A pulse liquid rocket engine with electrolytic ignition of a hydroxylammonium nitrate-based propellant

Abstract

This invention discloses a pulsed liquid rocket engine with electrolytic ignition of hydroxylamine nitrate propellant, belonging to the field of engine technology. It includes a pressure tank, a propellant storage tank, solenoid valves, electrode sections, a combustion chamber, and a tail nozzle. The propellant stored in the propellant storage tank is hydroxylamine nitrate propellant. A first solenoid valve controls the propellant loading, the electrode section and combustion chamber are used for electrolytic ignition of the fuel, and a second solenoid valve controls the emission of high-temperature, high-pressure gas to generate thrust. Under the control of the first solenoid valve, the hydroxylamine nitrate propellant is injected into the electrode section and combustion chamber through the injection port, contacts the cathode and anode of the electrodes, forms a circuit, and completes electrolytic ignition in the electrode section. Combustion then continues, and the resulting high-temperature gas flow is ejected through the tail nozzle under the control of the second solenoid valve, generating thrust. This invention solves the problems of electrode design and pulsed thrust chamber layout in the electrolytic ignition of hydroxylamine nitrate propellant, enabling the propulsion device to be used long-term and repeatedly.

Description

Technical Field

[0001] This invention relates to the field of engines, and more particularly to a pulsed liquid rocket engine with electrolytic ignition of hydroxylamine nitrate propellant. Background Technology

[0002] Since 1966, hydrazine fuels have been widely used as a classic single-component rocket propellant. However, hydrazine and hydrazine-based fuels are highly toxic, causing environmental pollution, harming the health of operators, and triggering a series of safety issues. Therefore, the development of a new generation of environmentally friendly, low-freezing-point, high-density green propellants has become a hot topic in recent years. Currently, the most researched high-energy liquid propellants mainly include hydrazine nitroformate (HNF), hydroxylammonium nitrate (HAN), and ammonium dinitramide (ADN). These fuels have high density, specific impulse comparable to anhydrous hydrazine, and are environmentally friendly. Therefore, engines using these fuels have better safety and are suitable for reuse to reduce costs.

[0003] Compared to nitrocellulose and dinitramide, hydroxylamine nitrate has relatively lower preheating and combustion chamber temperatures, resulting in simpler engine structures and longer service life. Currently, the mainstream ignition method for hydroxylamine nitrate is catalytic heating, but this method suffers from two main problems: a relatively short catalyst life and a large dead weight in the preheating device. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a pulsed liquid rocket engine with electrolytic ignition using hydroxylamine nitrate propellant. This engine utilizes the ionic liquid properties of hydroxylamine nitrate propellant for electrolytic ignition and startup, eliminating the need for additional heating devices.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A pulsed liquid rocket engine with electrolytic ignition of hydroxylamine nitrate propellant includes a pressure tank, a propellant storage tank, a first solenoid valve, an electrode section and a combustion chamber, a second solenoid valve and a tail nozzle, wherein the propellant stored in the propellant storage tank is hydroxylamine nitrate propellant.

[0007] The first solenoid valve is used to control the propellant loading, the electrode section and combustion chamber are used for fuel electrolysis and ignition, and the second solenoid valve is used to control the emission of high-temperature and high-pressure gas to generate thrust. Under the control of the first solenoid valve, the hydroxylamine nitrate propellant is injected into the electrode section and combustion chamber through the injection port, contacts the electrode cathode and anode, forms a circuit, and completes electrolysis, ignition and combustion in the electrode section. The high-temperature gas flow generated by combustion is ejected through the tail nozzle under the control of the second solenoid valve to generate thrust.

[0008] Preferably, temperature sensors and pressure sensors are installed in the electrode section and the combustion chamber.

[0009] Preferably, the electrode segment and the electrode installed in the combustion chamber are a pair of cylindrical porous electrode structures.

[0010] Preferably, the axis of the cylindrical porous electrode structure intersects perpendicularly with the axis of the electrode segment and the combustion chamber, a gap is left between the two electrodes, and the axial length of a single electrode is adjustable.

[0011] Preferably, the electrode segment and the electrode installed in the combustion chamber are axial patch or plated electrode structures.

[0012] Preferably, patch or plated electrodes are installed on the inner wall of the electrode section and the combustion chamber, electrodes with the same properties are symmetrical about the axis, gaps are left between adjacent electrodes, and the radial thickness of a single electrode is adjustable.

[0013] Preferably, the patch or plated electrode has a porous structure.

[0014] Preferably, in the electrode segment and the electrode structure installed in the combustion chamber, the effective area ratio of the anode to the cathode is between 0.8 and 1.5.

[0015] Preferably, the electrode segment and the electrode structure installed in the combustion chamber form a circuit with the outside world to achieve the electrolytic ignition function.

[0016] The above-mentioned electrolytic ignition method for a pulsed liquid rocket engine using hydroxylamine nitrate propellant includes:

[0017] The first solenoid valve is opened, and the propellant enters the electrode section and combustion chamber under the pressure of the pressurized gas tank. After the hydroxylamine nitrate propellant gradually fills the entire cavity, the first solenoid valve is closed.

[0018] When the electrode structure installed in the electrode section and combustion chamber is energized, the temperature and pressure in the electrode section and combustion chamber rise. When the temperature sensor and pressure sensor detect that the temperature and pressure have reached a certain threshold, the second solenoid valve is opened, and the high-temperature and high-pressure gas generated is ejected from the tail nozzle, generating thrust.

[0019] The beneficial effects of this invention are as follows: Utilizing the ionic liquid properties of hydroxylamine nitrate propellant, the electrode structure of the electrode section can be flexibly designed to achieve the target requirements of electrolytic ignition and start-up; the emission of high-temperature, high-pressure gas is controlled through solenoid valves, pressure sensors, and temperature sensors to achieve the target requirements of thrust generation. This engine structure is simpler, easier to control and miniaturize, easier to reuse, and has a longer service life. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an engine structure in an embodiment of the present invention, showing that the electrode segment is a cylindrical porous electrode;

[0021] Figure 2 This is a schematic diagram of an engine structure in an embodiment of the present invention, showing an electrode segment that is an axial patch or a plated electrode;

[0022] Figure 3 This is a schematic diagram showing the electrolysis process before ignition, as illustrated in an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram showing the electrolytic ignition process according to an embodiment of the present invention;

[0024] Figure 5 This is a temperature change curve of the electrolytic ignition of hydroxylamine nitrate aqueous solution shown in an embodiment of the present invention;

[0025] In the diagram: 1-Pressure gas tank, 2-Propellant storage tank, 3-First solenoid valve, 4-Electrode section and combustion chamber, 5-Second solenoid valve, 6-Tail nozzle. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the invention.

[0027] The pulsed liquid rocket engine with hydroxylamine nitrate propellant electrolytic ignition proposed in this invention consists of a pressure tank 1, a propellant storage tank 2, a first solenoid valve 3, an electrode section and combustion chamber 4, a second solenoid valve 5, and a tail nozzle 6. Operating in a pulsed mode, the first solenoid valve controls propellant loading, the electrode section and combustion chamber 4 perform electrolytic ignition of the fuel, and the second solenoid valve 5 controls the emission of high-temperature, high-pressure gas to generate thrust.

[0028] The first solenoid valve 3 and the second solenoid valve 5 are connected to the control system, which can regulate the propellant flow rate and working time. Electrodes, temperature sensors, and pressure sensors are installed in the electrode section and combustion chamber 4. This invention uses valves and pressure and temperature sensors to control the injection of high-temperature, high-pressure gas and generate thrust. The electrodes are connected to the outside world via bolts or auxiliary fixing mesh that penetrate the electrode section and combustion chamber walls to form a circuit, thereby achieving electrolytic ignition.

[0029] The design of the electrode structure is crucial. This invention designs different electrode structures to meet different application requirements; for engines with high thrust, the anode and cathode adopt a cylindrical porous electrode design, while for engines with low thrust, the electrodes adopt a patch or plated electrode design.

[0030] Regarding the design of the electrode segment Figure 1 The diagram shows a schematic of a two-segment cylindrical porous dielectric electrode structure. In this design, the axis of the cylindrical electrode intersects perpendicularly with both the electrode segment and the combustion chamber axis, with a gap between the two cylindrical electrodes. The area of ​​a single electrode is calculated by multiplying the effective area per unit volume (related to the pore size) by the cross-sectional area of ​​the thrust chamber by the axial length of a single electrode. Therefore, different electrolysis performances can be achieved by controlling the axial lengths of the two electrodes and the different pore sizes of the porous electrode.

[0031] In one specific embodiment of the present invention, an asymmetric area cathode and anode electrode structure is used to achieve better electrolysis performance and a lighter structure. In the cylindrical porous dielectric electrode structure, the lengths L1 and L2 of the two porous electrode segments are controlled to control the total area ratio of the anode and cathode, thereby obtaining the best electrolysis effect. Within the voltage range of 0-60V, the effective area ratio of the anode and cathode is optimally controlled between 0.8 and 1.5. By adjusting the axial length of the electrode segments and the pore size, the ratio of the total electrode area to the combustion chamber volume is controlled, thereby enhancing the electrolysis effect and shortening the response time.

[0032] For the power units required by small spacecraft such as microsatellites, the electrode sections can be constructed by pre-embedding the electrodes within an insulating outer shell, such as... Figure 2 The diagram illustrates an axially patched or plated electrode structure. Taking two pairs of anode and cathode electrodes as an example, the top and bottom electrodes are a pair of anodes, and the left and right electrodes are a pair of cathodes. Electrodes with similar properties are symmetrical about the axis, with gaps between adjacent electrodes. This structure, with good thermal insulation, achieves excellent electrolytic performance due to its naturally large surface area to volume ratio within a small size. The surface area of ​​the anode and cathode is controlled by adjusting the ratio of the arc angles θ1 and θ2 of the anode and cathode. Within the 0-60V voltage range, the optimal ratio of the effective area of ​​the anode to cathode is controlled between 0.8 and 1.5. By adjusting the radial thickness and pore size of the electrodes, the ratio of the total electrode area to the combustion chamber volume is controlled, enhancing the electrolytic effect and shortening the response time.

[0033] Under the control of the first solenoid valve, the hydroxylamine nitrate propellant is injected into the electrode section and combustion chamber through the injection port, contacting the electrode cathode and anode to form a circuit and complete electrolytic ignition and combustion in the electrode section; the high-temperature gas flow generated by combustion is ejected through the tail nozzle under the control of the second solenoid valve to generate thrust.

[0034] Figure 3-4Taking a two-section cylindrical porous dielectric electrode structure as an example, the working principle of this liquid rocket engine is specifically demonstrated. The pressurized gas tank 1 is responsible for propelling the hydroxylamine nitrate propellant in the propellant storage tank 2. The first solenoid valve 3 is normally closed. When the first solenoid valve 3 opens, the propellant enters the electrode section and combustion chamber 4 under pressure. By controlling the pressure of the pressurized gas tank and the opening time of the first solenoid valve, the flow rate and working time of the hydroxylamine nitrate propellant can be regulated. Since the second solenoid valve 5 is normally closed, the hydroxylamine nitrate propellant gradually fills the entire cavity, such as... Figure 3 As shown. After the cavity is filled with hydroxylamine nitrate propellant, the first solenoid valve 3 closes, energizing the electrodes to initiate electrolytic ignition and subsequent rapid combustion. The temperature / pressure in the electrode section and combustion chamber 4 rises. When the temperature and pressure sensors detect that the temperature / pressure has reached a certain threshold, the second solenoid valve 5 opens, and the resulting high-temperature, high-pressure gas is ejected from the tailpipe 6, generating thrust. Figure 4 As shown.

[0035] like Figure 5 As shown, when an 80% hydroxylamine nitrate aqueous solution is used for electrolytic ignition, the temperature of the electrode section and the combustion chamber will change in the following two stages: First, the temperature rises rapidly to about 120°C, then the rate of increase slows down, and when it reaches about 180°C, the temperature rises rapidly again, with the highest temperature reaching over 290°C.

[0036] A liquid rocket engine using electrolytic ignition with an aqueous solution of hydroxylamine nitrate has a relative molecular mass of approximately 29.2 kg / kmol for its gaseous products and a specific heat ratio of approximately 1.3. If the combustion chamber pressure is taken as 1 MPa and the combustion chamber temperature as 300℃, theoretical calculations show that the engine's theoretical specific impulse is approximately 120 s. If the combustion chamber temperature is taken as 600℃, theoretical calculations show that the engine's theoretical specific impulse can reach approximately 150 s. The higher the combustion chamber temperature, the greater the specific impulse of the rocket engine.

[0037] The above description is merely a glimpse into the specific content and operation of this invention, but the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this invention should be included within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A pulsed liquid rocket engine with electrolytic ignition of hydroxylamine nitrate propellant, characterized in that, It includes a pressure tank (1), a propellant storage tank (2), a first solenoid valve (3), an electrode section and a combustion chamber (4), a second solenoid valve (5) and a tail nozzle (6). The propellant stored in the propellant storage tank (2) is hydroxylamine nitrate propellant. The electrode structure forms a circuit with the outside world. The first solenoid valve (3) is used to control the injection of propellant, the electrode section and combustion chamber (4) are used for the electrolytic ignition of fuel, and the second solenoid valve (5) is used to control the emission of high temperature and high pressure gas to generate thrust. Under the control of the first solenoid valve, the hydroxylamine nitrate propellant is injected into the electrode section and combustion chamber through the injection port, contacts the electrode cathode and anode, forms a circuit, and completes electrolytic ignition and combustion in the electrode section. The high temperature gas flow generated by combustion is ejected through the tail nozzle under the control of the second solenoid valve to generate thrust. The electrolytic ignition method is as follows: the first solenoid valve (3) is opened, and the propellant enters the electrode section and combustion chamber (4) under the pressure of the pressure tank (1). After the hydroxylamine nitrate propellant gradually fills the entire cavity, the first solenoid valve (3) is closed. The electrode structure installed in the electrode section and combustion chamber (4) is energized, and the temperature and pressure in the electrode section and combustion chamber (4) rise. When the temperature sensor and pressure sensor detect that the temperature and pressure have reached a certain threshold, the second solenoid valve (5) is opened. The electrodes installed in the electrode section and combustion chamber (4) are a pair of cylindrical porous electrode structures, and the effective area ratio of the anode and cathode is between 0.8 and 1.5; the axis of the cylindrical porous electrode structure intersects perpendicularly with the axis of the electrode section and combustion chamber, and there is a gap between the two electrodes, and the axial length of a single electrode is adjustable. Alternatively, the electrodes installed in the electrode segment and combustion chamber (4) may be axially patched or plated electrode structures.

2. The pulsed liquid rocket engine with electrolytic ignition of hydroxylamine nitrate propellant according to claim 1, characterized in that, Temperature sensors and pressure sensors are installed in the electrode section and combustion chamber (4).

3. The pulsed liquid rocket engine with electrolytic ignition of hydroxylamine nitrate propellant according to claim 1, characterized in that, Patch or plated electrodes are installed on the inner wall of the electrode section and combustion chamber (4). Electrodes with the same properties are symmetrical about the axis center. There is a gap between adjacent electrodes. The radial thickness of a single electrode is adjustable.

4. The pulsed liquid rocket engine with electrolytic ignition of hydroxylamine nitrate propellant according to claim 1, characterized in that, The patch or plated electrode has a porous structure.

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