Catalytic igniter
By designing electromagnetic heating elements and catalytic bed baffle structures, the problems of low heating efficiency and catalyst sintering in the nitrous oxide catalytic decomposition device were solved, achieving efficient catalyst decomposition and rapid ignition, which is suitable for propellant decomposition in space monocomponent engines.
Patent Information
- Application Number
- CN202511801851.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-03-03
AI Technical Summary
Existing nitrous oxide catalytic decomposition devices suffer from low heating efficiency, high heat dissipation, low catalyst utilization, and catalyst sintering problems caused by large internal temperature gradients in the catalytic bed, making it difficult to achieve rapid response and multiple reuses.
The system employs an electromagnetic heating element and a catalyst bed baffle structure. The electromagnetic heating element heats the propellant to the second target temperature and brings it into contact with the catalyst, thereby shortening the temperature difference between the catalyst and the propellant and improving the catalyst decomposition efficiency. The system is combined with a heating coil and insulation to reduce heat loss and ensure uniform heating.
It improves the decomposition efficiency of the catalyst, shortens the ignition start-up time, realizes the rapid response and multiple reuse of the catalytic igniter, has a simple and compact structure, and can monitor the catalyst temperature and chamber pressure in real time.
Smart Images
Figure CN121593922A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aerospace technology, and in particular to a catalytic igniter. Background Technology
[0002] Monocomponent propellants are widely used for attitude control in satellites, spacecraft, and space probes, characterized by system simplicity and high reliability. Commonly used monocomponent propellants include anhydrous hydrazine and DT-3 (a mixture of anhydrous hydrazine, nitric acid, hydrazine, and water), but these propellants are toxic and polluting. With increasingly stringent environmental protection requirements, developing non-toxic and non-polluting monocomponent propellants has become a goal for major spacefaring nations.
[0003] Nitrous oxide is a colorless gas at room temperature and pressure. It can be compressed and liquefied to exist in a gas-liquid two-phase state. It is non-toxic, non-corrosive, stable, and easy to store. It also has a high saturated vapor pressure, which can be self-pressurized for propellant supply, simplifying system structure and reducing propellant system mass. The minimum temperature for the catalytic decomposition of nitrous oxide is between 300℃ and 400℃, where it decomposes into oxygen and nitrogen. The resulting high-temperature combustion gas can be used not only in single-component engines but also as a catalytic igniter to ignite bi-component propellants, achieving rapid ignition in the combustion chamber.
[0004] Improving the decomposition efficiency of propellants is a pressing technical problem that the industry needs to solve. Summary of the Invention
[0005] The purpose of this invention is to provide a catalytic igniter for improving the decomposition efficiency of propellants.
[0006] To achieve the above objectives, the present invention provides a catalytic igniter for decomposing propellants. The catalytic igniter includes: a decomposition chamber, a spray plate, an electromagnetic heating element, a heating coil, and a catalytic bed baffle. Along the axial direction of the decomposition chamber, the chamber has opposing first and second ends, and a receiving cavity penetrating the chamber; the spray plate is disposed at the first end of the decomposition chamber, located outside the receiving cavity; the electromagnetic heating element is located inside the receiving cavity; the first end of the electromagnetic heating element abuts against the spray plate; the electromagnetic heating element has a first through hole penetrating the electromagnetic heating element along its thickness direction; the heating coil is disposed on the outer wall of the decomposition chamber; the catalytic bed baffle is located inside the receiving cavity, near the second end of the decomposition chamber; the catalytic bed baffle has a second through hole penetrating the catalytic bed baffle along its thickness direction; the electromagnetic heating... The thickness direction of the component, the thickness direction of the catalyst bed baffle, and the axial direction of the decomposition chamber are aligned; there is a space between the catalyst bed baffle and the electromagnetic heating component, which is used to accommodate the catalyst; under the action of the heating coil, the electromagnetic heating component and the decomposition chamber heat the catalyst to a first target temperature; under the action of the heating coil, the electromagnetic heating component heats the propellant to a second target temperature; after the propellant with the second target temperature comes into contact with the catalyst with the first target temperature, the propellant with the second target temperature is heated to a third target temperature; the third target temperature is greater than or equal to the decomposition threshold temperature of the propellant.
[0007] In the catalytic igniter provided by this invention, the propellant is heated to a second target temperature by an electromagnetic heating element under the action of a heating coil (it should be noted that the propellant heating here is based on the propellant heating used in the prior art, not by first lowering the temperature of the propellant commonly used in the prior art and then raising the temperature of the propellant using the technology of this application, so as to avoid the situation where the temperature of the propellant with the second target temperature is lower than the temperature of the propellant commonly used in the prior art). The propellant with the second target temperature comes into contact with the catalyst with the first target temperature, thus the temperature of the propellant in contact with the catalyst increases. Compared with the prior art, which directly brings the propellant at room temperature or below room temperature into contact with the catalyst heated to the first target temperature, in this application, when the propellant heated to the second target temperature comes into contact with the catalyst heated to the first target temperature, the probability of a significant drop in the temperature of the catalyst with the first target temperature due to an excessive temperature difference between the propellant and the catalyst can be reduced. Based on this, compared with the prior art, this application can shorten the time required for subsequent raising of the catalyst temperature and propellant temperature, improve the efficiency of catalyst decomposing the propellant, and shorten the ignition start-up time.
[0008] In one implementation, along the axial direction of the decomposition chamber, the decomposition chamber includes a straight cylindrical section and a tail nozzle connected in sequence; a heating coil is disposed on the outer wall of the straight cylindrical section; The straight section includes a first straight section and a second straight section, the second straight section being located between the first straight section and the tail nozzle; the injection disc is disposed at the free end of the first straight section; The height of the receiving cavity located in the first straight cylindrical section is greater than the height of the receiving cavity located in the second straight cylindrical section; The second end of the electromagnetic heating element abuts against the junction of the first straight cylinder portion and the second straight cylinder portion; the catalyst bed baffle and the catalyst are both located in the receiving cavity corresponding to the second straight cylinder portion, and the catalyst bed baffle abuts against the junction of the second straight cylinder portion and the tail nozzle.
[0009] In one implementation, the average diameter of the straight cylindrical portion is greater than or equal to 10 mm and less than or equal to 30 mm; the length of the straight cylindrical portion is greater than or equal to 30 mm and less than or equal to 60 mm.
[0010] In one implementation, along the axial direction of the decomposition chamber, the tailpipe includes a first tailpipe and a second tailpipe connected in sequence; the first tailpipe is connected to the second straight section. Along the direction away from the injection disk, the diameter of the first tail nozzle gradually decreases, and the diameter of the second tail nozzle gradually increases. The first tail nozzle and the second tail nozzle have a throat, the diameter of which is greater than or equal to 0.5 mm and less than or equal to 2 mm.
[0011] In one implementation, the electromagnetic heating element has a plurality of uniformly distributed first through holes; The diameter of the first through hole is greater than or equal to 0.5 mm and less than or equal to 1 mm; The number of the first through holes is greater than or equal to 20 and less than or equal to 40.
[0012] In one implementation, the catalyst is a catalyst particle, and the diameter of the second through hole is smaller than the diameter of the catalyst particle; The catalyst bed baffle has a plurality of uniformly distributed second through holes; The thickness of the catalytic bed baffle is greater than or equal to 2 mm and less than or equal to 3 mm.
[0013] In one implementation, a third through hole and a fourth through hole are provided on the second straight cylindrical portion along the radial direction of the decomposition chamber; both the third through hole and the fourth through hole communicate with the receiving cavity; The catalytic igniter also includes: A temperature measuring connector is disposed on the second straight cylindrical portion and communicates with the third through hole; A pressure testing connector is disposed on the second straight cylindrical portion and communicates with the fourth through hole.
[0014] In one implementation, the catalytic igniter further includes: A seal is located between the injection disc and the first end of the decomposition chamber to achieve a seal between the injection disc and the decomposition chamber.
[0015] In one implementation, the material of the electromagnetic heating element is the same as that of the decomposition chamber; the materials of the electromagnetic heating element and the decomposition chamber include nickel-iron-niobium alloy.
[0016] In one implementation, the catalytic igniter further includes: a heat insulation element disposed on the outer wall of the straight cylindrical portion; the outer wall of the heat insulation element is provided with a plurality of spiral grooves, and the heating coil is wound around the outer wall of the heat insulation element and located within the spiral grooves. Attached Figure Description
[0017] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a cross-sectional view of the catalytic igniter in an embodiment of the present invention; Figure 2 As described in the embodiments of the present invention Figure 1 Enlarged structural diagram at point II; Figure 3 As described in the embodiments of the present invention Figure 1 Enlarged structural diagram at point I; Figure 4 This is a schematic diagram of the structure of the first thermal insulation component in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the second insulation component in an embodiment of the present invention.
[0018] Figure label: 1-Catalytic igniter, 2-Decomposition chamber, 20-Straight cylinder section, 21-Tail nozzle, 22-First straight cylinder section, 23-Second straight cylinder section, 24-First tail nozzle, 25-Second tail nozzle, 26-Throat, 3-Injection plate, 4-Electromagnetic heating element, 40-First through hole, 5-Catalytic bed baffle, 50-Second through hole, 6-Catalyst, 7-Gas outlet connector, 8-Temperature measuring connector, 9-Pressure measuring connector, 10-First boss, 11-Second boss, 12-Sealing element, 13-Heating coil, 140-First insulation element, 141-Second insulation element. Detailed Implementation
[0019] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0020] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.
[0022] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0024] In the background section, most commonly used nitrous oxide catalytic decomposition devices currently employ either external or internal heating. Externally heated catalytic decomposition devices suffer from low heating efficiency, increased heat dissipation, and low catalyst utilization. In such cases, the catalytic bed merely serves a heating function, resulting in a long ignition start-up time. Internally heated catalytic decomposition devices exhibit a large internal temperature gradient within the catalytic bed, which can easily lead to catalyst sintering, damage to the heater, and difficulty in repeated use. Furthermore, when nitrous oxide is used in catalytic igniters, rapid response and multiple reuses are required.
[0025] To address at least one of the aforementioned technical problems, the present invention provides a catalytic igniter for decomposing propellants. The propellants include nitrous oxide, HAN-based (i.e., hydroxylamine nitrate), or AND-based (i.e., nitramide), etc.
[0026] See Figure 1 The catalytic igniter 1 includes: a decomposition chamber 2, an injection disk 3, an electromagnetic heating element 4, a heating coil 13, and a catalytic bed baffle 5. Along the axial direction A of the decomposition chamber 2, the decomposition chamber 2 has a first end and a second end opposite to each other, and a receiving cavity penetrating the decomposition chamber 2; the injection disk 3 is disposed at the first end of the decomposition chamber 2 and located outside the receiving cavity; exemplaryly, the injection disk 3 is disposed outside the decomposition chamber 2 and connected to the first end of the decomposition chamber 2. An electromagnetic heating element 4 is located within the receiving cavity, with its first end abutting against the injection disk 3. The electromagnetic heating element 4 has a first through-hole 40 extending through it along its thickness direction. A heating coil 13 is disposed on the outer wall of the decomposition chamber 2. A catalyst bed baffle 5 is located within the receiving cavity, near its second end in the decomposition chamber 2. The catalyst bed baffle 5 has a second through-hole 50 extending through it along its thickness direction. A receiving space exists between the catalyst bed baffle 5 and the electromagnetic heating element 4, which is used to receive the catalyst 6. Under the action of the heating coil 13, the electromagnetic heating element 4 and the decomposition chamber 2 heat the catalyst to a first target temperature. Under the action of the heating coil 13, the electromagnetic heating element 4 heats the propellant to a second target temperature. After the propellant at the second target temperature comes into contact with the catalyst at the first target temperature, the propellant at the second target temperature is heated to a third target temperature. The third target temperature is greater than or equal to the decomposition threshold temperature of the propellant. That is, the catalyst at the first target temperature heats the propellant at the second target temperature to the third target temperature.
[0027] It should be noted that the injection disk 3 can be found in existing technology and is not specifically limited here. The thickness direction of the catalyst bed baffle 5, the thickness direction of the electromagnetic heating element 4, and the axial direction A of the decomposition chamber 2 are aligned. The aforementioned "decomposition threshold temperature" can be understood as the decomposition temperature of the propellant.
[0028] See Figure 1In the catalytic igniter 1 provided in this embodiment of the invention, the electromagnetic heating element 4 heats the propellant to a second target temperature under the action of the heating coil 13 (it should be noted that the propellant heating here is based on the propellant heating used in the prior art, and is not a process of first lowering the temperature of the propellant commonly used in the prior art and then using the technology of this application to raise the temperature of the propellant, so as to avoid the situation where the temperature of the propellant with the second target temperature is lower than the temperature of the propellant commonly used in the prior art). The propellant with the second target temperature comes into contact with the catalyst with the first target temperature, thereby indicating that the temperature of the propellant in contact with the catalyst 6 increases. Compared with the prior art, which directly contacts the propellant at room temperature or below room temperature with the catalyst 6 heated to the first target temperature, in this application, when the propellant heated to the second target temperature comes into contact with the catalyst 6 heated to the first target temperature, the probability of a significant drop in the temperature of the catalyst 6 with the first target temperature due to an excessively large temperature difference between the propellant and the catalyst 6 can be reduced. Based on this, compared with the prior art, this application can shorten the time required to subsequently raise the temperature of catalyst 6 and propellant, improve the efficiency of catalyst 6 in decomposing propellant, and shorten the ignition start-up time.
[0029] As one possible implementation, the specific value of the first target temperature can be set according to actual needs, and is not specifically limited here. For example, the first target temperature is greater than the decomposition threshold temperature.
[0030] As one possible implementation, see Figure 1 The catalytic igniter 1 also includes a gas outlet connector 7, which is located at the second end of the decomposition chamber 2. In actual use, the high-temperature gas generated after the propellant's catalytic decomposition is ejected along the gas outlet connector 7. Furthermore, the gas outlet connector 7 can be connected to the thrust chamber to ignite the bicomponent propellant within it.
[0031] As one possible implementation, see Figure 1Along the axial direction of the decomposition chamber 2, the decomposition chamber 2 includes a straight cylindrical section 20 and a tail nozzle 21 connected in sequence. A heating coil 13 is disposed on the outer wall of the straight cylindrical section 20; the straight cylindrical section 20 includes a first straight cylindrical section 22 and a second straight cylindrical section 23, the second straight cylindrical section 23 being located between the first straight cylindrical section 22 and the tail nozzle 21. An injection disk 3 is disposed at the free end of the first straight cylindrical section 22, that is, at the end of the first straight cylindrical section 22 away from the second straight cylindrical section 23. The height of the receiving cavity located in the first straight cylindrical section 22 is greater than the height of the receiving cavity located in the second straight cylindrical section 23; an electromagnetic heating element 4 is located inside the first straight cylindrical section 22, and the second end of the electromagnetic heating element 4 abuts against the junction of the first straight cylindrical section 22 and the second straight cylindrical section 23. A catalyst bed baffle 5 and a catalyst 6 are both located in the corresponding receiving cavities of the second straight cylindrical section 23, and the catalyst bed baffle 5 abuts against the junction of the second straight cylindrical section 23 and the tail nozzle 21.
[0032] Because the height of the receiving cavity in the first straight cylindrical section 22 is greater than the height of the receiving cavity in the second straight cylindrical section 23, the electromagnetic heating element 4 is located inside the first straight cylindrical section 22, and its second end abuts against the junction of the first straight cylindrical section 22 and the second straight cylindrical section 23. At this time, the electromagnetic heating element 4 is axially positioned and fixed within the first straight cylindrical section 22, preventing it from moving during actual operation of the catalytic igniter 1 and ensuring its normal operation. Furthermore, the catalytic bed baffle 5 abuts against the junction of the second straight cylindrical section 23 and the tailpipe. At this time, the catalytic bed baffle 5 is axially positioned and fixed within the second straight cylindrical section 23, preventing it from moving during actual operation of the catalytic igniter 1 and ensuring its normal operation.
[0033] It should be noted that "the height of the receiving cavity located in the first straight cylindrical section 22 is greater than the height of the receiving cavity located in the second straight cylindrical section 23" can be understood as the inner diameter of the first straight cylindrical section 22 being greater than the inner diameter of the second straight cylindrical section 23.
[0034] In one alternative approach, see Figure 1 The average diameter of the straight cylindrical section 20 is greater than or equal to 10 mm and less than or equal to 30 mm; the length of the straight cylindrical section 20 is greater than or equal to 30 mm and less than or equal to 60 mm. When the average diameter and length of the straight cylindrical section 20 are within the above range, it is suitable for nitrous oxide flow rates of 1 g / s to 3 g / s, ensuring complete decomposition of nitrous oxide.
[0035] For example, the average diameter of the straight cylindrical portion 20 can be 10mm, 12mm, 15mm, 20mm, 22mm, 25mm, 28mm, or 30mm, etc. The length of the straight cylindrical portion 20 can be 30mm, 32mm, 35mm, 40mm, 42mm, 45mm, 48mm, 50mm, 52mm, 55mm, 58mm, or 60mm, etc.
[0036] In one alternative approach, see Figure 1 Along the axial direction of the decomposition chamber 2, the tail nozzle 21 includes a first tail nozzle 24 and a second tail nozzle 25 connected in sequence; the first tail nozzle 24 is connected to the second straight section 23. Along the direction away from the injection disk 3, the diameter of the first tail nozzle 24 gradually decreases, and the diameter of the second tail nozzle 25 gradually increases. A throat 26 is provided between the first tail nozzle 24 and the second tail nozzle 25, and the diameter of the throat 26 is greater than or equal to 0.5 mm and less than or equal to 2 mm. For example, the diameter of the throat 26 can be 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, or 2 mm, etc.
[0037] See Figure 1 When the diameter of the throat 26 is within the above-mentioned range, it is suitable for nitrous oxide flow rates of 1 g / s to 3 g / s. When the diameter of the throat 26 is less than 0.5 mm, it will lead to an increase in the chamber pressure of the decomposition chamber 2, resulting in insufficient strength of the decomposition chamber 2 and affecting the decomposition of nitrous oxide. When the diameter of the throat 26 is greater than 2 mm, the chamber pressure of the decomposition chamber 2 decreases, the residence time of gaseous nitrous oxide in the decomposition chamber 2 is shortened, and the catalytic efficiency decreases.
[0038] In some embodiments, see Figure 1 The contraction angle B of the first tail nozzle 24 is greater than or equal to 30° and less than or equal to 60°. The expansion angle D of the second tail nozzle 25 is greater than or equal to 10° and less than or equal to 45°. For example, the contraction angle B of the first tail nozzle 24 can be 30°, 35°, 40°, 45°, 50°, 55°, or 60°, etc. The expansion angle D of the second tail nozzle 25 can be 10°, 15°, 20°, 25°, 30°, 35°, 40°, or 45°, etc.
[0039] As one possible implementation, see Figure 1The electromagnetic heating element 4 has multiple uniformly distributed first through holes 40. These uniformly distributed first through holes 40 facilitate a uniform flow field, prevent catalyst sintering, and improve catalyst lifespan. Specifically, in this application, the electromagnetic heating element 4 has multiple uniformly arranged first through holes 40, ensuring that the propellant enters the catalyst 6 uniformly, preventing catalyst sintering, and thus improving the service life and reusability of the catalytic igniter 1. That is, the electromagnetic heating element 4 has multiple uniformly arranged first through holes 40, which can achieve a uniform flow after the propellant flows through, resulting in a uniform flow field. If the flow field is non-uniform, more propellant will flow through certain areas when the propellant passes through the catalyst, and the exothermic reaction can cause catalyst sintering. If the flow field is uniform, the heat will be evenly distributed, making localized sintering less likely and increasing service life.
[0040] As one possible implementation, see Figure 1 The diameter of the first through hole 40 is greater than or equal to 0.5 mm and less than or equal to 1 mm; the number of first through holes 40 is greater than or equal to 20 and less than or equal to 40. For example, the diameter of the first through hole 40 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm, etc. The number of first through holes 40 can be 20, 22, 25, 28, 30, 32, 35, 38, or 40.
[0041] As one possible implementation, see Figure 1 Catalyst 6 is composed of catalyst particles, and the diameter of the second through hole 50 is smaller than the diameter of the catalyst particles. At this time, the catalyst bed baffle 5 can be used to fix and support the catalyst 6, preventing it from being ejected from the decomposition chamber 2 along with the propellant during the actual catalytic decomposition of the propellant, thus avoiding waste of the catalyst 6, reducing catalyst loss, and improving the utilization rate of the catalyst 6.
[0042] In some embodiments, the catalyst 6 is generally a spherical or columnar structure with a size of 1.2 mm to 2.5 mm, therefore the diameter of the second through hole 50 is greater than or equal to 0.5 mm and less than or equal to 1 mm. For example, the pore size of the second through hole 50 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm, etc.
[0043] As one possible implementation, see Figure 1 The catalyst bed baffle 5 has multiple uniformly distributed second through holes 50; this is beneficial for uniform flow field, heat exchange and propellant decomposition.
[0044] As one possible implementation, see Figure 1The thickness of the catalyst bed baffle 5 is greater than or equal to 2 mm and less than or equal to 3 mm. For example, the thickness of the catalyst bed baffle 5 can be 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, or 3 mm, etc. When the thickness of the catalyst bed baffle 5 is within the above-mentioned range, it can stably fix and support the catalyst 6, preventing catalyst 6 leakage. In addition, the temperature inside the decomposition chamber 2 is high, and the strength of the catalyst bed baffle 5 with a thickness within the above-mentioned range can meet the actual working requirements.
[0045] In one alternative approach, see Figure 1 Along the radial direction of the decomposition chamber 2, the second straight cylindrical portion 23 is provided with a third through hole and a fourth through hole; both the third through hole and the fourth through hole communicate with the receiving cavity. The aforementioned third through hole and fourth through hole can be arranged opposite each other along the radial direction of the decomposition chamber 2, or they can be arranged offset along the radial direction of the decomposition chamber 2.
[0046] In one alternative approach, see Figure 1 The catalytic igniter 1 also includes a temperature measuring connector 8 and a pressure measuring connector 9. The temperature measuring connector 8 is disposed on the second straight cylindrical portion 23 and communicates with the third through hole. The pressure measuring connector 9 is disposed on the second straight cylindrical portion 23 and communicates with the fourth through hole.
[0047] See Figure 1 In practical use, the temperature measuring connector 8 houses a temperature sensor for real-time monitoring of the catalyst 6 temperature. Alternatively, the temperature measuring connector 8 can be connected to a sheathed thermocouple; by adjusting the thermocouple length, different radial temperatures of the catalyst 6 can be measured. The pressure measuring connector 9 houses a pressure measuring element for real-time monitoring of the chamber pressure within the decomposition chamber 2.
[0048] In some embodiments, see Figure 1 The second straight section 23 has a first boss 10 and a second boss 11 at the locations where the third and fourth through holes are opened. The temperature measuring connector 8 is welded to the first boss 10, and the pressure measuring connector 9 is welded to the second boss 11.
[0049] As one possible implementation, see Figure 1 and Figure 2 The catalytic igniter 1 also includes a sealing element 12, located between the injection plate 3 and the first end of the decomposition chamber 2, to achieve a seal between the injection plate 3 and the decomposition chamber 2. This not only ensures that the catalytic igniter 1 is sealed, preventing propellant leakage, but also ensures that the catalyst 6 is compressed and compacted when the catalytic igniter 1 is loaded with catalyst 6.
[0050] In one alternative approach, see Figure 1 and Figure 2The sealing element 12 can be a graphite gasket. In actual sealing, since the graphite gasket is compressible, a compression allowance needs to be reserved. When the bolt is tightened, the reserved compression allowance disappears, thereby achieving a seal between the injection plate 3 and the decomposition chamber 2.
[0051] As one possible implementation, see Figure 1 The electromagnetic heating element is made of the same material as the decomposition chamber.
[0052] In some embodiments, see Figure 1 The decomposition chamber 2 is made of a nickel-iron-niobium alloy, such as 1J47 or 1J87; in this case, the decomposition chamber 2 has the advantage of high temperature resistance. The electromagnetic heating element 4 can also be made of a nickel-iron-niobium alloy, such as 1J47 or 1J87.
[0053] This application employs electromagnetic heating, which results in low heat dissipation and therefore high heating efficiency. See also Figure 1 When the heating coil 13 is energized by an alternating current, it generates an alternating magnetic field. The electromagnetic heating element 4 and the straight section of the decomposition chamber 2, which are in the alternating magnetic field, will generate induced current, thereby heating the electromagnetic heating element 4 and the straight section of the decomposition chamber 2. The electromagnetic heating element 4 and the straight section of the decomposition chamber 2 heat the catalyst 6 through heat conduction.
[0054] In one alternative approach, see Figures 1 to 5 The catalytic igniter 1 also includes a heat insulation component, which is disposed on the outer wall of the straight cylindrical section. Multiple spiral grooves are formed on the outer wall of the heat insulation component, and the heating coil 13 is wound around the outer wall of the heat insulation component and located within the spiral grooves. The aforementioned heat insulation component serves to maintain heat, thereby reducing heat dissipation in the decomposition chamber 2, lowering heat loss, and improving catalytic decomposition efficiency.
[0055] In some embodiments, the insulation component may be made of ceramic, and the ceramic material may be Al2O3 or CaSiO3.
[0056] In some embodiments, see Figures 1 to 5 The insulation components include a first insulation component 140 and a second insulation component 141, which wrap around the outer wall of the straight cylindrical portion 20. The heating coil 13 is wound around the outer wall of the insulation components, which serves to fix the first insulation component 140 and the second insulation component 141.
[0057] The following possible implementation is used as an example to describe the assembly and use of the catalytic igniter, in which the propellant is nitrous oxide. It should be understood that the following description is for illustrative purposes only and is not intended to limit the specific implementation.
[0058] Combination Figures 1 to 5First, a first heat preservation component 140 and a second heat preservation component 141 are installed on the outer wall of the straight cylindrical part 20 of the decomposition chamber 2. After installation, a heating coil 13 is wound in the spiral grooves on the outer walls of the first heat preservation component 140 and the second heat preservation component 141. Next, the decomposition chamber 2 is sequentially welded to the temperature measuring connector 8, the pressure measuring connector 9, and the gas outlet connector 7 using argon arc welding. Next, the catalytic bed baffle 5, catalyst 6, and electromagnetic heating element 4 are sequentially installed or placed inside the containment cavity of the decomposition chamber 2; then, the graphite sealing gasket is installed, and the injection plate 3 and the decomposition chamber 2 are fastened together using bolts. This completes the assembly of the catalytic igniter 1.
[0059] After the catalytic igniter 1 is assembled, when it is in operation, an alternating current is input to both ends of the heating coil 13 to heat the straight section of the decomposition chamber 2 and the electromagnetic heating element 4, thereby raising the temperature of the catalyst 6 through heat conduction. Then, a temperature sensor measures the temperature of the catalyst 6. When the temperature of the catalyst 6 is higher than the decomposition threshold temperature of nitrous oxide, the valve opens, and gaseous / liquid nitrous oxide enters the decomposition chamber 2 through the injection plate 3. In the electromagnetic heating element, the nitrous oxide is fully preheated, and the preheated nitrous oxide comes into full contact with the catalyst 6, achieving rapid decomposition of nitrous oxide. The high-temperature gas produced by catalytic decomposition is injected along the gas outlet connector 7.
[0060] In summary, compared to traditional nitrous oxide catalytic decomposition devices, this invention uses an electromagnetic heating element 4 instead of the existing catalytic pre-bed structure. The electromagnetic heating element 4 preheats both the nitrous oxide and the catalyst 6. This not only increases the bed loading rate of the catalytic bed but also improves the decomposition efficiency of the catalyst 6 on the propellant, reducing the amount of catalyst 6 used. Furthermore, this application integrates the decomposition chamber 2, the insulation element, and the electromagnetic heating element 4 into a single unit. This not only results in high heating efficiency and low heat loss but also simplifies the structure of the catalytic igniter 1. In other words, the catalytic igniter 1 in this application has a simple and compact structure. Furthermore, the catalytic igniter 1 in this application, by setting a temperature measuring connector 8 and a pressure measuring connector 9, enables real-time monitoring of the catalyst 6 temperature and the chamber pressure of the decomposition chamber 2. Real-time monitoring can detect whether the propellant decomposes, and based on the pressure and temperature data, it can determine whether the catalytic igniter is functioning properly and calculate the decomposition efficiency. Furthermore, in this application, during the operation of the catalytic igniter 1, the propellant preheating and catalyst 6 heating can be achieved simultaneously, thereby promoting the efficient decomposition of nitrous oxide, shortening the ignition start-up time, and achieving a rapid response of the catalytic igniter. Further, the catalytic decomposition of nitrous oxide is an exothermic reaction; when the reaction is uneven, heat concentration can occur, leading to sintering of the catalyst bed in the prior art. The electromagnetic heating element 4 in this application can also be used as a flow equalization device to ensure a uniform field, preventing catalyst sintering and allowing for repeated use.
[0061] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.
[0062] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present 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 the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A catalytic igniter, characterized in that, For decomposing the propellant; the catalytic igniter includes: The decomposition chamber, along its axial direction, has opposing first and second ends, and a receiving cavity extending through the decomposition chamber; The injection plate is located at the first end of the decomposition chamber, outside the receiving cavity; An electromagnetic heating element is located within the receiving cavity; a first end of the electromagnetic heating element abuts against the injection plate; the electromagnetic heating element has a first through hole penetrating the electromagnetic heating element along its thickness direction. A heating coil is disposed on the outer wall of the decomposition chamber; A catalyst bed baffle is located within the receiving cavity, with the catalyst bed baffle near the second end of the decomposition chamber; the catalyst bed baffle has a second through hole extending through the catalyst bed baffle along its thickness direction; the thickness direction of the electromagnetic heating element, the thickness direction of the catalyst bed baffle, and the axial direction of the decomposition chamber are aligned. There is a space between the catalyst bed baffle and the electromagnetic heating element, the space being used to accommodate the catalyst. Under the action of the heating coil, the electromagnetic heating element and the decomposition chamber heat the catalyst to the first target temperature; Under the action of the heating coil, the electromagnetic heating element heats the propellant to a second target temperature; after the propellant with the second target temperature comes into contact with the catalyst with the first target temperature, the propellant with the second target temperature is heated to a third target temperature; the third target temperature is greater than or equal to the decomposition threshold temperature of the propellant.
2. The catalytic igniter according to claim 1, characterized in that, Along the axial direction of the decomposition chamber, the decomposition chamber includes a straight cylindrical section and a tail nozzle connected in sequence; the heating coil is disposed on the outer wall of the straight cylindrical section; The straight section includes a first straight section and a second straight section, the second straight section being located between the first straight section and the tail nozzle; the injection disc is disposed at the free end of the first straight section; The height of the receiving cavity located in the first straight cylindrical section is greater than the height of the receiving cavity located in the second straight cylindrical section; The second end of the electromagnetic heating element abuts against the junction of the first straight cylinder portion and the second straight cylinder portion; The catalyst bed baffle and the catalyst are both located in the receiving cavity corresponding to the second straight cylinder section, and the catalyst bed baffle abuts against the junction of the second straight cylinder section and the tail nozzle.
3. The catalytic igniter according to claim 2, characterized in that, The average diameter of the straight cylindrical section is greater than or equal to 10 mm and less than or equal to 30 mm; the length of the straight cylindrical section is greater than or equal to 30 mm and less than or equal to 60 mm.
4. The catalytic igniter according to claim 2, characterized in that, Along the axial direction of the decomposition chamber, the tail nozzle includes a first tail nozzle and a second tail nozzle connected in sequence; the first tail nozzle is connected to the second straight section. Along the direction away from the injection disk, the diameter of the first tail nozzle gradually decreases, and the diameter of the second tail nozzle gradually increases. The first tail nozzle and the second tail nozzle have a throat, the diameter of which is greater than or equal to 0.5 mm and less than or equal to 2 mm.
5. The catalytic igniter according to claim 1, characterized in that, The electromagnetic heating element has a plurality of uniformly distributed first through holes; The diameter of the first through hole is greater than or equal to 0.5 mm and less than or equal to 1 mm; The number of the first through holes is greater than or equal to 20 and less than or equal to 40.
6. The catalytic igniter according to claim 1, characterized in that, The catalyst is a catalyst particle, and the diameter of the second through hole is smaller than the diameter of the catalyst particle; The catalyst bed baffle has a plurality of uniformly distributed second through holes; The thickness of the catalytic bed baffle is greater than or equal to 2 mm and less than or equal to 3 mm.
7. The catalytic igniter according to claim 2, characterized in that, Along the radial direction of the decomposition chamber, the second straight cylindrical portion is provided with a third through hole and a fourth through hole; both the third through hole and the fourth through hole communicate with the receiving cavity; The catalytic igniter also includes: A temperature measuring connector is disposed on the second straight cylindrical portion and communicates with the third through hole; A pressure testing connector is disposed on the second straight cylindrical portion and communicates with the fourth through hole.
8. The catalytic igniter according to claim 1, characterized in that, The catalytic igniter also includes: A seal is located between the injection disc and the first end of the decomposition chamber to achieve a seal between the injection disc and the decomposition chamber.
9. The catalytic igniter according to claim 1, characterized in that, The material of the electromagnetic heating element is the same as that of the decomposition chamber; The materials of the electromagnetic heating element and the decomposition chamber include nickel-iron-niobium alloy.
10. The catalytic igniter according to claim 2, characterized in that, The catalytic igniter also includes: A heat-insulating component is disposed on the outer wall of the straight cylindrical portion; a plurality of spiral grooves are formed on the outer wall of the heat-insulating component, and the heating coil is wound around the outer wall of the heat-insulating component and located within the spiral grooves.