Scramjet hypersonic flame spray gun device and method thereof

Abstract

The device comprises a coaxial stabilizer, a combustion chamber, a coupler and a gun barrel, and the coaxial stabilizer is connected with the rear end of the combustion chamber in a sealed mode and provided with a gun bore pressure measuring pipe, an ignition needle, a fuel needle, a first oxygen input pipe and a second oxygen input pipe. One end of the coupler is in sealed connection with an outlet of the Laval nozzle structure of the combustion chamber, the other end of the coupler is in sealed connection with the gun barrel, a spray gun body is integrally formed, and the interior of the combustion chamber, a central through hole of the coupler and the interior of the gun barrel jointly form a flame channel; a powder feeding needle is arranged on the connector in the radial direction and used for feeding powder into the flame channel of the center through hole and feeding hydrogen and carrier gas into the flame channel of the center through hole. Hydrogen and oxygen are introduced to be subjected to supersonic combustion at the connector, the bore pressure difference and the flame temperature can be further increased, the flame flow speed of a conventional supersonic flame spray gun ranges from 6 Mach to 8 Mach, and the flame flow speed of the supersonic flame spray gun is increased to 10 Mach or above.

Description

Technical Field

[0001] The present invention relates to the field of supersonic flame spraying, and in particular to a method for further increasing the pressure difference and temperature inside and outside the spray gun through scram (supersonic combustion), thereby increasing the flame flow speed. Background Art

[0002] The supersonic flame spraying technology (HVOF) is a thermal spraying method that uses the continuous combustion of oxygen and fuel as heat source and kinetic energy, and uses a special spray gun structure to make the flame flow speed exceed the speed of sound. The supersonic flame spraying technology (HVOF) has the characteristics of high spray particle speed, short heating time, and good suppression of oxidation, phase change and decomposition process of powder materials, so that the prepared coating has the advantages of high bonding strength, high density and stable physical and chemical properties; and because of the high spraying efficiency and wide adaptability to spraying materials, it has been rapidly developed and widely used in the field of surface protection.

[0003] However, after decades of development, the flame jet speed of supersonic flame spray guns in industrial production has reached a bottleneck. Due to limitations such as combustion efficiency, pressure and temperature, the flame speed is generally between 6 and 8 Mach, while the quality and performance of the coating are highly correlated with the flame speed. This has severely restricted the further development of surface coating protection in ultra-high and harsh environment applications such as aerospace, deep-sea development and exploration, and has also severely restricted further breakthroughs in the service life of parts in industrial applications using coating protection.

[0004] Therefore, there is an urgent need for a device and method that can further improve the combustion efficiency, pressure and temperature of the spray gun, thereby further improving the flame velocity of the supersonic oxygen fuel spraying technology (HVOF). Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies of the prior art and provide a scramjc hypersonic flame spray gun device and method thereof, which can further increase the flame flow speed to more than Mach 10 through supersonic combustion.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A scramjet hypersonic flame spray gun device, comprising: a coaxial stabilizer, a combustion chamber, a coupler, and a gun barrel, wherein the front end of the combustion chamber is a Laval nozzle structure, the coaxial stabilizer is sealed and connected to the rear end of the combustion chamber and is provided with a gun chamber pressure measuring tube, an ignition needle, a fuel needle, a No. 1 oxygen input pipe, and a No. 2 oxygen input pipe, and the coupler is axially provided with: a central through hole and an outer water-cooling through hole, one end of the coupler is sealed and connected to the outlet of the Laval nozzle structure of the combustion chamber, and the other end is sealed and connected to the gun barrel, and the whole constitutes a spray gun body, and the inner axial of the gun barrel is The through hole is diffused from the rear end to the front end, and the interior of the combustion chamber, the central through hole and the interior of the barrel together constitute a flame channel; a spray gun housing is provided on the outer sleeve of the combustion chamber, and a barrel housing is provided on the outer sleeve of the barrel; both ends of the spray gun housing are sealed and fixed to the coaxial stabilizer and the coupling, and both ends of the barrel housing are sealed and fixed to the coupling and the end of the barrel, and a water cooling channel is formed between the spray gun housing, the barrel housing and the spray gun body; a powder feeding needle is radially provided on the connector for feeding a carrier gas carrying spray powder and hydrogen into the flame channel of the central through hole.

[0008] In the above technical solution, further, the coaxial stabilizer has multiple through holes inside, which are respectively sealed and connected to the gun barrel pressure measuring tube, ignition needle, fuel needle, No. 1 oxygen input pipe, and No. 2 oxygen input pipe. Among them, the two through holes for installing the fuel needle and No. 1 oxygen input pipe intersect and converge inside the coaxial stabilizer, and merge into one through hole at one end close to the combustion chamber.

[0009] Furthermore, the combustion chamber includes a large space for full combustion at the rear end and a Laval nozzle structure, that is, it is composed of a large space section, a contraction section, a throat, and an expansion section, which can make the flame speed ejected from the combustion chamber outlet exceed the speed of sound.

[0010] Furthermore, a three-way adapter is provided on the connector, one end of which is sealed and connected to the carrier gas tube as the carrier gas inlet, one end is connected to the hydrogen tube as the hydrogen inlet, and one end is connected to the powder feeding needle as the outlet of the carrier gas and hydrogen mixture, and the carrier gas contains spray powder.

[0011] Furthermore, the carrier gas supply pressure is required to be 1.2-1.6 MPa, and the hydrogen supply pressure is required to be 1.2-1.6 MPa.

[0012] Furthermore, the axial through hole of the barrel axis is along the flame spraying direction, and the diameter is maintained after diffusion. The diffusion part includes two diffusion sections with different diffusion angles. The diffusion angle of a section of the barrel close to the connector is larger, and the diffusion angle of a section of the barrel close to the muzzle is smaller.

[0013] Furthermore, the fuel output pressure in the fuel needle is required to be 1.5-2Mpa, the oxygen supply pressure of the No. 1 oxygen input pipe is required to be 1.2-2Mpa, and the oxygen supply pressure of the No. 2 oxygen input pipe is required to be 1.2-2Mpa.

[0014] The working method of the above device comprises the following steps:

[0015] 1) Start the cooling water circulation, fuel supply, carrier gas supply, and oxygen flow supply of No. 1 oxygen input pipe to the gun parameters;

[0016] 2) Execute the ignition procedure, the ignition needle is powered on and ignited, and the fuel supply and the oxygen supply of the No. 1 oxygen input pipe are increased at the same time according to the set fuel-oxygen ratio, so that the flame flow speed of the spray gun reaches Mach 8;

[0017] 3) Open the oxygen supply of No. 2 oxygen input pipe, open the hydrogen supply, so that the hydrogen and carrier gas converge and mix and enter the flame channel of the connector. The flame speed of this section exceeds the speed of sound, belonging to supersonic flame flow. Hydrogen and oxygen burn at super high efficiency in the supersonic flame flow, further increasing the gun chamber pressure and flame temperature, thereby further increasing the speed of the spray gun spray flame flow, so that the flame flow speed is increased to more than Mach 10;

[0018] 4) After the flame is stable, start feeding powder and spraying;

[0019] 5) After the spraying operation is completed, execute the gun stop procedure, first stop the powder delivery, then stop the hydrogen supply and stop the oxygen supply of the No. 2 oxygen input pipe, then stop the fuel supply and the oxygen supply of the No. 1 oxygen input pipe. After the flame is extinguished, open the oxygen supply of the No. 1 oxygen input pipe for a period of time and then close it, and finally turn off the carrier gas.

[0020] The beneficial effects of the present invention are:

[0021] The present invention innovatively adopts a hydrogen-oxygen supersonic combustion method, that is, hydrogen and oxygen undergo an ultra-high efficiency combustion reaction in a supersonic flame flow, which will increase the pressure difference between the gun barrel and the atmospheric pressure to 9-11 Bar, and the flame temperature to about 3300 degrees Celsius, thereby breaking through the conventional supersonic flame spray gun flame flow speed of 6-8 Mach, and increasing the flame flow speed of the supersonic flame spray gun to more than 10 Mach.

[0022] The traditional method of increasing the chamber pressure and flame temperature by increasing the space of the combustion chamber and the supply of fuel and oxygen in the combustion chamber, thereby increasing the flame flow speed, will have the following problems: when the combustion chamber space increases to a certain extent, it is difficult for the fuel and oxygen to be fully burned in the combustion chamber in a short period of time, especially at a position far away from the ignition point, which seriously limits the combustion efficiency and thus limits the flame flow speed of the spray gun. Secondly, the flame flow speed in the combustion section of the combustion chamber is slow. If the excess calorific value is released here, and because the combustion chamber is too large, it affects heat conduction, the water cooling effect is greatly reduced, and the heat load of the combustion chamber is very large, which is likely to cause dangerous situations such as gun explosion.

[0023] The present invention introduces hydrogen and oxygen to cause supersonic combustion at the connector. The supersonic flame flow can quickly transfer heat to the muzzle and convert it into kinetic energy, and can also avoid the problem of excessive heat concentration and excessive heat load in the combustion chamber. At the same time, hydrogen as a reducing gas can effectively curb the generation of brittle phases and improve the quality of the coating. At the same time, the use of a double-diffusion barrel can more quickly release higher flame flow internal energy, convert it into kinetic energy, further increase the flame flow speed, and can also prevent the problem of excessive pressure and temperature concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of a scramjet hypersonic flame spray gun device in an embodiment of the present invention;

[0025] Among them: 1-coaxial stabilizer, 2-combustion chamber, 3-spray gun housing, 4-connector, 5-tee adapter, 6-powder feeding needle, 7-barrel housing, 8-barrel, 9-gun chamber pressure measuring tube, 10-ignition needle, 11-fuel needle, 12-No. 1 oxygen input pipe, 13-No. 2 oxygen input pipe, 14-first fastening sleeve, 15-water cooling inlet channel, 16-water cooling outlet channel, 17-second fastening sleeve, 18-return pipe, 19-third fastening sleeve. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments to make the purpose and effects of the present invention more clearly understood. 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.

[0027] According to a specific embodiment of the present invention, Figure 1 As shown, a schematic diagram of a scramjet hypersonic flame spray gun device is provided, including: a coaxial stabilizer, a combustion chamber, a connector, and a gun barrel, which together constitute a spray gun body, a spray gun housing is also provided outside the combustion chamber, and a gun barrel housing is also provided outside the gun barrel for constructing a water cooling channel;

[0028] The coaxial stabilizer 1 has a plurality of through holes inside, which are respectively sealed and connected to the gun chamber pressure measuring tube 9, the ignition needle 10, the fuel needle 11, the No. 1 oxygen input pipe 12 and the No. 2 oxygen input pipe 13. The main function of the coaxial stabilizer 1 is to ensure stable, safe and efficient combustion in the combustion chamber.

[0029] Furthermore, the two through holes for installing the fuel needle 11 and the No. 1 oxygen input pipe 12 intersect and converge inside the coaxial stabilizer and merge into one through hole at one end close to the combustion chamber.

[0030] Furthermore, the coaxial stabilizer 1 is sealed and fixed to the rear end of the combustion chamber 2 (with the flame spraying direction as the front), and is in close contact with the spray gun housing 3 through the first fastening sleeve 14 and is sealed with a high temperature resistant sealing ring.

[0031] The front end of the combustion chamber 2 is connected to one end of the connector 4 and sealed with a high temperature resistant O-ring. Furthermore, the combustion chamber 2 integrates a sufficient combustion space and a Laval nozzle structure, i.e. Figure 1 It is composed of a large space section (i.e., a section with constant diameter), a contraction section, a throat, and an expansion section, wherein the section with constant diameter is a sufficient combustion space, and the contraction section, throat, and expansion section constitute a Laval nozzle structure. The combustion chamber 2 can make the flame flow speed ejected from its outlet exceed the speed of sound.

[0032] Furthermore, because the temperature (up to about 3300°C) and pressure (9-11Bar) of the combustion system of the spray gun of the present invention are higher than those of ordinary supersonic spray guns, the material of the combustion chamber 2 must be a material with a high melting point and high thermal conductivity. This embodiment uses pure copper material, and the pure copper material is treated with grain refinement and other related processes to improve the tensile strength.

[0033] The spray gun housing 3 is sealedly connected to the coupling 4 and then fastened by a second fastening sleeve 17 .

[0034] The connector 4 is an axisymmetric structure. The axial through hole in the center of the shaft is the flame channel. There are multiple axisymmetric axial through holes near the outside as water cooling channels. There are two axisymmetric through holes in the radial direction as carrier gas and hydrogen channels for placing powder feeding needles.

[0035] Furthermore, one end of the connector 4 is connected to the outlet of the combustion chamber 2 and sealed with a high temperature resistant O-ring, and the other end of the connector 4 is connected to the barrel 8 and sealed with a high temperature resistant O-ring; the interior of the combustion chamber, the axial through hole at the center of the connector shaft, and the interior of the barrel together constitute a flame channel; the main functions of the connector 4 are: first, as a transition system between the combustion chamber 2 and the barrel 8, sharing the combustion task of the combustion chamber 2, being the starting point of supersonic combustion, further increasing the difference between the gun chamber pressure and the atmospheric pressure, further increasing the temperature of the flame, and thus further increasing the flame flow speed; second, as a fixture for fixing the input carrier gas and hydrogen device. Furthermore, the material of the connector 4 must also have the same performance as that of the combustion chamber 2.

[0036] The powder delivery needle 6 is sealed and installed in the radial through hole of the connector 4, and one end is connected to the flame of the axis of the connector 4. The material of this section extending into the flame must have super high wear resistance and melting point, such as tungsten steel. The other end is tightly and sealedly connected to the outlet of the three-way adapter 5. One end of the three-way adapter 5 is sealed and connected to the carrier gas pipe, which is the carrier gas inlet. The spray powder is carried and input by the carrier gas. In this embodiment, the carrier gas is nitrogen with a pressure of 1.2-1.6MPa. The second end is connected to the hydrogen pipe, which is the hydrogen inlet with a pressure of 1.2-1.6MPa. The third end is connected to the powder delivery needle 6, which is the outlet of the nitrogen and hydrogen mixture.

[0037] The two ends of the barrel housing 7 are sealed and connected to the connector 4 and the barrel 8 respectively, and are sealed with a high temperature resistant O-ring, and the connection between the barrel housing and the connector is fastened by a third fastening sleeve 19. Further, the space enclosed by the spray gun housing 3, the coaxial stabilizer 1, the combustion chamber 2, the connector 4, the barrel 8, and the barrel housing 7 forms a water cooling channel for the spray gun. In this embodiment, a return pipe 18 is also provided, and the flow direction of cooling water in the water cooling channel of the spray gun is as follows: water cooling inlet channel 15, the space enclosed by the combustion chamber 2, the coaxial stabilizer 1 and the spray gun housing 3, the cooling water channel of the connector 4, the space enclosed by the barrel 8 and the barrel housing 7, the return pipe 18, and the water cooling outlet channel 16.

[0038] In this example, the gun barrel 8 is an axisymmetric hollow structure, the rear end of which is sealed and connected to the connector 4. The through hole in the axial direction of the gun barrel 8 is diffused along the direction of the flame spraying, and the diameter of the through hole is getting larger and larger, and remains unchanged when the diameter reaches the designed value. Figure 1 As shown, the two sections of the gun barrel 8 from left to right adopt two different diffusion angles. The left section has a larger diffusion angle, which can quickly release the internal energy of the flame flow and convert it into kinetic energy to prevent the pressure and temperature in the supersonic stage from being too concentrated and high; the right section has a smaller diffusion angle, which can more smoothly release the internal energy of the flame flow and continuously increase the speed of the flame flow. Compared with the existing supersonic spray gun barrel, the diffusion tube structure of the gun barrel 8 can more quickly release higher flame flow internal energy, convert it into kinetic energy, and further increase the flame flow speed.

[0039] The gun chamber pressure measuring tube 9 is sealed and installed in a through hole of the coaxial stabilizer 1. The material is pure copper. The main function is to monitor the internal pressure of the spray gun.

[0040] The ignition needle 10 is sealed and installed in a through hole of the coaxial stabilizer 1. Its main function is to release the arc for ignition. An ignition needle commonly used in the market can be used.

[0041] The fuel needle 11 is sealed and installed in the through hole at the axis center of the coaxial stabilizer 1, and its outlet is also in the through hole at the axis center of the coaxial stabilizer 1. The fuel used in this embodiment is aviation kerosene, and the kerosene pressure is 1.5-2Mpa.

[0042] The No. 1 oxygen input pipe 12 is installed in the through hole intersecting with the axial through hole of the coaxial stabilizer 1, and is a conventional combustion oxygen supply pipe. The oxygen input pressure is in the range of 1.2-2 MPa, preferably in the range of 1.5-1.8 MPa.

[0043] Furthermore, the No. 1 oxygen input pipe 12 is transporting oxygen during the entire ignition and spraying process, and the flow rates of oxygen and aviation kerosene maintain a constant fuel-oxygen ratio to ensure full combustion of the fuel.

[0044] Furthermore, the oxygen inputted by the No. 1 oxygen input pipe 12 also has the function of atomizing aviation kerosene.

[0045] The No. 2 oxygen input pipe 13 is sealed and installed in a through hole of the coaxial stabilizer 1. Its main function is to further input oxygen and increase the oxygen content around the flame core. The oxygen input pressure is in the range of 1.2-2 MPa, preferably in the range of 1.5-1.8 MPa.

[0046] In the above scheme, the clamping sleeve is used to tighten the contact between the coaxial stabilizer, the combustion chamber, the spray gun housing, the connector or the barrel housing by screwing, so as to ensure that they are not moved by the pressure inside the gun.

[0047] According to a specific embodiment of the present invention, the working method of the above-mentioned scramjets includes the following:

[0048] 1. Start the cooling water circulation, start the aviation kerosene supply, start the nitrogen supply, and start the oxygen flow supply of No. 1 oxygen pipe input pipe 12 to the point gun parameters;

[0049] 2. Execute the ignition procedure, ignition needle 10 is powered on and ignited, and the aviation kerosene supply and the oxygen supply of No. 1 oxygen input pipe 12 are increased at the same time according to a certain fuel-oxygen ratio, so that the flame flow speed of the spray gun reaches the conventional 8 Mach.

[0050] 3. Open the oxygen supply of No. 2 oxygen input pipe 13, open the hydrogen supply, and make the hydrogen and carrier gas converge and mix together to enter the flame space of the connector 4. The flame speed of this section exceeds the speed of sound, which belongs to the supersonic flame flow. Hydrogen and oxygen burn with super high efficiency in the supersonic flame flow, further increasing the gun barrel pressure and flame temperature, so that the pressure difference between the gun barrel and the atmospheric pressure increases from the conventional 6-8Bar to 9-11Bar, and the flame temperature increases from the conventional 3000℃ to about 3300℃, thereby further increasing the speed of the spray gun spraying flame, and the flame speed is increased to more than Mach 10.

[0051] 4. After the flame stabilizes, start feeding powder and spraying.

[0052] 5. After the spraying operation is completed, execute the gun stop procedure, first stop the powder feeding, then stop the hydrogen supply and stop the oxygen supply of No. 2 oxygen input pipe 13, then stop the aviation kerosene supply and the oxygen supply of No. 1 oxygen input pipe 12, and after the flame is extinguished, open the oxygen supply of No. 1 oxygen input pipe 12 for a period of time and then close it, and finally close the nitrogen.

Claims

1. A scramjet hypersonic flame spray gun device, characterized in that: include: A coaxial stabilizer, a combustion chamber, a connector, and a gun barrel. The front end of the combustion chamber is a Laval nozzle structure. The coaxial stabilizer is sealed and connected to the rear end of the combustion chamber and is provided with a gun chamber pressure measuring tube, an ignition needle, a fuel needle, a No. 1 oxygen input pipe, and a No. 2 oxygen input pipe. The connector is axially provided with: a central through hole and an outer water-cooling through hole. One end of the connector is sealed and connected to the outlet of the Laval nozzle structure of the combustion chamber, and the other end is sealed and connected to the gun barrel, forming a spray gun body as a whole. The axial through hole inside the gun barrel is diffused from the rear end to the front end. The interior of the combustion chamber, the central through hole, and the interior of the gun barrel together constitute a flame channel; a spray gun housing is provided on the outer sleeve of the combustion chamber, and a gun barrel housing is provided on the outer sleeve of the gun barrel. Both ends of the spray gun housing are sealed and fixed to the coaxial stabilizer and the coupling, and both ends of the gun barrel housing are sealed and fixed to the coupling and the end of the gun barrel. A water-cooling channel is formed between the spray gun housing, the gun barrel housing, and the spray gun body; a powder feeding needle is radially provided on the connector for feeding a carrier gas carrying spray powder and hydrogen into the flame channel of the central through hole.

2. The scramjets according to claim 1, characterized in that: The coaxial stabilizer has multiple through holes inside, which are respectively sealed and connected to the gun barrel pressure measuring tube, ignition needle, fuel needle, No. 1 oxygen input pipe, and No. 2 oxygen input pipe. Among them, the two through holes for installing the fuel needle and No. 1 oxygen input pipe intersect and converge inside the coaxial stabilizer and merge into one through hole at one end close to the combustion chamber.

3. The scramjets according to claim 1, characterized in that: The combustion chamber comprises a large space for full combustion at the rear end and a Laval nozzle structure, namely, it is composed of a large space section, a contraction section, a throat section and an expansion section, which can make the flame speed ejected from the combustion chamber outlet exceed the speed of sound.

4. The scramjets of claim 1, wherein: A three-way adapter is also provided on the connector, one end of which is sealed and connected to the carrier gas pipe as the carrier gas inlet, one end is connected to the hydrogen pipe as the hydrogen inlet, and one end is connected to the powder delivery needle as the outlet of the carrier gas and hydrogen mixture, and the carrier gas contains spray powder.

5. The scramjets of claim 4, characterized in that: The carrier gas supply pressure is required to be 1.2-1.6MPa, and the hydrogen supply pressure is required to be 1.2-1.6Mpa.

6. The scramjets of claim 1, characterized in that: The axial through hole of the barrel axis is along the flame spraying direction, and is in a shape of maintaining the diameter after diffusion. The diffusion part includes two diffusion sections with different diffusion angles. The diffusion angle of a section of the barrel close to the connector is larger, and the diffusion angle of a section of the barrel close to the muzzle is smaller.

7. The scramjets of claim 1, characterized in that: The fuel output pressure in the fuel needle is required to be 1.5-2Mpa, the oxygen supply pressure of the No. 1 oxygen input pipe is required to be 1.2-2Mpa, and the oxygen supply pressure of the No. 2 oxygen input pipe is required to be 1.2-2Mpa.

8. The working method of the device according to any one of claims 1 to 7, characterized in that: These include: 1) Start the cooling water circulation, fuel supply, carrier gas supply, and oxygen flow supply of No. 1 oxygen input pipe to the gun parameters; 2) Execute the ignition procedure, the ignition needle is powered on and ignited, and the fuel supply and the oxygen supply of the No. 1 oxygen input pipe are increased at the same time according to the set fuel-oxygen ratio, so that the flame flow speed of the spray gun reaches Mach 8; 3) Open the oxygen supply of No. 2 oxygen input pipe, open the hydrogen supply, so that the hydrogen and carrier gas converge and mix and enter the flame channel of the connector. The flame speed of this section exceeds the speed of sound, belonging to supersonic flame flow. Hydrogen and oxygen burn at super high efficiency in the supersonic flame flow, further increasing the gun chamber pressure and flame temperature, thereby further increasing the speed of the spray gun spray flame flow, so that the flame flow speed is increased to more than Mach 10; 4) After the flame is stable, start feeding powder and spraying; 5) After the spraying operation is completed, execute the gun stop procedure, first stop the powder delivery, then stop the hydrogen supply and stop the oxygen supply of the No. 2 oxygen input pipe, then stop the fuel supply and the oxygen supply of the No. 1 oxygen input pipe. After the flame is extinguished, open the oxygen supply of the No. 1 oxygen input pipe for a period of time and then close it, and finally turn off the carrier gas.

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