature demand for small thrust.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A single-component liquid propellant rocket engine, comprising a combustion chamber and a thrust chamber provided at one end of the combustion chamber, wherein a catalytic zone is provided in the combustion chamber, and it is characterized in that: At one end of the combustion chamber far from the thrust chamber, there is a propellant distributor connected to the propellant supply system. Between the propellant distributor and the catalytic zone, there are a fragmentation and evaporation zone, a saturated vapor zone, and an adsorption zone arranged in sequence along the engine axis. The saturated vapor zone is used for pressure stabilization to balance the change in propellant flow rate caused by the pressure fluctuation of the propellant supply system. In the adsorption zone, there are adsorbents and catalysts. The specific surface area of the catalyst is larger than that of the adsorbent. The external diffusion resistance of the propellant on the surface of the adsorbent is smaller than that of the catalyst, and the internal diffusion resistance of the propellant on the surface of the adsorbent is larger than that of the catalyst. The active sites of the adsorbent are concentrated on the outer surface to improve the adsorption and release ability of the propellant. By means of the adsorption zone, the movement resistance of the propellant entering the combustion process on the surface of the catalyst is increased, and the concentration fluctuation of the propellant during the combustion process is reduced.

2. The monopropellant liquid propellant rocket engine according to claim 1, characterized in that: On the outer wall of the combustion chamber, there are a first near-adiabatic zone, a first start-up heating zone, a second near-adiabatic zone, a load self-adaptive zone, and a second start-up heating zone arranged in sequence from the propellant distributor towards the thrust chamber. Between the load self-adaptive zone and the second start-up heating zone, there is a regenerative cooling pipe wound around the outer wall of the combustion chamber. One end of the regenerative cooling pipe is connected to the propellant supply system, and the other end is connected to the propellant distributor. The first near-adiabatic zone is arranged on the outer wall of the fragmentation and evaporation zone. The first start-up heating zone straddles the fragmentation and evaporation zone and the saturated vapor zone. The second near-adiabatic zone straddles the saturated vapor zone and the adsorption zone. The load self-adaptive zone is arranged on the outer wall of the adsorption zone. Both the regenerative cooling pipe and the second start-up heating zone are arranged on the outer wall of the catalytic zone.

3. The single-component liquid propellant rocket engine according to claim 2, characterized in that: The length of the first near-adiabatic zone along the engine axis accounts for 3 / 4 of the length of the fragmentation and evaporation zone, which is used to ensure that the propellant has a certain jet rigidity after entering this zone and atomize the propellant into small-sized droplets.

4. The monopropellant liquid propellant rocket engine according to claim 3, characterized in that: The length of the first start-up heating zone along the engine axis accounts for 1 / 4 of the remaining length of the fragmentation and evaporation zone and 1 / 2 of the length of the saturated vapor zone.

5. The monopropellant liquid propellant rocket engine according to claim 4, characterized in that: The length of the second near-adiabatic zone along the engine axis accounts for 1 / 2 of the remaining length of the saturated vapor zone and 1 / 2 of the length of the adsorption zone.

6. The single-component liquid propellant rocket engine according to claim 5, characterized in that: The length of the load self-adaptive zone along the engine axis accounts for the remaining 1 / 2 of the length of the adsorption zone.

7. The monopropellant liquid propellant rocket engine according to claim 2, characterized in that: On the outer wall of the combustion chamber in the load self-adaptive zone, there are several heat dissipation ribs, which are used to block the heat that cannot be exchanged by regenerative cooling during the combustion process in the catalytic zone under high load conditions. The surface of the heat dissipation ribs is covered with a SiC coating, and the roughness range is 10μm - 200μm.

8. The monopropellant liquid propellant rocket engine according to claim 1, characterized in that: The particle size of the catalyst is larger than that of the adsorbent, and the clearance in the catalytic zone is larger than that in the adsorption zone.

9. The single-component liquid propellant rocket engine according to claim 1, characterized in that: The catalyst used is a catalyst with the surface pore diameter concentratedly distributed between 45 and 55nm.

10. The single-component liquid propellant rocket engine according to claim 1, characterized in that: The specific surface area of the adsorbent is controlled to be 50-100 m 2 / g. By ensuring that the average pore size distribution of the adsorbent is controlled above 50 nm during the preparation process, it has a certain adsorption surface and a relatively small surface adsorption resistance; at the same time, a metal oxide material with a high thermal conductivity is used as the adsorbent carrier.

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