A catalytic ignition small thruster and a two-stage combustion organization method thereof

Abstract

The present invention discloses a catalytic ignition small thruster and a two-stage combustion organization method, including arranging a catalyst in a first cavity to realize catalytic combustion of a mixed gas and coaxial diffusion combustion in a second cavity, fuel and oxidant forming a uniform mixed gas in the mixing cavity and entering the first cavity, high-temperature gas generated by the catalytic reaction of the catalyst in the first cavity enters the thrust chamber of the second cavity, and contacts with the gas entering the second cavity from the central air intake pipe for further combustion, and the high-temperature gas generated by the combustion in the combustion chamber formed in the second cavity is ejected from the nozzle to generate thrust, wherein the mixing state of the mixed gas entering the mixed gas cavity is determined by determining the catalytic performance of the catalyst, and a coaxial anti-diffusion flame or a coaxial diffusion flame is generated in the second cavity according to different mixing states. The thruster and the two-stage combustion organization method provided by the present invention can flexibly adjust the combustion organization mode, and are more suitable for the combustion propulsion mode of a micro-thruster.

Description

Technical Field

[0001] The invention relates to the technical field of micro thrusters, and in particular to a catalytic ignition small thruster and a two-stage combustion organization method thereof. Background Art

[0002] Micro-combustors play an important role in micro-propulsion systems and generators. Currently, the combustion organization methods of the thrust chamber of micro-combustors mainly include stratified combustion organization method, graded swirl combustion organization method and direct injection in cylinder, etc. However, the complex injection devices required by these combustion organization methods are not suitable for small-sized micro-thruster systems.

[0003] At the same time, the combustion process of micro-burners has the characteristics of relatively large flame surface volume ratio, short residence time, and difficulty in ignition. In a confined space, there is a large pressure gradient along the axial direction of the jet, which leads to the formation of reflux around the wall, making the combustion process more complicated and more prone to combustion instability.

[0004] Therefore, in micro-scale power systems, conventional combustion methods often face problems such as unstable combustion or difficulty in sustained combustion. Summary of the invention

[0005] The purpose of the present invention is to provide a catalytic ignition small thruster and a two-stage combustion organization method thereof, so as to solve the technical problems in the prior art that conventional combustion means often face unstable combustion or difficulty in continuous combustion.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions:

[0007] A catalytic ignition small thruster comprises a first cavity and a second cavity connected coaxially in sequence, wherein a nozzle is arranged at an end of the second cavity away from the first cavity.

[0008] The front end of the first cavity is connected to a gas mixing cavity, and the gas fuel and the gaseous oxidant entering the gas mixing cavity are mixed in the gas mixing cavity to form a mixed gas, and then transported to the first cavity;

[0009] A catalyst is arranged in the first cavity, and the mixed gas undergoes a catalytic combustion reaction by contacting with the catalyst in the first cavity, and the generated high-temperature gas enters the second cavity;

[0010] The high-temperature gas entering the second cavity burns after contacting the gaseous oxidant input into the second cavity and is ejected from the nozzle to generate thrust.

[0011] As a preferred solution of the present invention, a central air intake pipe is arranged in the first cavity and along the axial direction of the first cavity, one end of the central air intake pipe extends to the mixing cavity and is connected to the air intake assembly arranged on the mixing cavity, and the other end extends to the connection between the first cavity and the second cavity.

[0012] As a preferred solution of the present invention, the diameter of the first cavity is greater than the diameter of the second cavity, and the first cavity is connected to the second cavity through a tapering tube.

[0013] As a preferred solution of the present invention, the cavity diameter of the tapering tube gradually decreases toward the second cavity.

[0014] As a preferred solution of the present invention, fire-blocking gaskets are provided at both ends of the catalyst in the first cavity, and the surface of the fire-blocking gasket is distributed with perforations, and the aperture of the perforations is smaller than the gas extinguishing diameter in the first cavity, so as to prevent the burning mixed gas in the first cavity from entering the mixed gas cavity.

[0015] As a preferred embodiment of the present invention, the catalyst comprises a honeycomb ceramic-supported platinum catalyst.

[0016] The present invention provides a two-stage combustion organization method according to the catalytic ignition small thruster, comprising the following steps:

[0017] Step 100, obtaining the catalytic performance of the catalyst and determining the mixing state of the mixed gas entering the mixed gas chamber;

[0018] The mixture state includes rich fuel mixture and lean fuel mixture;

[0019] Step 200, the mixed gas is sent into the first cavity, and a catalytic reaction is carried out by the catalyst. After a set time, a gaseous oxidant or a gaseous fuel is sent into the thrust chamber through the intake assembly and the central intake pipe, and meets and burns with the high-temperature gas sent from the first cavity to the second cavity;

[0020] If the mixed state of the mixed gas is a fuel-rich mixture, a coaxial counter-diffusion combustion flame is formed in the second cavity, and once a stable flame is formed, the supply of oxidant to the first cavity is immediately stopped;

[0021] If the mixed state of the mixed gas is a lean-burn mixture, a coaxial diffusion combustion flame is formed in the second cavity, and once a stable flame is formed, the fuel is immediately stopped from being delivered to the first cavity;

[0022] Step 300: High-temperature gas generated by combustion is ejected at high speed through a nozzle to generate thrust.

[0023] As a preferred solution of the present invention, in step 100, it is necessary to ensure that the gas fuel concentration of the mixed gas in the mixing chamber is outside the flammable range.

[0024] As a preferred embodiment of the present invention, in step 200, after the high temperature gas catalytically reacted in the first cavity contacts and ignites with other oxidants or gaseous fuels transported to the second cavity;

[0025] If the second cavity is a coaxial diffusion combustion flame, immediately stop delivering gas fuel to the first cavity;

[0026] If the second cavity contains a coaxial counter-diffusion combustion flame, the delivery of the gaseous oxidant into the first cavity is immediately stopped.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention can be used for thrusters using various fuels such as hydrogen or other gaseous hydrocarbon fuels and gaseous oxidants.

[0029] The high-temperature gas formed by the primary catalytic combustion in the present invention can be used as an ignition source for the combustion of other fuels. The catalytic ignition device is simpler and the ignition process is safer.

[0030] The present invention is simple and flexible to use and has strong applicability. The combustion organization mode can be flexibly adjusted by changing the relative content of the gas at the air inlet, the gas type and a suitable catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0032] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0033] Figure 2 It is a schematic structural diagram of a fire-blocking gasket according to an embodiment of the present invention.

[0034] The numbers in the figure represent the following:

[0035] 10-first cavity; 20-second cavity; 30-nozzle; 40-mixing cavity; 50-catalyst; 60-central air intake pipe; 70-intake assembly; 80-gradient tube; 90-fire-blocking gasket; 91-perforation. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] like Figure 1 As shown, the present invention provides a catalytic ignition small thruster comprising a first cavity 10 and a second cavity 20 connected coaxially in sequence, and a nozzle 30 is arranged at the end of the second cavity 20 away from the first cavity 10;

[0038] The front end of the first cavity 10 is connected to a gas mixing cavity 40, and the gas fuel and the gaseous oxidant entering the gas mixing cavity 40 are mixed in the gas mixing cavity 40 to form a mixed gas, which is then transported to the first cavity 10;

[0039] A catalyst 50 is disposed in the first cavity 10. The mixed gas catalyzed by the catalyst 50 is ignited in the first cavity 10, and the generated high-temperature gas enters the second cavity 20.

[0040] The high-temperature gas entering the second cavity 20 burns after contacting the gaseous oxidant input into the second cavity 20 and is ejected from the nozzle 30 to generate thrust.

[0041] The thruster provided in this embodiment can use hydrogen, oxygen or other gaseous hydrocarbon fuels in combination with a gaseous oxidant as fuel to perform two-stage combustion to provide thrust.

[0042] In this embodiment, the first cavity 10 and the second cavity 20 are coaxially connected, and the second cavity 20 is used as a thrust chamber. The central air intake pipe 60 arranged in the first cavity 10 and the second cavity 20 is used for air intake, which can reduce the setting of the fuel pipeline structure around the thruster and make the overall volume smaller.

[0043] The high-temperature gas formed by the primary catalytic combustion in the first cavity 10 can be used as an ignition source for the combustion of other fuels. The catalytic ignition device is simpler and the ignition process is safer.

[0044] This embodiment is simple and flexible to use and has strong applicability. By changing the relative content of the gas at the air inlet, the type of gas and a suitable catalyst 50, the combustion organization mode can be flexibly adjusted.

[0045] A central air intake pipe 60 is arranged in the first cavity 10 and along the axial direction of the first cavity 10, one end of the central air intake pipe 60 extends to the mixing cavity 40, and is connected to the air intake assembly 70 arranged on the mixing cavity 40, specifically an air intake pipe with a valve structure, and the other end extends to the connection between the first cavity 10 and the second cavity 20.

[0046] The diameter of the first cavity 10 is greater than that of the second cavity 20 , and the first cavity 10 is connected to the second cavity 20 via a tapering tube 80 , and the cavity diameter of the tapering tube 80 gradually decreases toward the second cavity 20 .

[0047] In this embodiment, in order to prevent the flame of the mixed gas burning in the catalyst chamber from entering the mixed gas cavity, fire-blocking gaskets 90 are provided at both ends of the catalyst in the first cavity.

[0048] Specifically, Figure 2 As shown, the surface of the fire-blocking gasket 90 is distributed with perforations 91 , the aperture of which is smaller than the gas extinguishing diameter in the first cavity 10 , so as to prevent the burning mixed gas in the first cavity 10 from entering the gas mixing cavity 40 .

[0049] The catalyst 50 in this embodiment is preferably a honeycomb ceramic-supported platinum catalyst.

[0050] Furthermore, in the present embodiment 4, if the second cavity 20 adopts coaxial counter-diffusion combustion in the secondary diffusion combustion organization mode in the thrust chamber, and the gas entering the thrust chamber from the first cavity 10 as the catalyst chamber is mainly a fuel with a lower density such as hydrogen, it will take away more heat from the thrust chamber wall, which helps to prevent the generation of local high temperature in the thrust chamber.

[0051] This embodiment provides a two-stage combustion organization method implemented according to the two-stage combustion organization device of the catalytic ignition small thruster, comprising the following steps:

[0052] Step 100, obtaining the catalytic performance of the catalyst and determining the mixing state of the mixed gas entering the mixed gas chamber;

[0053] The mixture state includes rich fuel mixture and lean fuel mixture;

[0054] Step 200, the mixed gas is sent into the first cavity, and a catalytic reaction is carried out by the catalyst. After a set time, a gaseous oxidant or a gaseous fuel is sent to the thrust chamber through the intake assembly and the central intake pipe, and meets and burns with the high-temperature gas transported from the first cavity to the second cavity;

[0055] If the mixed state of the mixed gas is a fuel-rich mixture, a coaxial counter-diffusion combustion flame is formed in the second cavity, and once a stable flame is formed, the supply of oxidant to the first cavity is immediately stopped;

[0056] If the mixed state of the mixed gas is a lean-burn mixture, a coaxial diffusion combustion flame is formed in the second cavity, and once a stable flame is formed, the supply of oxidant to the first cavity is immediately stopped;

[0057] Step 300: High-temperature gas generated by combustion is ejected at high speed through a nozzle to generate thrust.

[0058] In step 100, it is necessary to ensure that the gas fuel concentration of the mixed gas in the mixing chamber is outside the flammable range.

[0059] A honeycomb ceramic platinum-supported catalyst is placed in the second cavity, anti-flashback gaskets are installed before and after the catalyst, and an air inlet A and an air inlet B are provided on the mixing cavity to connect to the mixing cavity, which are not marked in the figure.

[0060] If the catalyst has a better catalytic effect under rich fuel conditions:

[0061] The gaseous fuel enters the mixing chamber through the air inlet A. About 2 seconds later, an appropriate amount of gaseous oxidant enters the premixing chamber (mixing chamber) through the air inlet B and is fully mixed with the gaseous fuel introduced previously to form a fuel-rich mixture, and the fuel concentration is ensured to be outside the gas phase flammable range; the fuel-rich mixture in the mixing chamber enters the first chamber (catalytic chamber) and contacts with the catalyst to undergo a catalytic reaction. About 10 seconds later, another part of the gaseous oxidant enters the second chamber (thrust chamber) through the air intake assembly and the central air intake pipe. The gaseous oxidant introduced by the air intake assembly meets and burns with the high-temperature fuel-rich gas entering the combustion chamber from the catalyst chamber, forming a coaxial counter-diffusion flame.

[0062] If reverse diffusion combustion is adopted in the secondary diffusion combustion organization mode in the thrust chamber, and the gas entering the thrust chamber from the catalyst chamber is mainly a fuel with lower density such as hydrogen, it will take away more heat from the thrust chamber wall, which will help prevent the generation of local high temperature.

[0063] If the catalyst has a better catalytic effect under lean combustion conditions:

[0064] The gaseous fuel enters the mixing chamber through the air inlet A. About 2 seconds later, an appropriate amount of gaseous oxidant enters the premixing chamber (mixing chamber) through the air inlet B and is fully mixed with the gaseous fuel introduced previously to form a lean fuel mixture, while ensuring that the fuel concentration is outside the flammable range.

[0065] The lean fuel mixture in the mixing cavity enters the first cavity (catalytic chamber) and contacts the catalyst to produce a catalytic reaction. About 10 seconds later, another part of the gas fuel enters the second cavity (thrust chamber) through the intake assembly and the central intake pipe. The gas fuel introduced by the intake assembly meets and burns with the high-temperature gaseous oxidant entering the thrust chamber from the catalyst chamber, forming a coaxial diffusion flame.

[0066] If diffusion combustion is adopted in the secondary diffusion combustion organization mode inside the thrust chamber, the research conclusions in recent years on the stability characteristics of micro-laterally restricted coaxial diffusion combustion can directly provide a theoretical basis for the design of the thrust chamber size.

[0067] The high-temperature gases produced by combustion are ejected at high speed through the nozzle to generate thrust.

[0068] In step 200, after the high temperature gas catalytically reacted in the first chamber contacts and ignites with other oxidants or gaseous fuels transported to the second chamber:

[0069] If the second cavity is a coaxial diffusion combustion flame, immediately stop delivering gas fuel to the first cavity;

[0070] If the second cavity contains a coaxial counter-diffusion combustion flame, the delivery of the gaseous oxidant into the first cavity is immediately stopped.

[0071] It can effectively stop the catalytic combustion in the first cavity and prevent the long-term high temperature from affecting the activity of the catalyst.

[0072] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A catalytic ignition small thruster, comprising a first cavity (10) and a second cavity (20) connected coaxially in sequence, wherein a nozzle (30) is arranged at an end of the second cavity (20) away from the first cavity (10), characterized in that: The front end of the first cavity (10) is connected to a gas mixing cavity (40), and the gaseous fuel and the gaseous oxidant entering the gas mixing cavity (40) are mixed in the gas mixing cavity (40) to form a mixed gas, which is then transported to the first cavity (10); A catalyst (50) is arranged in the first cavity (10), and the mixed gas in the first cavity (10) undergoes a catalytic combustion reaction by contacting the catalyst (50), and the generated high-temperature gas enters the second cavity (20); The high-temperature gas entering the second cavity (20) burns after contacting the gaseous oxidant input into the second cavity (20) and is ejected from the nozzle (30) to generate thrust; A central air intake pipe (60) is arranged in the first cavity (10) and along the axial direction of the first cavity (10), one end of the central air intake pipe (60) extends to the gas mixing cavity (40) and is connected to an air intake assembly (70) arranged on the gas mixing cavity (40), and the other end extends to the connection between the first cavity (10) and the second cavity (20); The diameter of the first cavity (10) is greater than the diameter of the second cavity (20), and the first cavity (10) is connected to the second cavity (20) via a tapering tube (80).

2. A catalytic ignition small thruster according to claim 1, characterized in that: The cavity diameter of the gradually tapering tube (80) gradually decreases toward the second cavity (20).

3. A catalytic ignition small thruster according to claim 2, characterized in that: Fire-blocking gaskets (90) are provided at both ends of the catalyst (50) in the first cavity (10); the surface of the fire-blocking gasket (90) is provided with perforations (91); the aperture of the perforations (91) is smaller than the gas extinguishing diameter in the first cavity (10), and is used to prevent the burning mixed gas in the first cavity (10) from entering the mixed gas cavity (40).

4. A catalytic ignition small thruster according to claim 1, characterized in that: The catalyst (50) comprises a honeycomb ceramic-supported platinum catalyst.

5. A two-stage combustion organization method for a catalytic ignition small thruster according to any one of claims 1 to 4, characterized in that: The steps include: Step 100, obtaining the catalytic performance of the catalyst and determining the mixing state of the mixed gas entering the mixed gas chamber; The mixture state includes rich fuel mixture and lean fuel mixture; Step 200, the mixed gas is sent into the first cavity, and a catalytic reaction is carried out by the catalyst. After a set time, a gaseous oxidant or a gaseous fuel is sent to the thrust chamber formed by the second cavity through the intake assembly and the central intake pipe, and meets and burns with the high-temperature gas sent from the first cavity to the second cavity; If the mixed state of the mixed gas is a fuel-rich mixture, a coaxial counter-diffusion combustion flame is formed in the second cavity; If the mixed state of the mixed gas is a lean-burn mixture, a coaxial diffusion combustion flame is formed in the second cavity; Step 300: High-temperature gas generated by combustion is ejected at high speed through a nozzle to generate thrust.

6. A two-stage combustion organization method for a catalytic ignition small thruster according to claim 5, characterized in that: In step 100, it is necessary to ensure that the gas fuel concentration of the mixed gas in the mixing chamber is outside the flammable range.

7. A two-stage combustion organization method for a catalytic ignition small thruster according to claim 6, characterized in that: In step 200, after the high temperature gas catalytically reacted in the first chamber contacts and ignites with other oxidants or gaseous fuels transported to the second chamber; If the second cavity is a coaxial diffusion combustion flame, immediately stop delivering gas fuel to the first cavity; If the second cavity contains a coaxial counter-diffusion combustion flame, the delivery of the gaseous oxidant into the first cavity is immediately stopped.

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