A super-combustion hypersonic flame spray gun device and method thereof

Abstract

The application discloses a super-combustion hypersonic flame spray gun device and a method thereof, and the device comprises a coaxial stabilizer, a combustion chamber, a coupler and a gun barrel, the coaxial stabilizer is in sealing connection with the rear end of the combustion chamber and is provided with a bore pressure measuring pipe, an ignition needle, a fuel needle, a No.1 oxygen input pipe and a No.2 oxygen input pipe, one end of the coupler is in sealing connection with the outlet of a Laval nozzle structure of the combustion chamber, the other end of the coupler is in sealing connection with the gun barrel, and the whole constitutes a spray gun body, the inside of the combustion chamber, the center through hole of the coupler and the inside of the gun barrel jointly constitute a flame channel, and a powder feeding needle is arranged on the coupler in a radial direction and used for feeding powder into the flame channel of the center through hole and feeding hydrogen and carrier gas. The hydrogen and the oxygen are introduced to generate supersonic combustion at the coupler, the bore pressure difference and the flame temperature can be further improved, and the conventional supersonic flame spray gun flame speed of 6-8 Mach can be broken through, and the flame speed of the supersonic flame spray gun is improved to more than 10 Mach.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high velocity oxygen fuel (HVOF) spraying, and in particular to a hypersonic flame spraying device and method for further increasing the pressure difference and temperature inside and outside the spray gun by hyper-combustion (supersonic combustion) and thereby increasing the flame speed. BACKGROUND

[0002] High velocity oxygen fuel (HVOF) spraying is a thermal spraying method in which continuous combustion of oxygen and fuel is used as a heat source and kinetic energy, and a special spray gun structure is used to make the flame speed exceed the speed of sound. Because of the high particle velocity, short heating time, good inhibition of oxidation, phase change and decomposition of powder materials, and other characteristics, high velocity oxygen fuel (HVOF) spraying has the advantages of high bonding strength, high density and stable physical and chemical properties of the prepared coating. Because of the high spraying efficiency and wide range of suitable 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 the high velocity oxygen fuel (HVOF) spray gun in industrial production has reached a bottleneck. Due to limitations in combustion efficiency, pressure and temperature, the flame speed is generally 6-8 Mach, and the quality and performance of the coating have a considerable correlation with the flame speed, which seriously restricts the further development of surface coating protection in aerospace, deep sea exploration and other ultra-high and harsh environments, and also seriously restricts the further breakthrough of coating protection in industrial applications for the service life of parts.

[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 increasing the flame speed of high velocity oxygen fuel (HVOF) spraying. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provides a hyper-combustion hypersonic flame spraying device and method that can further increase the flame speed by supersonic combustion to more than 10 Mach.

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

[0007] The super-burning hypersonic flame spray gun device comprises a coaxial stabilizer, a combustion chamber, a coupling, a gun barrel, the front end of the combustion chamber is a Laval nozzle structure, the coaxial stabilizer is sealingly connected with the rear end of the combustion chamber and is provided with a bore pressure measuring pipe, an ignition needle, a fuel needle, a No. 1 oxygen input pipe and a No. 2 oxygen input pipe, a central through hole and an outer water cooling through hole are arranged on the coupling in the axial direction, one end of the coupling is sealingly connected with the outlet of the Laval nozzle structure of the combustion chamber, the other end is sealingly connected with the gun barrel, and the whole constitutes a spray gun body, the axial through hole of the gun barrel is in a diverging shape from the rear end to the front end, and the inside of the combustion chamber, the central through hole and the inside of the gun barrel jointly constitute a flame channel, a spray gun shell is arranged on the outside of the combustion chamber, a gun barrel shell is arranged on the outside of the gun barrel, the two ends of the spray gun shell are sealingly fixed with the coaxial stabilizer and the coupling, the two ends of the gun barrel shell are sealingly fixed with the coupling and the end of the gun barrel, and the water cooling channel is formed between the spray gun shell, the gun barrel shell and the spray gun body, and a powder feeding needle is arranged on the coupling in the radial direction for feeding the carrier gas carrying the spraying powder and hydrogen into the flame channel of the central through hole.

[0008] In the technical scheme, further, the coaxial stabilizer has multiple through holes inside, which are sealingly connected with the bore pressure measuring pipe, the ignition needle, the fuel needle, the No. 1 oxygen input pipe and the No. 2 oxygen input pipe respectively, wherein the two through holes for mounting the fuel needle and the No. 1 oxygen input pipe intersect and converge inside the coaxial stabilizer and are combined into one through hole at the end close to the combustion chamber.

[0009] Further, the combustion chamber comprises a sufficient combustion large space at the rear end and a Laval nozzle structure, i.e. a large space section, a contraction section, a throat and an expansion section, which can make the flame speed ejected from the outlet of the combustion chamber exceed the speed of sound.

[0010] Further, a three-way adapter is arranged on the coupling, one end of which is sealingly connected with the carrier gas pipe for the carrier gas inlet, one end is connected with the hydrogen pipe for the hydrogen inlet, and one end is connected with the powder feeding needle for the outlet of the carrier gas and hydrogen mixed gas, and the carrier gas contains spraying powder.

[0011] Further, 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] Further, the axial through hole of the gun barrel along the flame ejection direction is in a diverging rear straight diameter maintaining shape, the diverging part comprises two diverging sections with different diverging angles, the diverging angle of the section of the gun barrel close to the coupling is larger, and the diverging angle of the section of the gun barrel close to the muzzle is smaller.

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

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

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

[0016] 2) Perform the ignition program, power on the ignition needle to ignite, and simultaneously increase the fuel supply amount and the oxygen supply amount of the No. 1 oxygen input pipe according to the set fuel-oxygen ratio, so that the jet flow speed of the spray gun reaches 8 Mach;

[0017] 3) Start the oxygen supply of the No. 2 oxygen input pipe, start the hydrogen supply, and make the hydrogen and the carrier gas converge and mix together into the flame passage of the connector, the flame speed of this section exceeds the speed of sound and belongs to supersonic jet flow, the hydrogen and the oxygen have a super-high-efficiency combustion in the supersonic jet flow, which further increases the bore pressure and the flame temperature, thereby further improving the jet flow speed of the spray gun, so that the jet flow speed is increased to more than 10 Mach;

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

[0019] 5) After the spraying operation is completed, perform the stop gun program, stop the powder feeding first, then stop the hydrogen supply and 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, and after the flame is extinguished, start the oxygen supply of the No. 1 oxygen input pipe for a period of time and then stop it, and finally stop the carrier gas.

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

[0021] The present application innovatively adopts a hydrogen-oxygen supersonic combustion mode, that is, the hydrogen and the oxygen have a super-high-efficiency combustion reaction in the supersonic jet flow, which increases the pressure difference between the bore and the atmospheric pressure to 9-11 Bar and increases the flame temperature to about 3300 degrees Celsius, thereby breaking through the speed of 6-8 Mach of the conventional supersonic flame spray gun and increasing the jet flow speed of the supersonic flame spray gun to more than 10 Mach.

[0022] The conventional method of increasing the space of the combustion chamber and increasing the supply of fuel and oxygen in the combustion chamber to increase the bore pressure and the flame temperature and thereby increase the jet flow speed has the following problems: when the space of the combustion chamber is increased to a certain extent, the fuel and the oxygen are difficult to fully burn in the combustion chamber within a short time, especially at positions far away from the ignition point, which seriously limits the combustion efficiency and thereby limits the jet flow speed of the spray gun. Secondly, the jet flow speed in the combustion section of the combustion chamber is slow, and if the excess heat value is released here, the heat conduction is affected due to the large combustion chamber, the water cooling effect is greatly reduced, the heat load of the combustion chamber is very large, and dangerous situations such as gun explosion may occur.

[0023] The present application introduces hydrogen and oxygen to occur supersonic combustion at the coupler, the supersonic flame flow can quickly transfer heat to the muzzle, and the heat is converted into kinetic energy, which can avoid the problems of excessive heat concentration and excessive thermal load of the combustion chamber, and hydrogen as a reducing gas can effectively suppress the generation of brittle phase and improve the quality of the coating. Meanwhile, the double diffusion type gun barrel can release higher internal energy of the flame flow more quickly, convert it into kinetic energy, further improve the flame flow speed, and also prevent the problems of excessive concentration of pressure and temperature. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a schematic diagram of a supersonic flame spray gun device in an embodiment of the present application;

[0025] Among them: 1-coaxial stabilizer, 2-combustion chamber, 3-spray gun shell, 4-coupler, 5-three-way adapter, 6-powder feeding needle, 7-gun barrel shell, 8-gun barrel, 9-bore pressure measuring tube, 10-ignition needle, 11-fuel needle, 12-1 oxygen input pipe, 13-2 oxygen input pipe, 14-first fastening sleeve, 15-water cooling inlet channel, 16-water cooling outlet channel, 17-second fastening sleeve, 18-backwater pipe, 19-third fastening sleeve. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with the drawings and specific embodiments, so that the purpose and effect of the present application become more clear. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0027] According to a specific embodiment of the present application, as shown in Figure 1 A schematic diagram of a supersonic flame spray gun device is provided, which comprises a coaxial stabilizer, a combustion chamber, a coupler, and a gun barrel, and the whole constitutes a spray gun body. A spray gun shell is further sleeved outside the combustion chamber, and a gun barrel shell is further sleeved outside the gun barrel to build a water cooling channel.

[0028] The coaxial stabilizer 1 has multiple through holes inside, which are respectively sealedly connected with the bore 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 coaxial stabilizer 1 mainly functions to ensure stable, safe and efficient combustion in the combustion chamber.

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

[0030] Further, the coaxial stabilizer 1 is fixedly sealed with 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 shell 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 with one end of the connector 4, and is sealed by using a high-temperature-resistant O-ring. Further, the combustion chamber 2 integrates a full combustion space and a Laval nozzle structure, that is Figure 1 The middle part is composed of a large space section (i.e. a constant diameter section), a converging section, a throat, and an expanding section, wherein the constant diameter section is the full combustion space, and the converging section, the throat, and the expanding section constitute the Laval nozzle structure. The combustion chamber 2 can make the jet velocity of the flame jet from the outlet thereof exceed the sound velocity.

[0032] Further, because the temperature (up to about 3300℃) and the pressure (9-11 Bar) of the combustion system of the spray gun of the present application are higher than those of a common supersonic spray gun, the material of the combustion chamber 2 must be a material with high melting point and high thermal conductivity. In the present embodiment, pure copper material is used, and the pure copper material is subjected to related treatment such as grain refinement to improve the tensile strength.

[0033] The spray gun shell 3 is sealingly connected with the connector 4, and is then fastened by the second fastening sleeve 17.

[0034] The connector 4 is an axisymmetric structure. The axial through hole at the center of the axis is a flame passage. There are multiple axisymmetric axial through holes near the outer side, which are water cooling passages. There are two axisymmetric radial through holes, which are carrier gas and hydrogen passages, and are used for inserting the powder feeding needle.

[0035] Further, one end of the connector 4 is connected with the outlet of the combustion chamber 2, and is sealed by using a high-temperature-resistant O-ring. The other end of the connector 4 is connected with the gun barrel 8, and is sealed by using a high-temperature-resistant O-ring. The inside of the combustion chamber, the axial through hole at the center of the axis of the connector, and the inside of the gun barrel together constitute the flame passage. The main functions of the connector 4 are: 1. serving as a transition system between the combustion chamber 2 and the gun barrel 8, sharing the combustion task of the combustion chamber 2, and being the starting point of the super-combustion (supersonic combustion), which can further increase the difference between the bore pressure and the atmospheric pressure, further increase the temperature of the flame, and further increase the jet velocity; and 2. serving as a clamp for fixing the input carrier gas and hydrogen device. Further, the material of the connector 4 must also have the same performance as the combustion chamber 2.

[0036] The powder feeding needle 6 is sealingly installed in the radial through hole of the connector 4, and one end thereof is connected with the flame at the center of the axis of the connector 4. The material of the section of the powder feeding needle 6 that extends into the flame must have super-high wear resistance and melting point, such as tungsten steel. The other end of the powder feeding needle 6 is sealingly and fasteningly connected with the outlet of the three-way adapter 5. One end of the three-way adapter 5 is sealingly connected with the carrier gas pipe, which is the carrier gas inlet. The sprayed powder is carried by the carrier gas and is input. In the present embodiment, nitrogen is used as the carrier gas, and the pressure is 1.2-1.6 MPa. The second end of the three-way adapter 5 is connected with the hydrogen pipe, which is the hydrogen inlet, and the pressure is 1.2-1.6 MPa. The third end of the three-way adapter 5 is connected with the powder feeding needle 6, which is the outlet of the mixed gas of nitrogen and hydrogen.

[0037] The ends of the barrel housing 7 are sealed to the coupler 4 and barrel 8, respectively, using high-temperature O-rings. The connection between the barrel housing and the coupler is secured by a third fastening sleeve 19. Furthermore, the space enclosed by the spray gun housing 3, the coaxial stabilizer 1, the combustion chamber 2, the coupler 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. Cooling water in the spray gun's water-cooling channel flows in the following order: 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 coupler 4, the space enclosed by the barrel 8 and the barrel housing 7, the return pipe 18, and finally the water-cooling outlet channel 16.

[0038] In this embodiment, the barrel 8 is an axisymmetric hollow structure, the rear end of which is sealed with the connector 4. The through hole in the axial direction of the barrel 8 is diffused along the direction of the flame spray, and the diameter of the through hole becomes larger and larger, and remains unchanged when the diameter reaches the designed value. Figure 1 As shown, the two sections of barrel 8, from left to right, utilize two different diffusion angles. The left section has a larger diffusion angle, which rapidly releases the flame's internal energy into kinetic energy, preventing excessively concentrated and high pressure and temperature in the scramblase phase. The right section has a smaller diffusion angle, which more gradually releases the flame's internal energy and continuously increases its velocity. Compared to existing supersonic spray gun barrels, the diffuser structure of barrel 8 more rapidly releases and converts a higher level of flame's internal energy into kinetic energy, further increasing flame velocity.

[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. Its main function is to monitor the pressure inside the 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 on the market can be used.

[0041] The fuel needle 11 is sealed and installed in the through hole at the axis of the coaxial stabilizer 1, and its outlet is also in the through hole at the axis 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. It is a conventional combustion oxygen supply pipe, and 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 delivering oxygen throughout the entire ignition and spraying process, and the flow rates of oxygen and aviation kerosene maintain a constant fuel-oxygen ratio to ensure sufficient combustion of the fuel.

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

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

[0046] In the above scheme, the fastening sleeve is used to press the contact between the coaxial stabilizer, the combustion chamber, the spray gun shell, the coupling or the gun barrel shell by screwing, so as to prevent them from being moved by the pressure in the gun.

[0047] According to a specific embodiment of the present application, the working method of the super-combustion hypersonic flame spray gun device comprises the following steps:

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

[0049] 2. Execute the ignition program, and ignite the ignition needle 10 by power supply. The aviation kerosene supply and the oxygen supply of the No. 1 oxygen input pipe 12 are simultaneously increased according to a certain fuel-oxygen ratio, so that the flame flow speed of the spray gun reaches the conventional 8 Mach.

[0050] 3. Start the oxygen supply of the No. 2 oxygen input pipe 13, and start the hydrogen supply, so that the hydrogen and the carrier gas are mixed together and enter the flame space of the coupling 4. The flame speed of this section exceeds the sound speed, and belongs to supersonic flame flow. The hydrogen and the oxygen have a super-high-efficiency combustion in the supersonic flame flow, further increase the bore pressure and the flame temperature, and increase the pressure difference between the bore pressure and the atmospheric pressure from the conventional 6-8 Bar to 9-11 Bar, and increase the flame temperature from the conventional 3000℃ to about 3300℃, so as to further increase the speed of the spray gun jet flame, and increase the flame speed to more than 10 Mach.

[0051] 4. After the flame is stabilized, start the powder feeding, and perform the spraying operation.

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

Claims

1. A scramjet hypersonic flame spray gun device, characterized in that: include: A coaxial stabilizer, a combustion chamber, a coupler, 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 inlet pipe, and a No. 2 oxygen inlet pipe. 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, 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 outside the combustion chamber, and a gun barrel housing is provided outside the gun barrel. Both ends of the spray gun housing are sealed and fixed to the coaxial stabilizer and the coupling. 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 coupler for feeding a carrier gas carrying spray powder and hydrogen into the flame channel of the central through hole.

2. The scramjic hypersonic flame spray gun device according to claim 1, characterized in that: The coaxial stabilizer has multiple through holes inside, which are respectively sealed with the gun barrel pressure measuring tube, ignition needle, fuel needle, oxygen input pipe No. 1, and oxygen input pipe No.

2. Among them, the two through holes for installing the fuel needle and oxygen input pipe No. 1 intersect and converge inside the coaxial stabilizer and merge into one through hole at one end close to the combustion chamber.

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

4. The scramjic hypersonic flame spray gun device according to claim 1, characterized in that: A three-way adapter is also provided on the connector, one end of which is sealed and connected to the carrier gas tube, which is the carrier gas inlet, one end is connected to the hydrogen tube, which is the hydrogen inlet, and one end is connected to the powder feeding needle, which is the outlet of the carrier gas and hydrogen mixture. The carrier gas contains spray powder.

5. The scramjic hypersonic flame spray gun device according to 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 scramjic hypersonic flame spray gun device according to claim 1, characterized in that: The through hole on the axis of the barrel is along the direction of flame spraying and is in a shape of maintaining diameter after diffusion. The diffusion part includes two diffusion sections with different diffusion angles. The diffusion angle of the barrel section close to the connector is larger, and the diffusion angle of the barrel section close to the muzzle is smaller.

7. The scramjic hypersonic flame spray gun device according to 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 operating 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 to the No. 1 oxygen input pipe to set the gun parameters; 2) Execute the ignition program, ignite the ignition needle, and increase the fuel supply and the oxygen supply of the No. 1 oxygen input pipe according to the set fuel-oxygen ratio at the same time, so that the flame velocity of the spray gun reaches Mach 8; 3) Open the oxygen supply of oxygen input pipe No. 2 and the hydrogen supply, so that the hydrogen and carrier gas converge and mix together and enter the flame channel of the connector. The flame speed in this section exceeds the speed of sound, belonging to supersonic flame flow. Hydrogen and oxygen burn with ultra-high efficiency in the supersonic flame flow, further increasing the gun barrel pressure and flame temperature, thereby further increasing the speed of the spray gun flame flow, making the flame flow speed increase 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 feeding, then stop the hydrogen supply and stop the oxygen supply of No. 2 oxygen input pipe, then stop the fuel supply and the oxygen supply of No. 1 oxygen input pipe. After the flame is extinguished, open the oxygen supply of 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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