Repair device for air engine flame tube venturi and construction method

Abstract

The application discloses a kind of repair device and construction method for aero-engine combustion chamber flame tube venturi, belong to aero-engine maintenance process equipment design manufacturing technical field.It provides a kind of repair device and construction method with relatively high repair success rate, which can significantly reduce the replacement rate.The repair device includes a welding assembly, and the repair device further includes a cooling support protection assembly.During the welding repair process of the flame tube venturi, the welded part of the flame tube venturi, the nearby area connected to the welded part, and the surrounding airspace are in the protective environment formed by the cooling support protection assembly and the sleeve of the aero-engine combustion chamber.The flame tube venturi is effectively protected by the cooling support protection assembly during the welding process, which can reduce or even avoid the oxidation of the venturi during the welding process, and improve the repair success rate, thereby significantly reducing the replacement rate.

Description

Technical Field

[0001] The present invention relates to a repair device, and more particularly to a repair device for a venturi tube in an aircraft engine combustion chamber, belonging to the technical field of aircraft engine repair and maintenance process equipment design and manufacturing. The present invention also relates to a construction method for repairing a venturi tube in an aircraft engine combustion chamber using the repair device. Background Art

[0002] The main combustion chamber of an aircraft turbofan engine injects fuel into the main airflow after the compressor, ensuring stable combustion of the fuel-air mixture under various conditions and generating a temperature field that meets turbine inlet requirements. Each head of the flame liner includes intake devices such as the primary vortex finder, venturi, radial vortex finder, sleeve, and baffle. During operation, the flame liner is subject to high ambient temperatures, complex loads, and harsh operating conditions, which can easily lead to various failures such as cracks, carbon deposits, and deformation in the flame liner and its accessories. Currently, there are relatively mature repair processes and methods for some high-failure components, such as cracks in the flame liner outer wall, weld separation of the flame liner head combustion hole guide sleeve, and wear of the flame liner baffle. For example, patent application number 201911129466.0 describes a flame liner vacuum electron beam welding deformation control method and device. However, further improvements are needed for the repair of some components with medium and low failure rates to shorten engine assembly time. Burns or cracks in the venturi bell of the flame tube are considered low-to-medium failures. These burns or cracks are located in the thin wall near the sleeve and radial vortex finder, resulting in a failure rate of approximately 1 / 5, or 3-4 failures per engine. Currently, there are no patents or literature reporting on rapid and convenient repair technologies.

[0003] Existing repair methods include replacement and TIG welding. The TIG welding repair process involves first removing the main vortex flow generator, then cutting at the ablation / crack location to expose the high-temperature alloy structure of the venturi tube matrix, and finally repairing the surface gap with TIG welding. Due to the confined location of the venturi tube, the current repair process has the following problems:

[0004] 1. The back of the venturi tube has a sleeve, radial vortex generator and splash plate, and the space is narrow. Therefore, during welding, the space on the back of the venturi tube cannot be filled with argon gas, which makes it impossible to better protect the back of the weld. This eventually leads to serious oxidation at the welds on the back of some venturi tubes. If the oxidation is too severe, new parts can only be replaced. The replacement of new parts involves cutting the venturi tube, sleeve and splash plate as a whole, grinding burrs, and finally welding the new parts. Since the venturi tube is not round, spot welding and positioning are required before welding, and full welding is performed after positioning is completed. Therefore, this process is very time-consuming. A single replacement part takes at least 2-3 hours. Each engine takes a lot of time to repair the flame tube and venturi, which seriously affects the engine assembly time.

[0005] 2. If the burn / crack of the Venturi tube is large, the incision will also be larger. During the welding process, if the welding current, temperature and time are not properly controlled, it is very easy for the molten welding wire liquid to flow into the inside of the Venturi tube incision, and then form a large weld bead on the back of the Venturi tube. The gap on the back of the Venturi tube is small, and there is an external air intake hood next to it. The existing grinding tooling cannot extend to the position of the weld bead to grind it. Since the existing high-power grinding endoscopes are all straight tubes, they cannot penetrate into the back of the curved Venturi tube. Although there are hose grinding endoscopes in medicine that can be extended to the back of the Venturi tube, due to their low power, they cannot grind hard high-temperature alloys. If the weld bead is not removed, it will affect the airflow channel, so it can only be replaced with a new part.

[0006] 3. The faulty part of the venturi is usually thin-walled, with a thickness between 0.85-1.25mm. Therefore, welding repairs require very high welder skills. Excessive current, high temperature, or prolonged welding can rapidly increase the local temperature of the venturi, causing it to soften at high temperatures. This can easily lead to further crack expansion and ultimately failure. The complex replacement process significantly increases engine maintenance cycles and severely impacts engine integrity.

[0007] 4. Venturi tube cracks can be repaired using vacuum welding equipment equipped with a robotic arm. While this repair is effective, due to the rarity of Venturi tube failures and the fluid location of cracks, assembly line repair is not feasible, as the clamping position varies with each installation, resulting in low repair efficiency. Furthermore, the equipment investment is high. The large flame tube (over 1 meter in diameter) requires large vacuum welding equipment. Domestic vacuum brazing furnaces cost over 3 million yuan each, with imported equipment costing even more. The robotic arm costs approximately 1 million yuan domestically, with imported equipment costing even more. This does not include equipment maintenance costs. Furthermore, given the large number of aircraft engine models currently operating in my country, repair shops must frequently adjust the process layout of their engine repair lines to accommodate the diverse number of turbofan engines being repaired. Using large-scale automated equipment to repair Venturi tube failures would not only be costly but would also severely impact the overall process layout of the repair line.

[0008] Therefore, the current maintenance method is: if the crack is small, welding repair is performed; if the crack is large, the part is directly replaced. Although the repair process is complicated, it increases the engine maintenance cycle and affects the completeness of the engine, the production equipment cost investment is minimal and the process layout can be adjusted flexibly. Therefore, based on the equipment solution, it is necessary to design a portable repair device and method for the venturi tube of the combustion chamber of a certain type of aviation turbofan engine. Not only does it have good adaptability in process layout adjustment, it can also reduce the difficulty of repairing the venturi tube of the venturi tube and improve the repair qualification rate. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a repair device for the venturi tube of the flame tube of the combustion chamber of an aircraft engine, which has a relatively high repair success rate and can significantly reduce the replacement rate, and a construction method for repairing the venturi tube of the flame tube of the combustion chamber of an aircraft engine using the repair device.

[0010] The technical solution adopted to solve the above technical problems is: a repair device for the venturi tube of the flame tube of an aircraft engine combustion chamber, including a welding assembly, and the repair device also includes a cooling support and protection assembly; during the welding repair process of the flame tube venturi tube, the welded part of the flame tube venturi tube, the nearby area connected to the welded part, and the surrounding airspace are in a protective environment constructed by the cooling support and protection assembly and the sleeve of the aircraft engine combustion chamber.

[0011] Furthermore, the cooling support protection assembly includes at least a fixing assembly, a sealing assembly and a protective environment construction system. The protective environment construction system is detachably fixed to the flame tube venturi that needs to be repaired through the fixing assembly, and the gap between the sleeve and the protective environment construction system is sealed by the sealing assembly.

[0012] A preferred embodiment of the above scheme is that the protective environment construction system includes a protective environment construction frame and an argon gas conveying component group, a main argon gas conveying channel is provided on the protective environment construction frame, the gas output end of the argon gas conveying component group is connected to the main argon gas conveying channel, the protective environment construction frame is detachably fixed on the flame tube venturi that needs to be repaired through the fixing component, and the sealing component is padded in the gap between the sleeve and the protective environment construction frame.

[0013] Furthermore, the sealing assembly is composed of a fluororubber sealing ring, and an annular groove is provided at a corresponding position at one end of the protective environment frame. The aircraft engine combustion chamber also includes a splash plate, and the side of the fluororubber sealing ring filled in the annular groove that is exposed from the annular groove is connected to the end face of the sleeve and the splash plate of the aircraft engine combustion chamber.

[0014] The preferred embodiment of the above scheme is that the fixing assembly includes a pressure plate and connecting bolts, the protective environment construction frame is a T-shaped structure, the main argon gas delivery channel is arranged on the vertical edge of the T-shaped protective environment construction frame, the environmental construction step is composed of the horizontal edge of the T-shaped protective environment construction frame, the flange is arranged on the horizontal edge of the environmental construction step, the annular groove is arranged on the flange of the environmental construction step, the column is arranged at the center position of the environmental construction step, an argon gas uniformly distributed outlet channel perpendicular to the main argon gas delivery channel is arranged inside the column, and an outlet groove extending circumferentially and connected to the argon gas uniformly distributed outlet channel is arranged at the root of the column, the outlet groove, the flange, the side of the column and the sleeve and radial vortex finder of the aircraft engine combustion chamber constitute the peripheral airspace; a threaded hole is arranged on the outer end surface of the column, and the protective environment construction frame can be detachably fixed to the flame tube venturi that needs to be repaired through the pressure plate in cooperation with the connecting bolt and the threaded hole.

[0015] Furthermore, an argon plug is provided on the outer end face of the cylinder, and a contoured arc surface extending in the circumferential direction is also provided on the outer end face of the argon plug; an annular air duct is also provided on the back side of the contoured arc surface, and a threaded hole is provided on the argon plug, and the cracks in the venturi tube that need to be repaired on the back arc surface of the flame tube venturi tube are inserted into the contoured arc surface of the protective environment construction frame that is fixed in place.

[0016] The preferred embodiment of the above scheme is that the protective environment construction frame and the heat dissipation copper tube are made of red copper or a copper alloy with a copper content of more than 90%, wherein the inner diameter of the main argon gas delivery channel is 6-8mm and the wall thickness is 3-5mm, the inner diameter of the argon gas uniform distribution outlet channel in the middle part is 3-4mm and the wall thickness is 3-5mm, the number of argon gas uniform distribution outlet channels is 5-8 and is evenly distributed, and the thickness of the flange plate at the connection with the engine flame tube sleeve and the splash plate is not less than 8mm.

[0017] Furthermore, a fitting clearance of 0.3-0.5 mm is left between the arc surface on the back of the flame tube venturi and the contoured arc surface, a fitting clearance of 0.4-0.7 mm is left between the inner hole of the venturi and the argon plug, and the gap of the former must be smaller than the gap of the latter, and a fitting clearance of 1.5-2 mm is left between the annular air duct and the sleeve. The welding assembly is an argon arc welding machine.

[0018] The preferred embodiment of the above scheme is that the cooling support protection component also includes a circulating heat dissipation cooling system, and the heat dissipation copper tube of the circulating heat dissipation cooling system is wrapped around the vertical edge of the T-shaped protective environment frame. The number of turns of the heat dissipation copper tube is 8-15 turns, and it is fixed to the protective environment frame by copper welding. The water inlet and outlet of the heat dissipation copper tube are also respectively installed with quick connectors through threaded connection structures, and the water pipes of the circulating heat dissipation water cooling system are quickly connected to the heat dissipation copper tube through the threaded connection structure.

[0019] A construction method for repairing a venturi tube of a combustion chamber of an aircraft engine using the repair device, the construction method comprising the following steps:

[0020] 1) Install the fluororubber sealing assembly in the annular groove of the protective environment frame, and fix it to the threaded holes on the protective environment frame through the connecting bolts and the pressure plate, so that the venturi tube and the T-shaped protective environment frame are fixed together, and the fluororubber sealing ring can fit tightly with the sleeve and the splash plate to form a closed cavity on the back of the venturi tube;

[0021] 2) During the process of forming the closed cavity in step 1), the gap between the T-shaped protective environment frame and the curved surface of the back of the Venturi tube is finely adjusted, and the contoured curved surface of the T-shaped protective environment frame is made to fit the Venturi crack as closely as possible;

[0022] 3) Quickly connect and assemble the argon gas delivery component assembly through the quick connector;

[0023] 4) Quickly connect and assemble the circulating heat dissipation water cooling system through quick connectors;

[0024] 5) Open the external argon gas cylinder to create an argon gas protective environment;

[0025] 6) Turn on the welding machine of the welding system and set the welding current to prepare for welding;

[0026] 7) Inflate with argon for at least 15 seconds to exhaust the air in the back cavity of the venturi tube, so that the gap between the back cavity of the venturi tube and the protective environment structure is completely filled with argon gas, thereby building the protective environment structure system. Switch the welder to argon arc welding mode and use argon arc welding to perform cladding on the front surface of the venturi tube;

[0027] 8) After welding is completed, pause for about 30 seconds. During this period, continue to supply argon gas and circulating water so that the venturi tube is protected by argon gas during the cooling process and is not oxidized. In addition, it will not cause burns during disassembly.

[0028] 9) Finally, remove the protective environment frame and use a pneumatic grinder to grind the welded area on the venturi tube surface until it is smooth, completing the repair work;

[0029] The process from assembly to welding and removing the protective environment frame takes no more than 5 minutes, thus greatly saving the time required for engine assembly.

[0030] The welding parameters are as follows: HGH605 welding wire, 2.0-2.5mm diameter, welding time approximately 1-1.5mm; argon gas flow rate of 15-18L / min and pressure of 3-6kPa for an argon protective environment; circulating cooling water temperature not exceeding 28°C and pressure of 0.25-1.0MPa; if cooling water is unavailable, low-pressure compressed air can be used for heat dissipation, with a temperature not exceeding 25°C and a pressure of 0.4-1.0MPa.

[0031] The beneficial effects of the present invention are as follows: the technical solution provided by the present application is based on the existing welding assembly, and by providing a repair device including a cooling support and protection assembly; and during the welding repair process of the flame tube venturi tube, the welded portion of the flame tube venturi tube, the nearby area connected to the welded component, and the surrounding airspace are placed in a protective environment constructed by the cooling support and protection assembly and the sleeve of the aircraft engine combustion chamber. In this way, since the flame tube venturi tube is effectively protected by the cooling support and protection assembly during the welding process, the oxidation of the venturi tube during the welding process and the occurrence of defects such as weld nodules can be effectively reduced or even avoided. This achieves the purpose of improving the repair success rate, significantly reducing the replacement rate, and greatly shortening the repair time, while achieving one-time repair success as much as possible, reducing the replacement rate to the lowest possible level, or even to zero. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of the repair device for the flame duct venturi of an aircraft engine combustion chamber of the present invention, involving the flame duct venturi, sleeve, splash plate and other related components in the assembly position;

[0033] Figure 2 The present invention is a structural schematic diagram of a repair device for a venturi tube in a combustion chamber of an aircraft engine in use.

[0034] Figure 3 The invention provides a repair device for a flame duct venturi of an aircraft engine combustion chamber, and relates to a structural schematic diagram of the flame duct venturi in a state to be repaired.

[0035] Figure 4 The present invention is a schematic diagram of the three-dimensional structure of the repair device for the venturi of the flame tube of the combustion chamber of an aircraft engine.

[0036] The following are marked in the figure: welding assembly 1, welding wire 1-1, venturi tube 2, venturi tube back arc surface 2-1, venturi tube crack 2-2, venturi tube inner hole 2-3, fixing assembly 3, pressure plate 3-1, connecting bolt 3-2, sealing assembly 4, cooling support protection assembly 5, protective environment construction system 6, protective environment construction frame 7, main argon gas delivery channel 7-1, environmental construction step 7-2, flange 7-2-1, annular groove 7-2-2, column 7-2-3, argon gas uniformity Outlet duct 7-3, outlet groove 7-4, argon plug 7-5, contoured arc surface 7-6, annular air duct 7-7, threaded hole 7-8, argon delivery component group 8, circulating heat dissipation water cooling system 9, heat dissipation copper tube 9-1, water pipe 9-2, quick connector 10, sleeve 11, splash plate 12, main vortex finder 13, main vortex finder pressure plate 14, radial vortex finder 15, inner air inlet hood 16, outer air inlet hood 17, flame tube inner wall 18, flame tube outer wall 19, inner support ring 20. DETAILED DESCRIPTION

[0037] like Figure 1 、 Figure 2 、 Figure 3 and Figure 4The present invention provides a repair device for a venturi tube in a flame duct of an aircraft engine combustion chamber, which has a relatively high repair success rate and can significantly reduce the replacement rate, and a construction method for repairing a venturi tube in a flame duct of an aircraft engine combustion chamber using the repair device. The repair device includes a welding assembly 1, and the repair device also includes a cooling support and protection assembly 5. During the welding repair process of the flame duct venturi tube 2, the welded portion of the venturi tube crack 2-2 of the flame duct venturi tube 2, the vicinity of the connection between the welded component and the surrounding airspace are placed in a protective environment constructed by the cooling support and protection assembly 5, the sleeve 11 of the aircraft engine combustion chamber, and the splash plate 12. The technical solution provided by the present application is based on the existing welding assembly 1, by providing a repair device including a cooling support and protection assembly 5. During the welding repair process of the flame duct venturi tube 2, the welded portion of the flame duct venturi tube, the vicinity of the connection between the welded component and the surrounding airspace are placed in a protective environment constructed by the cooling support and protection assembly 5, the sleeve 10 of the aircraft engine combustion chamber, and the splash plate. In this way, since the flame tube venturi is effectively protected by the cooling support protection component during the welding process, the oxidation of the venturi during the welding process, or the occurrence of weld nodules and softening and deformation of the venturi due to excessive cracks and long welding time can be effectively reduced or even avoided, thereby achieving the purpose of improving the repair success rate and repair speed and significantly reducing the replacement rate. At the same time, one-time repair success can be achieved as much as possible, and the replacement rate can be reduced to the lowest possible level, or even to 0.

[0038] In the above embodiment, in combination with existing technology, the welding assembly 1 is preferably an argon arc welder. Accordingly, to accommodate the confined space of the flame tube venturi 2 while simultaneously constructing a protective environment as effectively as possible, the cooling support and protection assembly 5 described in this application includes at least a fixing assembly 3, a sealing assembly 4, and a protective environment construction system 6. The protective environment construction system 6 is detachably fixed to the flame tube venturi 2 requiring repair via the fixing assembly 3, and the gap between the sleeve 11 and the protective environment construction system 6 is sealed by the sealing assembly 4. In this case, the protective environment construction system 6 preferably includes a protective environment construction frame 7 and an argon gas conveying assembly 8. A main argon gas conveying channel 7-1 is provided on the protective environment construction frame 7, and the gas output end of the argon gas conveying assembly 8 is connected to the input end of the main argon gas conveying channel 7-1. The protective environment construction frame 7 is removably fixed to the flame tube venturi 2 to be repaired via the fixing assembly 3. The sealing assembly 4 is cushioned in the gap between the sleeve 11 and the protective environment construction frame 7. Accordingly, the sealing assembly 4 is preferably composed of a high-temperature resistant fluororubber sealing ring. An annular groove 7-2-2 is provided at a corresponding position on one end of the protective environment construction frame 7. The aircraft engine combustion chamber also includes a splash plate 12. The side of the fluororubber sealing ring filled in the annular groove 7-2-2 that is exposed from the annular groove 7-2-2 abuts against the end surfaces of the sleeve 2 and splash plate 10 of the aircraft engine combustion chamber. The fixing assembly 3 preferably includes a pressure plate 3-1 and connecting bolts 3-2.At the same time, in order to adapt to the structure of the flame tube venturi 2 itself, improve the construction effect of the protective environment construction system 6, and facilitate the arrangement of cooling components, the present application sets the protective environment construction frame 7 to a T-shaped structure, the main argon gas delivery channel 7-1 is set on the vertical side of the T-shaped protective environment construction frame 7, the environmental construction step 7-2 is composed of the horizontal side of the T-shaped protective environment construction frame 7, the flange 7-2-1 is set on the horizontal side of the environmental construction step 7-2, the annular groove 7-2-2 is set on the flange 7-2-1 of the environmental construction step 7-2, the column 7-2-3 is set at the center position of the environmental construction step 7-2, and the environmental construction step 7-2 is provided at the center of the environmental construction step 7-2. An argon uniformly distributed outlet duct 7-3 perpendicular to the main argon delivery duct 7-1 is provided on the column 7-2-3 of 7-2, and an outlet groove 7-4 extending circumferentially and connected to the argon uniformly distributed outlet duct 7-3 is provided at the root of the column 7-2-3. The outlet groove 7-4, the flange 7-2-1, the side of the column 7-2-3 and the sleeve 11 and radial vortex finder 12 of the aircraft engine combustion chamber constitute the peripheral airspace; a threaded hole 7-8 is provided on the outer end face of the column 7-2-3, and the protective environment construction frame 7 is detachably fixed on the flame tube venturi 2 that needs to be repaired through the pressure plate 3-1 in cooperation with the connecting bolt 3-2 and the threaded hole 7-8. At the same time, an argon plug 7-5 is provided on the outer end face of the column 7-2-3, and a contoured arc surface 7-6 extending in the circumferential direction is also provided on the outer end face of the argon plug 7-5; an annular air duct 7-7 is also provided on the back of the contoured arc surface 7-6, and the threaded hole 7-8 is provided on the argon plug 7-5, and the venturi crack 2-2 that needs to be repaired on the back arc surface 2-1 of the flame tube venturi is inserted into the contoured arc surface 7-6 of the protective environment construction frame 7 that is fixed in place, and a clearance fit structure is formed between the end of the flame tube venturi 2 that needs to be repaired and the contoured arc surface 7-6.

[0039] The cooling support protection assembly described in the present application also includes a circulating heat dissipation water cooling system 9, and the heat dissipation copper tube 9-1 of the circulating heat dissipation water cooling system 9 is wound around the vertical edge of the T-shaped protective environment construction frame 7 and fixed by welding.

[0040] Thus, when the present application uses the repair device to repair the venturi of the flame tube of the aircraft engine combustion chamber, the following steps can be performed:

[0041] 1. Install the fluororubber sealing ring in the annular groove 7-2-2 of the T-shaped environmental protection frame 7. Secure it to the threaded hole 7-8 on the T-shaped environmental protection frame 7 using the connecting bolts 3-2 and the pressure plate 3-1. This secures the venturi tube 2 to the T-shaped environmental protection frame 7. Ensure that the fluororubber sealing ring fits tightly against the sleeve 11 and the splash plate 12, forming a closed cavity at the back of the venturi tube 2.

[0042] 2) During the process of forming the closed cavity in step 1), the gap between the T-shaped protective environment construction frame 7 and the curved surface 2-1 on the back of the Venturi tube is finely adjusted, and the contoured curved surface 7-6 of the T-shaped protective environment construction frame 7 is made to fit the Venturi crack 2-2 as closely as possible;

[0043] 3) Quickly connect and assemble the argon gas delivery component assembly 8 through the quick connector 10;

[0044] 4) Quickly connect and assemble the circulating heat dissipation water cooling system 9 through the quick connector 10;

[0045] 5) Open the external argon gas cylinder to create an argon gas protective environment;

[0046] 6) Turn on the welding machine of the welding system and set the welding current to prepare for welding;

[0047] 7) Inflate with argon for at least 15 seconds to evacuate the air in the back cavity of the venturi tube, so that the gap between the back cavity of the venturi tube 2 and the protective environment construction frame 7 is completely filled with argon gas, thereby constructing the protective environment construction system 6. Switch the welding machine to argon arc welding mode and use argon arc welding to perform surfacing welding on the positive surface of the venturi tube crack 2-2;

[0048] 8) After welding is completed, pause for about 30 seconds. During this period, continue to supply argon gas and circulating water so that the venturi tube will continue to be protected by argon gas during the cooling process and will not be oxidized. In addition, it will not be burned during disassembly.

[0049] 9) Finally, remove the protective environment frame 7 and use a pneumatic grinder to grind the welded portion of the venturi tube 2 until the surface is smooth, completing the repair work.

[0050] The process from assembly to welding and removing the protective environment frame takes no more than 5 minutes, thus greatly saving the engine assembly time.

[0051] The welding parameters are as follows: HGH605 wire, 2.0-2.5mm diameter, and a welding time of approximately 1-1.5mm. When creating an argon protective environment, the argon flow rate is 15-18L / min, and the supply pressure is 3-6kPa. The circulating cooling water temperature should not exceed 28°C, and the pressure should be 0.25-1.0MPa. If cooling water is unavailable, low-pressure compressed air can be used for heat dissipation. The temperature of the low-pressure compressed air should not exceed 25°C, and the pressure should be 0.4-1.0MPa.

[0052] There is a fitting clearance of 0.3-0.5mm between the arc surface 2-1 on the back of the flame tube venturi and the contoured arc surface 7-6, and a fitting clearance of 0.4-0.6mm between the inner hole 2-3 of the venturi and the argon plug 7-5, and the clearance of the former must be smaller than the clearance of the latter. There is a fitting clearance of 1.5-2mm between the annular air duct 7-7 and the sleeve 11 to facilitate the adjustment of the protective environment structure frame 7 so that the contoured arc surface 7-4 fits the venturi crack 2-2 as closely as possible.

[0053] The T-shaped protective environment construction frame 7 and the heat dissipation copper pipe 9-1 need to be made of brass pipes or copper alloys with a copper content exceeding 90% to ensure good thermal conductivity.

[0054] In summary, the technical solution provided by this application also has the following characteristics:

[0055] 1) A sealed cavity filled with argon is formed on the back of the venturi tube by the tooling, so that the argon gas can enter the argon uniform distribution outlet 7-3 through the main argon gas delivery channel 7-1, then exit the annular groove 7-4 and finally enter the cavity formed by the venturi back arc surface 2-1 and the contoured arc surface 7-6 through the annular gas channel 7-7, thereby constructing an argon protective environment, so that it can effectively protect the welding layer from oxidation;

[0056] 2) Because the gap between the welding fixture (i.e., the aforementioned protective environment frame 7) extending deep into the back of the Venturi tube and the curved surface 2-1 on the back of the Venturi tube is small (the position of the welding fixture can be fine-tuned to align the fixture with the Venturi tube crack 2-2), the welding fixture material has poor weldability with high-temperature alloys (high temperatures are required to weld brass and high-temperature alloys together), and the welding fixture temperature is low, the molten welding wire flows into the Venturi tube crack and contacts the low-temperature welding fixture, causing it to solidify rapidly. The distance between the welding fixture and the Venturi tube crack is small, even zero, and the micro-pressure inside the cavity effectively prevents the molten welding wire from flowing, thus avoiding the formation of weld nodules. During the welding process, due to the excellent thermal conductivity of brass at the junction of the Venturi tube and the brass welding fixture, and the circulating water dissipates heat, the softening phenomenon caused by prolonged welding is avoided.

[0057] The technical solution of this application is further described below through specific embodiments:

[0058] In order to solve the above-mentioned faults, a combustion chamber flame tube venturi repair device and method are provided to solve the problems of severe oxidation at the welding point due to the narrow space at the back of the venturi tube, which makes it impossible to provide argon protection, or weld nodules due to large cracks, and the problem of the venturi tube softening and deforming due to excessive temperature caused by long-term welding.

[0059] To achieve the above objectives, this application adopts the following technical solutions:

[0060] The present application discloses a device for repairing a venturi tube in an engine combustion chamber flame tube, comprising: a welding fixture, fastening bolts, a pressure plate, a fluororubber seal, a circulating cooling water pump, a cooling copper tube, an argon gas cylinder, an argon gas flowmeter, an argon gas pressure gauge, a welding machine, welding wire, a compressed air PU tube, and a quick connector. The welding fixture herein is a protective environment frame. The fluororubber seal is mounted on a groove on the end face of the welding fixture. The pressure plate connects the welding fixture to the venturi tube via fastening bolts. A quick connector is threadedly mounted on the bottom of the welding fixture. The argon gas cylinder is quickly connected to the welding fixture via a quick connector and a compressed air PU tube. The argon gas flowmeter and argon gas pressure gauge are quickly connected between the welding fixture and the argon gas cylinder via a compressed air PU tube. The cooling copper tube is wrapped around the welding fixture and fixed to and in contact with the welding fixture by brazing. The inlet and outlet of the cooling copper tube are threadedly mounted with quick connectors. The circulating cooling water pump is quickly connected to the cooling copper tube via the compressed air PU tube and the quick connector.

[0061] Preferably, the welding tool is made of red copper or a copper alloy with a copper content of more than 90%, the inner diameter of the main argon delivery channel is about 6-8 mm, and the wall thickness is 3-5 mm. The inner diameter of the argon uniform outlet channel in the middle part is about 3-4 mm, and the wall thickness is 3-4 mm. The number of argon uniform outlet channels can be 5-8 and evenly distributed on the welding tool; the thickness of the flange at the junction with the engine flame tube sleeve and the splash plate is not less than 8 mm and should not exceed 14 mm. Otherwise, it is too thick and the welding tool is too heavy to be operated with one hand; or The flange is too thin, or the flange softens due to heat accumulation due to excessive heat conduction and slow heat conduction; the gap between the contoured arc surface of the welding fixture that penetrates into the back of the venturi tube and the back of the venturi tube is between 0.3-0.5mm; the gap between the argon gas plug in the center of the welding fixture and the inner hole of the venturi tube is between 0.4-0.7mm, and the former gap must be smaller than the latter. A gap of 1.5-2mm is left between the annular air duct of the welding fixture and the sleeve to facilitate the adjustment of the welding fixture position so that the contoured arc surface of the welding fixture fits the crack of the venturi tube as closely as possible.

[0062] Preferably, the fluororubber sealing ring is installed on the end face of the welding fixture by overfitting, and its thickness is 3-4mm; the fluororubber installation height can be level with the end face of the welding fixture or slightly higher, and its height does not exceed 1mm.

[0063] Preferably, the heat dissipating copper tube is also made of brass tube or copper alloy with a copper content of more than 90%. The inner diameter of the copper tube is about 4-6 mm and the wall thickness is 1-2 mm. The number of turns of the heat dissipating copper tube wrapped around the welding tool is not less than 8 turns, and should not exceed 16 turns, otherwise the welding tool will be too long and difficult to operate with one hand, and the heat dissipating copper tube is connected to the welding tool by welding to facilitate heat dissipation of the copper tube.

[0064] Preferably, the water inlet / outlet of the heat dissipation copper pipe is connected to the quick connector by a threaded connection. The circulating water pump can be quickly connected to the heat dissipation copper pipe through the compressed air PU pipe and the quick connector and provide cooling water to it, which facilitates the rapid disassembly and installation of the pipeline and water pump.

[0065] Preferably, the water supply pressure of the circulating water cooling water pump is not less than 0.25 MPa but not more than 1 MPa, and the circulating water supply temperature is not higher than 28°C, so that the temperature of the welding tooling during the welding process does not exceed 300°C.

[0066] Preferably, the inner diameter of the compressed air PU tube used to supply argon needs to be at least 1.1 times the inner diameter of the main argon inlet pipe of the welding tool to ensure the argon supply.

[0067] Preferably, the measuring range of the argon flow meter is 0-25 L / min, and the measuring range of the argon pressure gauge is a high-precision pressure gauge with a measuring range of 0-15 kPa.

[0068] A device and method for repairing a venturi tube of a combustion chamber of a certain type of aviation turbofan engine comprises the following steps:

[0069] S1: Install the fluororubber sealing ring on the end face of the welding fixture, and fix the venturi tube to the welding fixture by tightening the bolts and the pressure plate so that the fluororubber sealing ring can fit tightly with the sleeve and the splash plate.

[0070] S2: In the process of forming a relatively closed cavity, since there is a certain gap between the contoured arc surface of the welding tool and the arc surface of the back of the venturi tube, in order to prevent the metal liquid generated by the melting of the welding wire from flowing into the back of the venturi tube along the crack of the venturi tube, the position of the welding tool can be fine-tuned so that the contoured arc surface of the welding tool fits the crack of the venturi tube as closely as possible.

[0071] S3: Use the compressed air PU tube and quick connector to quickly connect the argon cylinder, flow meter, pressure gauge, and welding tooling.

[0072] S4: Quickly connect the circulating water pump and the heat dissipation copper pipe through the compressed air PU pipe and quick connector, and turn on the circulating water pump.

[0073] S5: Open the argon bottle, set the nitrogen flow rate to 10-15L / min, and the gas supply pressure to 4-8KPa, so that a slight pressure is generated inside the cavity.

[0074] S6: The argon filling time is about 15 seconds, so that the air in the back cavity of the venturi tube flows out from the cracks of the venturi tube and the gap between the inner hole of the venturi tube and the welding tooling, and the cavity on the back of the venturi tube is filled with argon gas, which plays a protective role during the welding process.

[0075] S7: After about 20 seconds, turn on the welding machine and set the current to 60±5A.

[0076] S8: After the cavity on the back of the venturi tube is filled with argon gas, the welding machine is switched to argon arc welding mode, and argon arc welding is used to perform surfacing welding on the surface of the venturi tube. The specification of the welding wire is HGH605, the diameter of the welding wire is 2.0-2.5mm, and the welding time is about 30-60s.

[0077] S9: After welding is completed, pause for about 30 seconds. During this period, continue to supply argon gas and circulating water so that the venturi tube is still protected by argon gas during the cooling process and is not oxidized. At the same time, the circulating water removes the heat generated by welding from the venturi tube and welding tooling to prevent burns during disassembly.

[0078] S10: After welding is completed, remove the welding tool and use a grinder to grind the welding part of the venturi tube surface to make it smooth.

[0079] Example 1

[0080] To further illustrate the present application and the technical means and effects employed to achieve the intended beneficial objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, provides a detailed description of the specific implementation methods, structures, features, and effects of the present application. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable form:

[0081] See also Figure 2This is a diagram of the venturi structure of a certain type of turbofan engine combustion chamber. The specific structure includes the venturi 2, sleeve 11, splash plate 12, main vortex finder 13, main vortex finder pressure plate 14, radial vortex finder 15, inner air intake hood 16, outer air intake hood 17, duct inner wall 18, duct outer wall 19, and inner support ring 20. The venturi is equipped with a main vortex finder 13, which is connected to the venturi 2 via the main vortex finder pressure plate 14. During maintenance, the main vortex finder pressure plate 14 must be removed with a grinder or angle grinder, and then the main vortex finder 15 must be removed to fully expose the upper surface of the venturi 2. There is a radial vortex finder 16 next to the venturi tube 2, and a sleeve 11 and a splash plate 12 below, which are connected together by welding; the inner air intake hood 16 and the outer air intake hood 17 are connected to the radial vortex finder 15 by welding, and the flame tube inner wall 118, the flame tube outer wall 19 and the inner support ring 20 are connected to the inner air intake hood 16 and the outer air intake hood 17 by welding, so that the flame tube forms a whole. During maintenance, usually only the main vortex finder and the main vortex finder pressure plate are removed. This results in a small gap position space for the venturi tube and great difficulty in maintenance. The main content of this application is to design a repair device and method for the venturi tube, so in the subsequent maintenance process, the part of disassembling the main vortex finder 13 and the main vortex finder pressure plate 14 will not be included.

[0082] See also Figure 1 As shown, the fluororubber sealing ring is installed in the annular groove of the welding fixture through an overfitting method. The pressure plate connects the welding fixture and the venturi tube by tightening bolts. Through the pressure plate and welding fixture, the fluororubber sealing ring is tightly fitted with the sleeve and splash plate of the flame tube, forming a small sealed cavity between the back of the venturi tube and the welding fixture. At the same time, the position of the welding fixture is adjusted so that the contoured arc surface on the welding fixture is as close as possible to the cracks in the venturi tube. The argon cylinder is quickly connected to the welding fixture via a compressed air PU tube and a quick connector. The argon flowmeter and argon pressure gauge are connected between the welding fixture and the argon cylinder via a compressed air PU tube and a quick connector. The heat dissipation copper tube is wrapped around the welding fixture and fixed to the welding fixture by brazing. The quick connector is connected to the water inlet and outlet of the heat dissipation copper tube via a threaded connection. The circulating heat dissipation water pump is connected to the heat dissipation copper tube via a compressed air PU tube and a quick connector, thereby providing cooling water to the heat dissipation copper tube. Due to the good thermal conductivity of brass, the heat generated during the venturi tube welding process will be transferred to the heat dissipation copper tube through the welding tooling, and finally carried away by the circulating water provided by the circulating heat dissipation water pump, so that the temperature of the welding tooling during the welding process does not exceed 300℃.

[0083] As an optional embodiment, the welding tool is made of brass or a copper alloy with a copper content exceeding 90%. The inner diameter of the main argon gas delivery channel of the welding tool is approximately 6-8mm, and its wall thickness is 3-5mm, ensuring that the welding tool is not too large and convenient for one-handed operation. The inner diameter of the argon gas uniform distribution channel in the middle part is approximately 3-4mm, and its wall thickness is 3-4mm. There are approximately 5-8 channels and they are evenly distributed on the welding tool. The thickness of the flange at the connection with the engine flame tube sleeve and splash plate is not less than 8mm and should not exceed 14mm. Otherwise, it is too thick and the welding tool is too heavy to be operated with one hand. The flange may be too thin, or the flange may soften due to heat accumulation caused by excessive heat conduction and slow heat conduction; the gap between the contoured arc surface of the welding tool that penetrates into the back of the venturi tube and the back of the venturi tube is between 0.3-0.5mm; the gap between the argon plug at the center of the welding tool and the inner hole of the venturi tube is between 0.4-0.7mm, and the former gap must be smaller than the latter. A gap of 1.5-2mm is left between the annular airway of the welding tool and the sleeve to facilitate the adjustment of the welding tool position so that the contoured arc surface of the welding tool fits the crack of the venturi tube as closely as possible, while also facilitating the entry of argon gas into the back of the venturi tube.

[0084] As an optional embodiment, the fluororubber sealing ring is installed on the annular groove of the welding tool by overfitting, and its thickness is 3-5mm; the installation height of the fluororubber sealing cavity can be level with the end face of the welding tool, or slightly higher, and its height does not exceed 1mm.

[0085] As an optional implementation method, the heat dissipation copper tube is made of brass tube with an inner diameter of about 4-6mm and a wall thickness of 1-2mm. The number of turns of the heat dissipation copper tube wrapped around the welding tool is not less than 8 turns and should not exceed 16 turns, otherwise the welding tool will be too long and difficult to operate with one hand.

[0086] As an optional implementation, the water supply pressure of the circulating water cooling water pump is not less than 0.25MPa, but not more than 1MPa (the compressed air PU pipe usually has a pressure resistance of no more than 1MPa), and the circulating water supply temperature is not higher than 28°C.

[0087] As an optional implementation, the inner diameter of the compressed air PU tube used to supply argon needs to be at least 1.1 times larger than the inner diameter of the main argon inlet pipe of the welding tooling to ensure the argon supply.

[0088] As an optional implementation, the measuring range of the argon flow meter is 0-25 L / min, and the measuring range of the argon pressure gauge is a high-precision pressure gauge with a measuring range of 0-15 kPa.

[0089] A device and method for repairing a venturi tube of a combustion chamber of a certain type of aviation turbofan engine comprises the following steps:

[0090] S1: Install the fluororubber sealing ring on the annular groove of the welding fixture, and fix the pressure plate and the welding fixture by tightening the bolts so that the fluororubber sealing ring can fit tightly with the sleeve and splash plate to form a relatively closed cavity on the back of the venturi tube.

[0091] S2: In the process of forming the relatively closed cavity, since there is a certain gap between the welding tool and the venturi tube, the position of the welding tool can be fine-tuned to make the welding tool fit the crack of the venturi tube as closely as possible.

[0092] S3: Use the compressed air PU tube and quick connector to quickly connect the argon cylinder, flow meter, pressure gauge, and welding tooling.

[0093] S4: Quickly connect the circulating water pump and the heat dissipation copper pipe through the compressed air PU pipe and quick connector, and turn on the circulating water pump.

[0094] S5: Open the argon gas bottle, set the nitrogen flow rate to 15-18 L / min, and the gas supply pressure to 4-8 KPa, so that a slight pressure is generated inside the cavity.

[0095] S6: Turn on the welding machine, set it to argon arc welding mode, and set the current to 60±5A.

[0096] S7: The argon filling time is 15s, so that the air in the back cavity of the venturi tube flows out from the cracks of the venturi tube and the gap between the inner hole of the venturi tube and the welding tooling, such as Figure 1 As shown by the dotted arrow in the figure, the cavity on the back of the venturi tube is filled with argon gas, which plays a protective role during the welding process.

[0097] S8: After 20 seconds, the welding machine is switched to the argon arc welding mode, and argon arc welding is used to weld on the positive surface of the venturi tube. The specification of the welding wire is HGH605, the diameter of the welding wire is 2.0-2.5 mm, and the welding time is about 30-60 seconds.

[0098] S9: After the welding is completed, pause for about 30 seconds. During this period, continue to supply argon gas and circulating water so that the venturi tube is still protected by argon gas during the cooling process and is not oxidized. At the same time, the circulating water removes the heat generated by welding on the venturi tube and the protective environment frame to prevent burns during disassembly.

[0099] S10: After welding is completed, remove the welding tool and use a grinder to grind the welding part of the venturi tube surface to make its surface smooth.

[0100] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, and the modifications are protected by patent law as long as they are within the scope of the claims of the present application.

Claims

1. A device for repairing a venturi tube of a combustion chamber of an aircraft engine, comprising a welding assembly (1), characterized in that: The repair device further comprises a cooling support protection component; during the welding repair process of the flame tube venturi tube (2), the welded portion of the flame tube venturi tube (2), the adjacent area connected to the welded portion, and the surrounding airspace are in a protective environment constructed by the cooling support protection component (5) and the sleeve (11) of the aircraft engine combustion chamber. The cooling support protection assembly (5) at least comprises a fixing assembly (3), a sealing assembly (4) and a protective environment construction system (6). The protective environment construction system (6) is detachably fixed to the flame tube venturi (2) to be repaired through the fixing assembly (3). The gap between the sleeve (11) and the protective environment construction system (6) is sealed by the sealing assembly (4). The protective environment construction system (6) includes a protective environment construction frame (7) and an argon gas conveying component group (8), a main argon gas conveying channel (7-1) is provided on the protective environment construction frame (7), a gas output end of the argon gas conveying component group (8) is connected to the main argon gas conveying channel (7-1), the protective environment construction frame (7) is detachably fixed on the flame tube venturi (2) to be repaired through the fixing component (3), and the sealing component (4) is cushioned at the gap between the sleeve (11) and the protective environment construction frame (7). The sealing assembly (4) is composed of a high-temperature resistant fluororubber sealing ring, and an annular groove (7-2-2) is provided at a corresponding position at one end of the protective environment frame (7). The aircraft engine combustion chamber also includes a splash plate (12). The fluororubber sealing ring filled in the annular groove (7-2-2) is exposed from the annular groove (7-2-2) and is connected to the end surface of the sleeve (11) and the splash plate (12) of the aircraft engine combustion chamber. The fixing assembly (3) includes a pressure plate (3-1) and a connecting bolt (3-2), the protective environment construction frame (7) is in a T-shaped structure, the main argon gas delivery channel (7-1) is arranged on the vertical side of the T-shaped protective environment construction frame (7), the environmental construction step (7-2) is composed of the horizontal side of the T-shaped protective environment construction frame (7), the flange (7-2-1) is arranged on the horizontal side of the environmental construction step (7-2), the annular groove (7-2-2) is arranged on the flange (7-2-1) of the environmental construction step (7-2), the column (7-2-3) is arranged at the center of the environmental construction step (7-2), and a vertical argon gas delivery channel is arranged inside the column (7-2-3). The argon uniformly distributed outlet duct (7-3) of the duct (7-1) is provided, and an outlet groove (7-4) extending in the circumferential direction and communicating with the argon uniformly distributed outlet duct (7-3) is provided at the root of the column (7-2-3), and the outlet groove (7-4), the flange (7-2-1), the side of the column (7-2-3) and the sleeve (11) and radial vortex flow device of the aircraft engine combustion chamber constitute the peripheral airspace; a threaded hole (7-8) is provided on the outer end surface of the column (7-2-3), and the protective environment construction frame (7) is detachably fixed on the flame tube venturi (2) that needs to be repaired through the pressure plate (3-1) in cooperation with the connecting bolt (3-2) and the threaded hole (7-8). An argon plug (7-5) is provided on the outer end surface of the column (7-2-3), and a contoured arc surface (7-6) extending in the circumferential direction is also provided on the outer end surface of the argon plug (7-5); an annular air passage (7-7) is also provided on the back of the contoured arc surface (7-6), and a threaded hole (7-8) is provided on the argon plug (7-5). The venturi crack (2-2) that needs to be repaired on the back arc surface (2-1) of the flame tube venturi is inserted into the contoured arc surface (7-6) of the protective environment construction frame (7) that is fixed in place.

2. The repair device for the venturi of the combustion chamber flame liner of an aircraft engine according to claim 1, characterized in that: The cooling support protection component (5) further includes a circulating heat dissipation cooling system (9), wherein the heat dissipation copper tube (9-1) of the circulating heat dissipation cooling system (9) is wound on the vertical side of the T-shaped protective environment frame (7), the number of turns of the heat dissipation copper tube (9-1) is 8-15, and the heat dissipation copper tube (9-1) is fixed to the protective environment frame (7) by brazing, and the water inlet and outlet of the heat dissipation copper tube (9-1) are respectively installed with quick connectors (10) through threaded connection structures, and the water pipe (9-2) of the circulating heat dissipation water cooling system (9) is quickly connected to the heat dissipation copper tube (9-1) through the threaded connection structure.

3. The repair device for the venturi of the combustion chamber flame liner of an aircraft engine according to claim 2, characterized in that: The protective environment frame (7) and the heat dissipation copper tube (9-1) are made of red copper or a copper alloy with a copper content of more than 90%. The inner diameter of the main argon gas delivery channel (7-1) is 6-8 mm and the wall thickness is 3-5 mm. The inner diameter of the argon gas uniform distribution outlet channel (7-3) in the middle part is 3-4 mm and the wall thickness is 3-5 mm. The number of the argon gas uniform distribution outlet channels (7-3) is 5-8 and they are evenly distributed. The thickness of the flange (7-2-1) at the connection with the engine flame tube sleeve and the splash plate is not less than 8 mm.

4. The repair device for the venturi of the combustion chamber flame liner of an aircraft engine according to claim 1, 2 or 3, characterized in that: A matching clearance of 0.3-0.5 mm is left between the arc surface (2-1) on the back of the flame tube venturi and the contoured arc surface (7-6), a matching clearance of 0.4-0.7 mm is left between the inner hole (2-3) of the venturi and the argon plug (7-5), and the gap of the former must be smaller than the gap of the latter, and a matching clearance of 1.5-2 mm is left between the annular gas channel (7-7) and the sleeve (11), and the welding assembly (1) is an argon arc welding machine.

5. A construction method for repairing a venturi tube in a combustion chamber of an aircraft engine using the repair device according to claim 4, characterized in that: The construction method comprises the following steps: 1) Installing the fluororubber sealing assembly (4) in the annular groove (7-2-2) of the protective environment frame (7), and fixing it to the threaded hole (7-8) on the protective environment frame (7) through the connecting bolts (3-2) and the pressure plate (3-1), so that the venturi tube (2) and the T-shaped protective environment frame (7) are fixed together, and the fluororubber sealing ring can be tightly fitted with the sleeve (11) and the splash plate (12), forming a closed cavity at the back of the venturi tube (2); 2) During the process of forming the closed cavity in step 1), the gap between the protective environment construction frame (7) and the venturi tube is finely adjusted so that the contoured arc surface fits the crack (2-2) of the venturi tube as closely as possible; 3) quickly connecting and assembling the argon gas delivery component assembly (8) through a quick connector (10); 4) Quickly connect the circulating heat dissipation water cooling system (9) through the quick connector (10), and start the circulating heat dissipation water cooling system (9); 5) Open the external argon gas bottle to create an argon gas protective environment; 6) Turn on the welding machine of the welding assembly (1) and set it to argon arc welding mode, and adjust the welding current to prepare for welding; 7) Inflate with argon for at least 15 seconds to exhaust the air between the back arc surface (2-1) of the Venturi tube and the imitation arc surface from the Venturi tube crack (2-2) and the gap between the argon plug (7-5) and the inner hole (2-3) of the Venturi tube. After the gap is filled with argon, argon arc welding is used to perform surfacing on the positive surface of the Venturi tube crack (2-2); 8) After the welding is completed, pause for about 30 seconds, during which time the argon gas and circulating water continue to be supplied; 9) Finally, remove the protective environment frame (7) and use a pneumatic grinder to grind the welding part of the venturi tube surface until its surface is smooth, completing the repair work. Among them, the model of the welding wire (1-1) during welding is HGH605, the diameter of the welding wire (1-1) is 2.0-2.5mm, and the welding time is about 30s-60s; the argon gas flow rate when constructing the argon gas protective environment is 15-18L / min, and the gas supply pressure is 4-8KPa; the cold water pressure of the circulating heat dissipation water cooling system (9) is not less than 0.25MPa and not higher than 1MPa, and the cold water temperature does not exceed 28°C; the refrigerant of the circulating heat dissipation water cooling system (9) can also use low-pressure compressed air, the pressure of the compressed air is not less than 0.4MPa and not higher than 1MPa, and the temperature does not exceed 25°C.

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