A thermoelectric hybrid rocket engine

Abstract

The present invention belongs to the field of aerospace propulsion technology, and specifically relates to a thermoelectric hybrid rocket engine, including a pressurizing device, an oxidizer storage tank and an engine. The pressurizing device provides high-pressure gas to the oxidizer storage tank, thereby pressurizing the inner cavity of the oxidizer storage tank, so that the pressure in the oxidizer storage tank is maintained at a preset value, and the liquid oxidizer in the oxidizer storage tank is heated to a saturation temperature under a preset pressure by an electric heating device. When the engine is started, the liquid oxidizer in the oxidizer storage tank is transported to a water supply pipeline, and the high-temperature oxidizer is then input into a combustion chamber through the water supply pipeline, and a combustion reaction is carried out together with the fuel, and the high-temperature and high-pressure gas is ejected from the tail nozzle to provide thrust. When the high-temperature gaseous oxidizer participates in combustion, the heat energy inside it will be released, so that the combustion process of the engine can release more energy and improve the specific impulse of the engine.

Description

Technical Field

[0001] The invention belongs to the field of aerospace propulsion technology, and in particular relates to a thermoelectric hybrid rocket engine. Background Art

[0002] Solid rocket engines are mainly composed of solid propellant, combustion chamber shell, nozzle and ignition device. They have the advantages of simple structure, good long-term storage, strong reliability and simple operation and maintenance. They are widely used in various missiles, spacecraft and launch vehicles. The propellant grain is made of a uniform mixture of oxidizer and fuel. Some energetic materials are often added to increase the specific impulse of the engine. These energetic materials are highly sensitive and pose a risk of being flammable and explosive.

[0003] For solid-liquid hybrid engines, since solid fuel and liquid oxidizer are stored in the combustion chamber and oxidizer tank respectively, the engine thrust can be adjusted by changing the opening of the oxidizer flow regulating valve. However, the oxidizer needs to be stored in an additional tank, which increases the structural mass of the engine and causes a decrease in the overall performance of the engine. How to improve the specific impulse of the solid-liquid hybrid engine has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] The purpose of the present invention is to provide a thermoelectric hybrid rocket engine to solve the problems existing in the above-mentioned prior art. The inner cavity of the oxidizer storage tank is pressurized by a pressurizing device to maintain the pressure in the oxidizer tank at a preset value, the liquid oxidizer is heated to the saturation temperature by an electric heating device, and the high-temperature oxidizer is input into the combustion chamber to undergo a combustion reaction together with the fuel. The heat energy inside the high-temperature oxidizer will be released, so that the combustion process of the engine can release more energy and improve the engine specific impulse.

[0005] A thermoelectric hybrid rocket engine, comprising a pressurizing device, an oxidizer storage tank and an engine; the pressurizing device is connected to the oxidizer storage tank; an electric heating device is arranged in the oxidizer storage tank; the engine comprises an engine casing and a tail nozzle, a fuel tank and a combustion chamber are arranged inside the engine casing, the tail nozzle is installed at the bottom of the engine casing and communicated with the combustion chamber; the oxidizer storage tank is communicated with the combustion chamber through a water supply pipeline;

[0006] Liquid oxidant is stored in the oxidant tank, and high-pressure gas is injected into the oxidant tank through a pressurizing device until the pressure in the oxidant tank reaches a preset value. At the same time, the electric heating device in the oxidant tank is controlled to work so that the liquid oxidant is heated to the saturation temperature under the preset pressure. When the engine is started, the saturated liquid oxidant is passed into a water supply pipeline with a lower pressure. The liquid oxidant will release pressure and expand in the water supply pipeline to form a high-temperature gaseous oxidant. The high-temperature gaseous oxidant enters the combustion chamber of the engine, and after a combustion reaction with the fuel, the high-temperature and high-pressure combustion gas is ejected from the tail nozzle to provide thrust.

[0007] Furthermore, the pressurizing equipment adopts a high-pressure gas cylinder, in which high-pressure inert gas is stored, and the high-pressure gas cylinder is connected to the oxidant storage tank through a gas supply pipeline.

[0008] Furthermore, a pressure reducing valve and a gas supply valve are arranged on the gas supply pipeline between the high-pressure gas cylinder and the oxidant storage tank, the pressure reducing valve is arranged close to the high-pressure gas cylinder, and the gas supply valve is arranged on the side of the pressure reducing valve away from the high-pressure gas cylinder; the gas in the high-pressure gas cylinder passes through the pressure reducing valve (after being reduced in pressure), and then the timing of filling into the oxidant storage tank is controlled by the gas supply valve.

[0009] Furthermore, an oxidant nozzle is installed at the end of the water supply pipeline extending into the combustion chamber, and the oxidant nozzle adopts a hydraulic centrifugal atomizing nozzle.

[0010] Furthermore, the water supply pipelines are divided into multiple groups and are evenly arranged on the outer periphery of the engine casing. The oxidant nozzles are evenly arranged along the circumference of the combustion chamber side wall. Each group of water supply pipelines is provided with a water supply valve. The water supply valve is used to control the flow rate and flow velocity of the oxidant. The opening size of the water supply valve can determine the amount of oxidant supplied to the combustion chamber. The thrust of the engine is changed by controlling the oxygen-fuel ratio in the combustion chamber, thereby achieving adjustable thrust of the engine.

[0011] Furthermore, an air inlet is provided at the top of the oxidant storage tank, which is connected to the pressurizer. The equipment has multiple groups of water outlets along the circumference of the bottom, and each group of water outlets is correspondingly connected to a group of water supply pipelines.

[0012] Furthermore, the interior of the oxidant storage tank is divided into a heating zone and a drainage zone, the heating zone is close to the air inlet, and the drainage zone is close to the water outlet; the electric heating device includes a U-shaped electric heating rod, which is installed in the heating zone inside the oxidant storage tank and is evenly arranged along the circumference of the inner wall of the heating zone.

[0013] Furthermore, an engine insulation layer is laid inside the engine casing to isolate the engine casing from high-temperature fuel gas, thereby extending the service life of the engine; an oxidizer storage tank is laid inside the oxidizer storage tank with an oxidizer storage tank insulation layer, which completely wraps the inner wall of the oxidizer storage tank to slow down the heat transfer of saturated liquid oxidizer in the oxidizer storage tank and reduce energy loss.

[0014] Furthermore, the fuel tank contains metal fuel, which is freely loaded in the form of powder or placed in the fuel tank in the form of powder; an elastic pad is filled between the fuel tank and the inner wall of the engine casing to protect the fuel tank from damage due to impact.

[0015] Furthermore, the tail nozzle adopts a convergent-divergent nozzle, and the expansion of the high-temperature and high-pressure combustion gas through the convergent-divergent nozzle increases its flow velocity.

[0016] The beneficial effects of the present invention are:

[0017] The present invention provides high-pressure gas to the oxidant storage tank through a pressurizing device, thereby pressurizing the inner cavity of the oxidant storage tank, maintaining the pressure in the oxidant tank at a preset value, and heating the liquid oxidant in the oxidant storage tank to a saturation temperature under a preset pressure through an electric heating device. When the engine is started, the liquid oxidant in the oxidant storage tank is transported to a water supply pipeline, and the high-temperature oxidant is then input into the combustion chamber through the water supply pipeline, and a combustion reaction is carried out together with the fuel, and the high-temperature and high-pressure gas is ejected from the tail nozzle to provide thrust. When the high-temperature gaseous oxidant participates in combustion, the heat energy inside it will be released, so that the combustion process of the engine can release more energy and improve the engine specific impulse. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the overall structure of a thermoelectric hybrid rocket engine.

[0019] Figure 2 A schematic cross-sectional view of an oxidant storage tank.

[0020] Figure 3 A cross-sectional diagram of the engine.

[0021] Among them, 1. high-pressure gas cylinder; 2. vent; 3. pressure reducing valve; 4. air supply valve; 5. oxidizer storage tank; 51. air inlet; 52. oxidizer storage tank shell; 53. oxidizer storage tank insulation layer; 54. U-shaped electric heating rod; 55. water outlet; 6. water supply valve; 7. water supply pipeline; 8. engine; 81. engine shell; 82. engine insulation layer; 83. oxidizer nozzle; 84. combustion chamber; 85. tail nozzle; 86. elastic pad; 87. fuel storage tank. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings.

[0023] like Figures 1 to 3 As shown, in this embodiment, a thermoelectric hybrid rocket engine is provided, including an engine 8, an oxidizer storage tank 5 and a pressurizing device. The pressurizing device can provide high-pressure gas to the oxidizer storage tank 5, thereby pressurizing the oxidizer storage tank 5 to maintain the oxidizer in the oxidizer tank at a preset pressure. An electric heating device is provided in the oxidizer storage tank 5, and the liquid oxidizer in the oxidizer storage tank 5 is heated to a saturation temperature under a preset pressure by the electric heating device to maintain the liquid oxidizer in a saturated state. The oxidizer storage tank 5 is connected to the combustion chamber 84 of the engine 8 through a water supply pipeline 7, and a water supply valve 6 is provided on the water supply pipeline 7.

[0024] Working principle: a certain amount of liquid oxidant is stored in the oxidant storage tank 5, and high-pressure gas is injected into the oxidant storage tank 5 through a pressurizing device until the pressure in the oxidant storage tank 5 reaches a preset value. At the same time, the electric heating device in the oxidant storage tank 5 is controlled to work so that the liquid oxidant is heated to the saturation temperature under the preset pressure, and the liquid oxidant has a large thermal energy. When the engine 8 is started, the liquid oxidant in the oxidant storage tank 5 is transported to the water supply pipeline 7. Since the water supply pipeline 7 is directly connected to the combustion chamber 84, the pressure in the water supply pipeline 7 is relatively low. When the saturated liquid oxidant is introduced into the water supply pipeline 7, the liquid oxidant will be depressurized and expanded in the water supply pipeline 7 to form a high-temperature gaseous oxidant. The high-temperature gaseous oxidant is then input into the combustion chamber 84 through the water supply pipeline 7 and undergoes a combustion reaction together with the fuel. Since the combustion reaction is a process of releasing energy, when the high-temperature gaseous oxidant participates in the combustion, the heat energy inside it will be released, so that the combustion process of the engine 8 can release more energy and improve the engine specific impulse.

[0025] In one embodiment, the pressurizing device is a high-pressure gas cylinder 1. The preferred preset pressure value in the high-pressure gas cylinder 1 is between 3-5MPa. The preset pressure value can be adjusted according to the strength of the high-pressure gas cylinder 1 itself. The high-pressure gas cylinder 1 is preferably a cylindrical pressure storage tank. The high-pressure gas in the high-pressure gas cylinder 1 is preferably a high-pressure inert gas. One end of the high-pressure gas cylinder 1 is a vent 2, and the high-pressure gas cylinder 1 is connected to the oxidant storage tank 5 through the vent 2.

[0026] In one embodiment, a gas supply pipeline is connected between the high-pressure gas cylinder 1 and the oxidant storage tank 5, and a pressure reducing valve 3 and a gas supply valve 4 are sequentially arranged on the gas supply pipeline. The pressure reducing valve 3 is arranged close to the high-pressure gas cylinder 1, and the gas supply valve 4 is arranged on the side of the pressure reducing valve 3 away from the high-pressure gas cylinder 1. After the gas in the high-pressure gas cylinder 1 is reduced in pressure by the pressure reducing valve 3, the gas supply valve 4 controls the timing of filling into the oxidant storage tank 5, which can not only reduce the pressure on the oxidant storage tank 5 after being filled with gas, but also control the timing of gas supply. In actual use, the pressure in the oxidant storage tank 5 is detected in real time. When the pressure is lower than the preset value, the opening of the gas supply valve 4 is increased, so as to timely inject enough inert gas into the oxidant storage tank 5. When the pressure is higher, the same is true, that is, "control of gas supply timing" is realized.

[0027] In one embodiment, the engine 8 includes an engine housing 81, in which a fuel tank 87 and a combustion chamber 84 are arranged, and the fuel tank 87 and the combustion chamber 84 are sequentially connected from top to bottom in the engine housing 81, and a tail nozzle 85 is provided at the bottom of the engine housing 81, and the tail nozzle 85 is connected to the combustion chamber 84. Generally speaking, the high-pressure gas cylinder 1, the fuel tank 87, the combustion chamber 84 and the tail nozzle 85 are arranged sequentially from top to bottom. Preferably, an engine insulation layer 82 is laid inside the engine housing 81, and the engine insulation layer 82 is preferably ablation-resistant rubber, and the engine housing 81 is isolated from high-temperature fuel gas by the engine insulation layer 82, thereby extending the service life of the engine 8.

[0028] The oxidant tank 5 includes an oxidant tank shell 52, and an oxidant tank insulation layer 53 is also laid inside the oxidant tank shell 52. The oxidant tank insulation layer 53 will be able to completely wrap the inner wall of the oxidant tank 5, thereby ensuring that it has a good high-temperature insulation effect. The oxidant tank insulation layer 53 slows down the heat transfer of saturated water in the oxidant tank 5, and reduces energy loss to a certain extent. Metal fuel is stored inside the fuel tank 87, and the oxidant is water. The metal fuel not only has a high volume energy density, but also has low cost and is easy to obtain. Using metal as fuel and water as oxidant can effectively save costs. The metal fuel can be freely loaded in the form of a charge or placed in the fuel tank 87 in a powder form. The metal fuel is preferably magnesium powder, aluminum powder or magnesium-aluminum alloy powder.

[0029] The tail nozzle 85 is a convergent-divergent nozzle, which is located at the end of the metal fuel engine 8 and is connected to the combustion chamber 84 shell by welding. The throat part of the tail nozzle 85 is made of ablation-resistant graphite. The high-temperature and high-pressure combustion gas generated when the engine 8 is working increases its flow speed through the expansion of the convergent-divergent nozzle, and the high-temperature and high-pressure combustion gas provides reverse thrust when it is ejected from the tail nozzle 85.

[0030] In one embodiment, an elastic pad 86 is filled between the fuel tank 87 and the inner wall of the engine housing 81. Preferably, the elastic pad 86 fills the top of the metal fuel engine, and the elastic pad 86 is close to the fuel tank 87, so that the fuel tank 87 is effectively protected by the elastic pad 86 to prevent the fuel from being damaged by impact.

[0031] In one embodiment, an oxidant nozzle 83 is further included, through which the oxidant is sprayed into the combustion chamber 84. When the oxidant is water, the oxidant nozzle 83 is also called a water inlet nozzle. The oxidant nozzle 83 is fixed on the inner wall of the combustion chamber 84, and the oxidant nozzle 83 is connected to the water supply pipeline 7. Preferably, the oxidant nozzle 83 is threadedly connected to the water supply pipeline 7. The oxidant nozzle 83 is provided with a plurality of oxidant nozzles, and the oxidant nozzles 83 are evenly arranged along the circumference of the side wall of the combustion chamber 84. The oxidant nozzle 83 is a hydraulic centrifugal atomizing nozzle. The oxidant nozzle 83 has a simple structure, and atomization can be completed only by relying on the incoming water pressure. The spray cone angle can reach 60°-120°, and the atomized water droplets can fully contact with the molten metal fuel to improve the combustion efficiency.

[0032] In one embodiment, there are multiple groups of water supply pipelines 7, and the water supply pipelines 7 and the corresponding water supply valves 6 are evenly arranged on the periphery of the engine housing 81. The water supply pipelines 7 are fixedly connected to the oxidant nozzles 83. The oxidant can be stably transported to the water inlet nozzles on the inner wall of the combustion chamber 84 through the water supply pipelines 7, and the flow rate and flow velocity of the oxidant can be controlled by the water supply valves 6. Whether the oxidant needs to be introduced into the combustion chamber 84 can be controlled by switching the water supply valves 6. If the oxidant is stopped, it means that the engine 8 is shut down and stopped working. The opening size of the water supply valves 6 can determine the amount of oxidant supplied to the combustion chamber 84, that is, by controlling the size of the oxygen-fuel ratio in the combustion chamber 84 and thus changing the thrust size of the engine 8, the engine 8 can be turned on and off and the thrust adjustability can be achieved.

[0033] In one embodiment, the electric heating device includes a U-shaped electric heating rod 54, which is laid on the inner wall of the oxidant storage tank 5, and the U-shaped electric heating rod 54 is placed near the side wall of the oxidant storage tank 5. Preferably, the U-shaped electric heating rod 54 is evenly arranged along the circumference of the oxidant storage tank 5. When in use, the U-shaped electric heating rod, as an important component of the oxidant storage tank 5, uses electric energy to heat the water in the oxidant storage tank 5 to a saturated state under the design pressure, that is, the highest temperature of the water under the pressure. After the inert gas in the high-pressure gas cylinder 1 is filled into the gas cylinder, the water supply pressure is guaranteed to be constant, and a stable flow of oxidant can be provided to the combustion chamber 84.

[0034] In this embodiment, an air inlet 51 and a water outlet 55 are respectively provided at both ends of the oxidant storage tank 5, the air inlet 51 is located at the top of the oxidant storage tank 5, the water outlet 55 is located at the bottom of the oxidant storage tank 5, the air inlet 51 is connected to the pressurizing device, the water supply valve 6 is arranged near the water outlet 55, and a thread is provided at the extension portion of the water outlet 55, and the water outlet 55 is threadedly connected to the water supply valve 6. The water outlets 55 are evenly arranged along the circumference of the bottom of the oxidant storage tank 5, and each water outlet 55 is connected to a corresponding water supply valve 6 and a water inlet pipeline.

[0035] In one embodiment, the oxidant storage tank 5 is divided into a heating area and a drainage area from one end of the air inlet 51 to one end of the water outlet 55, the heating area is close to the air inlet 51, the drainage area is close to the water outlet 55, and the electric heating device is located in the heating area. While ensuring that the electric heating device can meet the preset heating power, the overall volume of the electric heating device can be reduced, the space occupied by the electric heating device can be reduced, and the electric heating device is prevented from occupying too much space in the oxidant storage tank 5, and the vibration generated by the electric heating device when the engine 8 is working is reduced, thereby improving the overall stability.

[0036] The engine 8 of the present invention uses high-energy-density metal aluminum and metal magnesium as engine fuel, and uses water as oxidant. These materials are easy to obtain and inexpensive, which significantly reduces the manufacturing and use costs of the engine 8. At the same time, since the oxidant storage tank 5 of the engine 8 is separated from the fuel storage tank 87, the oxidant is provided to the combustion chamber 84 through the water supply pipeline 7 and the water supply valve 6. The valve switch of the water supply valve 6 can realize the shutdown and start of the engine 8 at any time, and the oxidant supply amount is adjusted by adjusting the valve opening, thereby adjusting the engine performance and achieving the purpose of adjustable engine thrust. At the same time, an electric heating device is used to heat the oxidant, which further increases the oxidant energy, so that the engine combustion process releases more heat, thereby improving the engine specific impulse.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A thermoelectric hybrid rocket engine, characterized in that: The invention comprises a pressurizing device, an oxidant storage tank (5) and an engine (8); the pressurizing device is connected to the oxidant storage tank (5); an electric heating device is arranged inside the oxidant storage tank (5); the engine (8) comprises an engine casing (81) and a tail nozzle (85); a fuel tank (87) and a combustion chamber (84) are arranged inside the engine casing (81); the tail nozzle (85) is installed at the bottom of the engine casing (81) and is in communication with the combustion chamber (84); the oxidant storage tank (5) is in communication with the combustion chamber (84) via a water supply pipeline (7); A liquid oxidant is stored in the oxidant storage tank (5), and a high-pressure gas is injected into the oxidant storage tank (5) through a pressurizing device until the pressure in the oxidant storage tank (5) reaches a preset value. At the same time, the electric heating device in the oxidant storage tank (5) is controlled to work so that the liquid oxidant is heated to a saturation temperature under a preset pressure. When the engine (8) is started, the saturated liquid oxidant is introduced into the water supply pipeline (7) with a lower pressure. The liquid oxidant will expand in the water supply pipeline (7) due to pressure relief to form a high-temperature gaseous oxidant. The high-temperature gaseous oxidant enters the combustion chamber (84) of the engine (8), and after a combustion reaction with the fuel, the high-temperature and high-pressure combustion gas is ejected from the tail nozzle (85) to provide thrust. An oxidant nozzle (83) is installed at the end of the water supply pipeline (7) extending into the combustion chamber (84), and the oxidant nozzle (83) is a hydraulic centrifugal atomizing nozzle; The water supply pipelines (7) are multiple groups, which are evenly arranged on the outer periphery of the engine housing (81); the oxidant nozzles (83) are evenly arranged along the circumference of the side wall of the combustion chamber (84); each group of water supply pipelines (7) is provided with a water supply valve (6); the flow rate and flow velocity of the oxidant are controlled by the water supply valve (6); the opening size of the water supply valve (6) can determine the amount of oxidant supplied to the combustion chamber (84); the thrust of the engine (8) is changed by controlling the oxygen-fuel ratio in the combustion chamber (84), thereby achieving adjustable thrust of the engine (8); The top of the oxidant storage tank (5) is provided with an air inlet (51), which is connected to a pressurizing device. The pressurizing device has a plurality of water outlets (55) arranged along the circumference of the bottom, and each group of water outlets (55) is connected to a corresponding group of water supply pipelines (7); The interior of the oxidant storage tank (5) is divided into a heating zone and a drainage zone, the heating zone is close to the air inlet (51), and the drainage zone is close to the water outlet (55); the electric heating device comprises a U-shaped electric heating rod (54), and the U-shaped electric heating rod (54) is installed in the heating zone inside the oxidant storage tank (5) and is evenly arranged along the circumference of the inner wall of the heating zone.

2. A thermoelectric hybrid rocket engine according to claim 1, characterized in that: The pressurizing device adopts a high-pressure gas cylinder (1), in which high-pressure inert gas is stored, and the high-pressure gas cylinder (1) is connected to the oxidant storage tank (5) through a gas supply pipeline.

3. A thermoelectric hybrid rocket engine according to claim 2, characterized in that: A pressure reducing valve (3) and a gas supply valve (4) are arranged on the gas supply pipeline between the high-pressure gas cylinder (1) and the oxidant storage tank (5); the pressure reducing valve (3) is arranged close to the high-pressure gas cylinder (1), and the gas supply valve (4) is arranged on a side of the pressure reducing valve (3) away from the high-pressure gas cylinder (1); after the gas in the high-pressure gas cylinder (1) is reduced in pressure by the pressure reducing valve (3), the timing of filling into the oxidant storage tank (5) is controlled by the gas supply valve (4).

4. A thermoelectric hybrid rocket engine according to claim 1, characterized in that: An engine heat insulation layer (82) is provided inside the engine casing (81) for isolating the engine casing (81) from high-temperature fuel gas, thereby extending the service life of the engine (8); an oxidant storage tank heat insulation layer (53) is provided inside the oxidant storage tank (5), and the oxidant storage tank heat insulation layer (53) completely wraps the inner wall of the oxidant storage tank (5), thereby slowing down the heat transfer of the saturated liquid oxidant in the oxidant storage tank (5) and reducing energy loss.

5. A thermoelectric hybrid rocket engine according to claim 1, characterized in that: The fuel tank (87) stores metal fuel inside, which is freely loaded in the form of powder or placed in the fuel tank (87) in the form of powder; an elastic pad (86) is filled between the fuel tank (87) and the inner wall of the engine housing (81) to protect the fuel tank (87) from being damaged by impact.

6. A thermoelectric hybrid rocket engine according to claim 1, characterized in that: The tail nozzle (85) adopts a convergent-divergent nozzle, and the high-temperature and high-pressure combustion gas increases its flow velocity through the expansion of the convergent-divergent nozzle.

Images