Anti-knock igniter for an aeroengine

Abstract

This invention belongs to the field of aero-engines and discloses an explosion-proof igniter for aero-engines. It includes: an integrated housing, an upper ball seat, a lower ball seat, a hollow ball head, a baffle plate, a starting nozzle, and an ignition electrode. The integrated housing is cylindrical, with a blind hole on its lower end face, the bottom of which is spherical. The outer wall of the housing has external threads. A starting nozzle connector, an ignition electrode connector, and an oxygen supply pipe connector are respectively located on the upper side of the integrated housing. A starting nozzle and an ignition electrode are installed in the starting nozzle connector and the ignition electrode connector, respectively, and these connectors are connected to the bottom of the blind hole. The oxygen supply pipe connector connects to an oxygen supply line. The upper ball seat is cylindrical, with internal threads on its upper inner wall, and is connected to the integrated housing via these threads. The lower inner wall of the upper ball seat and the inner wall of the lower ball seat form a spherical surface that mates with the hollow ball head. An air intake groove is provided on the side wall of the upper ball seat. The baffle plate is welded inside the upper ball seat and located below the air intake groove.

Description

Technical Field

[0001] This invention belongs to the field of aero-engines, and relates to igniter structures, and more particularly to an explosion-proof igniter for aero-engines. Background Technology

[0002] The aircraft engine igniter adopts a pre-combustion igniter, which is an engine ignition device consisting of an igniter housing, a starting nozzle, and an ignition electrode. When working, it first ignites the oil-gas mixture inside the igniter to form a torch, and the torch ignites the oil-gas mixture in the entire flame tube.

[0003] The difference between a ground-based vehicle test igniter and a regular igniter is that the engine's own fuel and power supply devices are eliminated; instead, fuel and power are supplied directly from the test platform. The ground-based vehicle test igniter is designed for independent assembly and disassembly and should not interfere with the assembly and disassembly of the engine block. While a regular igniter only considers the connection with the combustion chamber housing and flame tube, the ground-based vehicle test igniter requires additional consideration of its compatibility with the engine's external bypass nozzle, i.e., a three-layer sealing structure.

[0004] Common ground test vehicle igniters and connection structures are shown below. Figure 1 The structure comprises: 1. Upper housing, constructed by argon arc welding of the igniter housing, starting nozzle connector, and ignition electrode connector; 2. Upper ball seat; 3. Lower ball seat; 4. Hollow ball head; 5. Baffle plate; 6. Starting nozzle; 7. Ignition electrode; 8. Asbestos tape; 9. Cover plate assembly, constructed by welding the cover plate and mounting base; 10. Upper sealing cover plate; 11. Lower sealing cover plate; 12. Outer nozzle; 13. Combustion chamber casing; and 14. Flame tube bushing. The upper housing 1, upper ball seat 2, and combustion chamber casing are bolted together. The upper housing 1 and cover plate assembly 8 are sealed with asbestos tape 7.

[0005] Traditional igniters, with their housing and ball joint assembly assembled as a single unit within the combustion chamber casing, impose stringent requirements on the design of the igniter's fit with the outer bypass nozzle. This necessitates six components: asbestos tape, a cover plate, an upper sealing cover plate, a lower sealing cover plate, a mounting base, and a welded ring on the upper housing. This complex design leads to difficult assembly and poor sealing during testing. Applying sealant to leaks yields minimal results and further complicates post-test disassembly. Furthermore, the lack of an oxygen supply device prevents the simulation of high-altitude ignition. Summary of the Invention

[0006] Purpose of the invention: To provide an explosion-proof igniter for aero engines, which reduces the difficulty of igniter assembly and sealing issues, improves the ignition margin of the igniter, extends the life of the igniter, and thus ensures engine performance and reduces manufacturing costs.

[0007] The technical solution of this invention is:

[0008] An explosion-proof igniter for an aircraft engine includes: an integrated housing, an upper ball seat, a lower ball seat, a hollow ball head, a baffle, an ignition nozzle, and an ignition electrode.

[0009] The integrated housing is cylindrical, with a blind hole on the lower end face of the housing, and the bottom of the blind hole is spherical; the outer wall of the housing is provided with external threads;

[0010] The upper side of the integrated housing is provided with a starting nozzle connector, an ignition nozzle connector, and an oxygen supply pipe connector; a starting nozzle and an ignition nozzle are respectively installed in the starting nozzle connector and the ignition nozzle connector; and the starting nozzle connector and the ignition nozzle connector are connected to the bottom of the blind hole; the oxygen supply pipe connector is connected to the oxygen supply pipeline.

[0011] The upper ball seat is cylindrical, and the inner wall of the upper ball seat is provided with internal threads. The upper ball seat is connected to the integral shell through the threads.

[0012] The inner wall below the upper ball seat and the inner wall of the lower ball seat form a spherical surface that fits and connects with the hollow ball head.

[0013] The upper ball seat has an air inlet groove on its side wall; the baffle is welded inside the upper ball seat and located below the air inlet groove.

[0014] Furthermore, the igniter is connected to the outer duct nozzle via a cover plate assembly;

[0015] The cover plate assembly is a plate-shaped structure that matches the shape of the outer bypass nozzle;

[0016] The cover plate assembly has a through hole; a sealing ring is welded to the inner wall of the through hole;

[0017] The outer wall of the upper ball seat is provided with a sealing ring mounting groove; an O-ring is installed in the sealing ring mounting groove; and the connection between the igniter and the cover plate assembly is achieved by squeezing the O-ring with a sealing ring.

[0018] Furthermore, the outer wall of the integrated housing is a cylindrical surface with two different diameters, and the diameter of the upper end is larger than that of the lower end; the outer wall of the lower cylindrical surface of the integrated housing is provided with an external thread and screwed to the upper ball seat;

[0019] An adjustment shim is provided between the stepped surface of the outer wall of the integrated housing and the upper end face of the upper ball seat; by adjusting the thickness of the adjustment shim, the relative position of the baffle and the starting nozzle is adjusted, and at the same time the height of the flow field inside the igniter is adjusted to increase the ignition success rate.

[0020] Furthermore, the outer wall of the upper ball seat is provided with an annular flange, which is bolted to the combustion chamber casing.

[0021] Furthermore, the upper ball seat and the lower ball seat are welded by argon arc welding; during assembly, the hollow ball head is first installed in the lower ball seat, and then the lower ball seat and the upper ball seat are welded by segmented argon arc welding.

[0022] Furthermore, the segmented argon arc welding is divided into multiple segments, each with a weld length of 3mm to 10mm.

[0023] Furthermore, the outer surface of the hollow ball head and the inner surfaces of the upper and lower ball seats are in clearance fit, with a clearance of 0.2mm to 0.35mm.

[0024] Furthermore, the oxygen supply pipe connector is equipped with a one-way valve to prevent oil and gas backflow.

[0025] Furthermore, the diameter of the connection between the bottom of the starting nozzle connector and the bottom of the blind hole of the integrated housing is not less than the diameter of the starting nozzle connector.

[0026] Furthermore, the oxygen supply pipe connector is angled and positioned on the front of the integrated housing, communicating with the inner wall of the starting nozzle connector.

[0027] The present invention has the following beneficial effects:

[0028] The integrated shell structure effectively avoids flow field distortion caused by welding.

[0029] The oxygen supply pipe connector is located on top of the integrated housing, and the starting nozzle connector is located on the side above the integrated housing. That is, the starting nozzle is lower than the oxygen supply pipe to prevent oil from flowing into the oxygen supply pipe and causing deflagration.

[0030] A one-way valve is added upstream of the oxygen supply pipe connector. When the engine is started at high altitude, the one-way valve is in the open position, providing a passage and operating normally. After ignition is completed and oxygen supply is cut off, the one-way valve closes momentarily due to the engine pressure difference, blocking fuel and air from flowing into the oxygen supply pipe from the electric igniter, effectively ensuring the pipe is sealed and preventing deflagration.

[0031] The inner diameter of the starting nozzle connector is fixed, and the part that mates with the bottom hole is straight, without steps or tapering structures, thus avoiding the problem of oil accumulation in the cavity of traditional igniters.

[0032] The adjusting pad serves two purposes: first, it ensures the relative position of the baffle plate and the starting nozzle assembly; second, it allows for flexible adjustment of the height of the flow field inside the igniter, greatly increasing the ignition success rate.

[0033] The clearance fit between the upper side of the hollow ball head and the upper and lower ball seats, and the clearance fit between the lower side and the flame tube bushing, allow for axial and circumferential movement, increasing assembly reliability.

[0034] The ignition device of this invention has a small number of components, and the matching cover plate assembly has a simple structure and is easy to assemble, which effectively reduces the processing cost of the ignition device. The one-way valve structure avoids the detonation problem that is prone to occur when the engine is started multiple times. The ignition device has a good sealing effect and effectively improves the engine performance. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the background technology of this invention;

[0036] Figure 2 This is a schematic diagram of the structure of an embodiment of the present invention;

[0037] Figure 3 for Figure 2 Side view;

[0038] Figure 4 for Figure 2 Top view;

[0039] Figure 5 for Figure 2 A magnified view of a portion of the image.

[0040] 1—Integrated housing, 2—Upper ball seat, 3—Lower ball seat, 4—Hollow ball head, 5—Baffle plate, 6—Starting nozzle, 7—Ignition nozzle schematic structure, 8—Adjusting pad, 9—Cover plate assembly, 10—O-ring seal, 11—Outer bypass nozzle, 12—Combustion chamber casing, 13—Flame tube bushing, 14—One-way valve schematic structure. Detailed Implementation

[0041] This section describes embodiments of the present invention, used to explain and illustrate the technical solutions of the present invention.

[0042] Example 1

[0043] An explosion-proof igniter for an aircraft engine includes: an integrated housing, a ball joint assembly, an adjusting pad, a starting nozzle, and an ignition electrode.

[0044] The integrated housing 1 consists of a housing 21, a starting nozzle connector 22, an oxygen supply pipe connector 23, and an electric nozzle connector 24. The starting nozzle connector is connected to the starting nozzle, the oxygen supply pipe connector is connected to the one-way valve and the oxygen supply pipe, and the electric nozzle connector is connected to the electric nozzle.

[0045] The outer wall of the integrated shell is composed of two cylindrical surfaces with different diameters, and the diameter of the upper cylinder is larger than that of the lower cylinder; the lower end of the outer wall is provided with external threads; a blind hole is opened on the lower end face of the shell, and the bottom of the blind hole is spherical.

[0046] The starting nozzle connector and the electric nozzle connector are located on the upper side of the housing, with a circumferential angle of 90° between them; the oxygen supply pipe connector is obliquely located on the top of the housing, with its bottom connecting to the starting nozzle connector. The bottoms of both the oxygen supply pipe connector and the electric nozzle connector communicate with the blind hole in the housing.

[0047] The ball head assembly consists of an upper ball seat, a lower ball seat, a hollow ball head, and a baffle.

[0048] The upper ball seat has an internal thread on its inner side wall, which is connected to the integrated housing through the thread. A graded adjustment pad is installed in the middle as needed. The side wall has an air inlet groove. The baffle is welded inside the upper ball seat and located below the air inlet groove.

[0049] The inner sidewall below the upper ball seat and the inner sidewall of the lower ball seat form a spherical surface that is connected to the hollow ball head with a gap fit.

[0050] The cover plate assembly consists of a cover plate and a sealing ring. It is a plate-shaped structure that matches the shape of the outer bypass nozzle and serves as a sealing connection between the igniter and the outer bypass nozzle.

[0051] The upper part of the outer side wall of the upper ball seat is provided with a sealing ring mounting groove; an O-ring is installed in the sealing ring mounting groove.

[0052] The sealing ring compresses the O-ring, and the two make surface contact, thus achieving a sealed connection between the igniter and the cover plate assembly.

[0053] The cover plate is provided with threaded holes around its circumference, and is connected with bolts to achieve a sealed fit with the outer duct nozzle.

[0054] The ball head assembly of the igniter is bolted to the combustion chamber housing, with three-point positioning.

[0055] Example 2

[0056] An anti-detonation igniter structure for an aircraft engine includes a baffle plate 5 argon arc welded to the lower part of the air intake slot of the upper ball seat 2; a hollow ball head 4 is assembled from directly above the lower ball seat 3, and after assembly, the upper ball seat 2 and the lower ball seat 3 are argon arc welded together. The argon arc welding is performed in three sections, each with a weld length of 5mm. After welding, the ball head assembly is complete. A one-way valve 14 is installed at the oxygen supply pipe joint to prevent deflagration.

[0057] The segmented welding mainly considers two points: segmented welds can effectively reduce the probability of weld material flowing to the hollow ball head 4; segmented welds have lower stress, and the hollow ball head 4 is in clearance fit with the upper ball seat 2 and the lower ball seat 3, with a fit clearance of 0.2mm-0.35mm. Excessive welding deformation can easily cause the hollow ball head to jam between the hollow ball head and the two ball seats, making it unable to rotate or shift flexibly, which affects the assembly with the flame tube.

[0058] After the engine is mounted on the test bench, the ball joint assembly is first installed at the combustion chamber housing 12 mounting seat, and the bolts are tightened. At this point, the hollow ball head 4 extends precisely into the flame tube bushing 13, completing the clearance fit between the two. Then, the cover plate assembly 9 is bolted and installed onto the outer bypass nozzle 11. When the assembly is completed, the sealing fit between the cover plate assembly mounting seat and the upper ball seat is simultaneously completed. After the cover plate assembly 9 is installed, the adjusting shims 8 are installed as needed. Finally, the one-piece housing is screwed into the ball joint assembly. When screwing it in, the number and grade of the adjusting shims are selected according to the circumferential position of the two. The igniter for ground testing is then assembled.

[0059] The airflow from the combustion chamber casing enters the igniter through the intake slot of the upper ball seat 2. Under the action of the baffle 5, it flows into the integrated housing 1 and mixes with the oil mist sprayed from the starting nozzle 6 and the oxygen sprayed from the oxygen supply nozzle 7. The upper part of the flow field inside the integrated housing 1 has a spherical structure, which forms a reflux zone to ensure sufficient mixing of oil, air and oxygen. The power supply time of the ignition electrode 7 is the same as the fuel supply time of the starting nozzle 6. The ignition electrode 7 releases an electric spark to ignite the oil-air mixture inside the igniter. The flame is transmitted to the inside of the flame tube in the direction of the hollow ball head 4, and the engine is successfully ignited.

[0060] This invention provides a structure for an anti-explosion igniter for an aero-engine. An oxygen supply connector ensures the igniter can simulate high-altitude ignition. A one-way valve connects to the outlet of the oxygen supply pipe connector, effectively ensuring the sealing of the oxygen supply line and preventing igniter explosion. The integrated housing 1 is a single unit, avoiding changes in flow field performance caused by welding deformation. After the outer bypass nozzle 11 and cover plate assembly are assembled, the integrated housing is connected to the upper ball seat 2 via a threaded connection, effectively reducing the structural complexity, processing, and assembly difficulty of the cover plate assembly. Adjustment shims 8 are optionally installed between the two. By selecting the number and grade of adjustment shims 8, the circumferential fit angle between the baffle 5 and the starting nozzle assembly 6 is ensured, and the height of the flow field inside the igniter can be flexibly adjusted, increasing the ignition success rate. The ball head assembly and the cover plate assembly 9 are sealed by surface contact using O-rings 10.

Claims

1. An explosion-proof igniter for an aircraft engine, characterized in that: The igniter includes: an integrated housing, an upper ball seat, a lower ball seat, a hollow ball head, a baffle plate, a starting nozzle, and an ignition electrode; The one-piece housing is cylindrical, with a blind hole on the lower end face of the housing, and the bottom of the blind hole is spherical; the outer wall of the housing is provided with external threads; The integrated housing has a starting nozzle connector, an ignition nozzle connector, and an oxygen supply pipe connector on its upper side. The starting nozzle connector and ignition nozzle connector respectively house the starting nozzle and ignition nozzle connectors, which are connected to the bottom of the blind hole. The oxygen supply pipe connector connects to the oxygen supply pipeline. The outer wall of the integrated housing consists of two cylindrical surfaces with different diameters, the upper diameter being larger than the lower diameter. The lower cylindrical surface of the integrated housing has an external thread that connects to the upper ball seat. An adjusting shim is provided between the stepped surface of the outer wall of the integrated housing and the upper surface of the upper ball seat. The thickness of the adjusting shim is adjusted to regulate the relative position of the baffle plate and the starting nozzle, and simultaneously adjusts the height of the flow field inside the igniter to increase the ignition success rate. The diameter at the connection between the bottom of the starting nozzle connector and the bottom of the blind hole in the integrated housing is not less than the diameter of the starting nozzle connector. The oxygen supply pipe connector is obliquely positioned on the front side of the integrated housing and connects to the inner wall of the starting nozzle connector. The upper ball seat is cylindrical, and the inner wall of the upper ball seat is provided with internal threads. The upper ball seat is connected to the integral housing through the threads. The inner wall below the upper ball seat and the inner wall of the lower ball seat form a spherical surface that fits into the hollow ball head; the outer surface of the hollow ball head and the inner surfaces of the upper and lower ball seats are in clearance fit. The upper ball seat has an air inlet groove on its side wall; the baffle plate is welded inside the upper ball seat and located below the air inlet groove; The igniter is connected to the outer duct nozzle via a cover plate assembly; the cover plate assembly is a plate-shaped structure that matches the shape of the outer duct nozzle; the cover plate assembly has a through hole; a sealing ring is welded to the inner wall of the through hole; a sealing ring mounting groove is provided on the outer wall of the upper ball seat; an O-ring is installed in the sealing ring mounting groove; and the connection between the igniter and the cover plate assembly is achieved by the sealing ring pressing the O-ring.

2. The igniter according to claim 1, characterized in that: The outer wall of the upper ball seat is provided with an annular flange, which is connected to the combustion chamber casing by bolts.

3. The igniter according to claim 2, characterized in that: The upper ball seat and the lower ball seat are welded by argon arc welding; during assembly, the hollow ball head is first installed in the lower ball seat, and then the lower ball seat and the upper ball seat are welded by segmented argon arc welding.

4. The igniter according to claim 3, characterized in that: The segmented argon arc welding is divided into multiple segments, each with a weld length of 3mm to 10mm.

5. The igniter according to claim 4, characterized in that: The clearance between the outer surface of the hollow ball head and the inner surfaces of the upper and lower ball seats is 0.2mm~0.35mm.

6. The igniter according to claim 5, characterized in that: The oxygen supply pipe connector is equipped with a one-way valve to prevent oil and gas backflow.

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