A piping arrangement structure for the high-pressure compressor rear casing of a small to medium-sized gas turbine.

Abstract

This invention relates to the field of gas turbine technology, specifically to a piping arrangement structure for the rear casing of a high-pressure compressor in a small to medium-sized gas turbine. To address the strength issues associated with welded or threaded connections for the exhaust pipe in conventional gas turbine rear casing layouts, this invention provides eight evenly distributed support slots on the outer ring of the high-pressure compressor rear casing. The lubricating oil supply pipe, air supply pipe, lubricating oil return pipe, and exhaust pipe are each fixedly connected to one support slot. The front of the high-pressure compressor rear casing is fixed to the front flange via multiple reinforcing ribs. A main flow channel is formed between the high-pressure compressor rear casing and the front flange. The lubricating oil supply pipe, air supply pipe, two lubricating oil return pipes, and four exhaust pipes are located within the notches of the front flange. During operation, high-temperature, high-pressure gas blows through the main flow channel. The medium flowing through the lubricating oil supply pipe, air supply pipe, lubricating oil return pipe, and exhaust pipe flows through the support slots and enters the high-pressure compressor rear casing for heat exchange. This invention is highly feasible, structurally sound, and highly safe.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, specifically to a piping arrangement structure of the high-pressure compressor rear casing of a small to medium-sized gas turbine. Background Technology

[0002] The commonly used arrangement of the rear casing of a gas turbine is as follows: Figure 1-2 As shown, the exhaust pipe uses a wall panel groove structure to draw gas out of the rear casing. The main drawback is its complex structure. Furthermore, the wall panel groove is fixed to the high-pressure compressor casing by welding. If defects occur on a large number of welded surfaces, the airtightness of the air supply pipe chamber cannot be guaranteed. Vibration and thermal expansion during unit operation will also affect the weld strength and sealing performance of the air supply pipe. If the lubricating oil supply pipe, lubricating oil return pipe, and air supply pipe in the rear casing piping layout are often connected using threaded structures, the strength at the connection points is weak, potentially leading to structural damage under gas turbine operating conditions.

[0003] In summary, both welding and threaded connections for the exhaust pipe present problems in the arrangement of the rear casing of the gas turbine. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the background technology. This invention provides a piping arrangement structure for the high-pressure compressor rear casing of a small and medium-sized gas turbine.

[0005] The objective of this invention is achieved as follows: a piping arrangement structure for the rear casing of a high-pressure compressor in a small to medium-sized gas turbine, characterized in that it includes a rear casing of a high-pressure compressor, a front flange, a lubricating oil supply pipe, a gas supply pipe, two lubricating oil return pipes, four exhaust pipes, and multiple reinforcing ribs.

[0006] Eight support slots are evenly distributed on the outer ring of the rear casing of the high-pressure compressor. The lubricating oil supply pipe, the air supply pipe, two lubricating oil return pipes, and four exhaust pipes are fixedly connected to one support slot. The front of the rear casing of the high-pressure compressor is fixed to the front flange through multiple reinforcing ribs. The space between the rear casing of the high-pressure compressor and the front flange forms the main flow channel. The outer ring of the front flange has eight notches. The lubricating oil supply pipe, the air supply pipe, the two lubricating oil return pipes, and the four exhaust pipes are located in one notch. During operation, high-temperature and high-pressure gas blows through the main flow channel. The medium flowing through the lubricating oil supply pipe, the air supply pipe, the two lubricating oil return pipes, and the four exhaust pipes flows through the support slots and enters the rear casing of the high-pressure compressor for heat exchange.

[0007] Furthermore, there are eight reinforcing ribs, which are evenly distributed along the circumference.

[0008] Furthermore, the acute angle formed by the axis of the lubricating oil supply pipe and the horizontal line is 33°45′.

[0009] Furthermore, two lubricating oil return pipes are located below the rear casing of the high-pressure compressor.

[0010] Furthermore, the axes of the lubricating oil supply pipe, the air supply pipe, the two lubricating oil return pipes, and the four exhaust pipes are all at an angle of 10° to the central axis of the rear casing of the high-pressure compressor.

[0011] Furthermore, the lubricating oil supply pipe includes an inner lubricating oil supply pipe, an outer lubricating oil supply pipe, a lubricating oil supply pipe boss, and a lubricating oil supply pipe insert.

[0012] The inner tube of the lubricating oil supply pipe is located inside the outer tube of the lubricating oil supply pipe, with a gap between them. The outer wall of the outlet end of the inner tube is welded to the inner wall of the outer tube. One end of the outer tube is inserted into one end of the lubricating oil supply pipe boss, and the connection between the outer wall of the outer tube and the boss is welded together. The insert of the lubricating oil supply pipe is connected to the other end of the boss and is integrally formed. The boss is welded to the rear casing of the high-pressure compressor. The insert of the lubricating oil supply pipe is inserted into the support groove with a gap between it and the support groove.

[0013] Furthermore, the lubricating oil return pipe includes an inner lubricating oil return pipe, an outer lubricating oil return pipe, a lubricating oil return pipe boss, and a lubricating oil supply pipe insert.

[0014] The inner tube of the lubricating oil return pipe is located inside the outer tube of the lubricating oil return pipe, with a gap between them. The end of the outer tube is fitted onto the outer wall of the inner tube. After one end of the inner tube is inserted into one end of the lubricating oil return pipe boss, the outer wall of the inner tube and the end of the lubricating oil return pipe boss are welded together in a complete circle. The lubricating oil supply pipe insert is welded to the other end of the lubricating oil return pipe boss. The lubricating oil return pipe boss is welded to the rear casing of the high-pressure compressor. The lubricating oil supply pipe insert is located in the support groove with a gap between it and the support groove.

[0015] Furthermore, the air supply pipe includes an inner air supply pipe, an outer air supply pipe, an air supply pipe boss, and an air supply pipe insert.

[0016] The inner tube of the air supply pipe is located inside the outer tube of the air supply pipe, with a gap between them. The end of the outer tube of the air supply pipe is fitted onto the outer wall of the inner tube. After one end of the inner tube is inserted into one end of the protrusion of the air supply pipe, the outer wall of the inner tube and the protrusion of the air supply pipe are welded together in a complete circle. The insertion tube of the air supply pipe is welded to the other end of the protrusion of the air supply pipe. The protrusion of the air supply pipe is welded to the rear casing of the high-pressure compressor. The insertion tube of the air supply pipe is located in the support groove and a gap is left between it and the support groove.

[0017] Furthermore, the exhaust pipe includes an exhaust pipe insert and an exhaust pipe boss;

[0018] After one end of the exhaust pipe insert is inserted into one end of the exhaust pipe boss, the outer wall of the exhaust pipe insert is welded around the junction with one end of the exhaust pipe boss, and the exhaust pipe boss is welded to the rear casing of the high-pressure compressor.

[0019] Furthermore, the rear part of the high-pressure compressor casing is provided with an inner wall plate and an outer wall plate;

[0020] The space between the inner and outer wall panels forms the outlet of the main channel.

[0021] Beneficial effects:

[0022] 1) This invention is part of the structure of a gas turbine and provides new ideas and design solutions for the development of gas turbines.

[0023] 2) The present invention has a simple structure and stable strength, which greatly reduces the time and difficulty of assembling the high-pressure compressor casing.

[0024] 3) This invention is highly feasible, has a reasonable structure, and is highly safe. It comprehensively considers the structure of each part of the gas turbine and the oil and gas system, and has a wide range of applications.

[0025] 4) This invention fully considers the requirements of different working fluids in the rear casing pipeline for normal operation in the gas turbine, and adopts a reasonable structure to ensure the physical properties of the working fluid, thereby ensuring the efficiency and safety of the gas turbine. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the commonly used arrangement of the rear casing of a gas turbine.

[0027] Figure 2 yes Figure 1 Schematic diagram of the exhaust pipe;

[0028] Figure 3 This is a front view of the piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to the present invention.

[0029] Figure 4 This is a rear view of the piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to the present invention.

[0030] Figure 5 This is a cross-sectional view of the lubricating oil supply pipe;

[0031] Figure 6 This is a cross-sectional view of the lubricating oil return pipe.

[0032] Figure 7 This is a cross-sectional view of the gas supply pipe;

[0033] Figure 8 This is a cross-sectional view of the exhaust pipe. Detailed Implementation

[0034] Specific implementation method 1: A pipeline arrangement structure of the high pressure compressor rear casing of a small and medium-sized gas turbine, which includes a high pressure compressor rear casing 8, a front flange 7, a lubricating oil supply pipe 1, an air supply pipe 4, two lubricating oil return pipes 6, four exhaust pipes 2 and multiple reinforcing ribs 5.

[0035] Eight support slots 3 are evenly distributed on the outer ring of the rear casing 8 of the high-pressure compressor. The lubricating oil supply pipe 1, the air supply pipe 4, the two lubricating oil return pipes 6 and the four exhaust pipes 2 are fixedly connected to one support slot 3 respectively. The front of the rear casing 8 of the high-pressure compressor is fixed to the front flange 7 through multiple reinforcing ribs 5. The space between the rear casing 8 of the high-pressure compressor and the front flange 7 forms the main channel 9. The outer ring of the front flange 7 has eight notches. The lubricating oil supply pipe 1, the air supply pipe 4, the two lubricating oil return pipes 6 and the four exhaust pipes 2 are located in one notch respectively. During operation, high-temperature and high-pressure gas blows through the main channel 9. The medium flowing through the lubricating oil supply pipe 1, the air supply pipe 4, the two lubricating oil return pipes 6 and the four exhaust pipes 2 flows through the support slots 3 and enters the rear casing 8 of the high-pressure compressor for heat exchange.

[0036] In this embodiment: the lubricating oil supply pipe facilitates the entry of external lubricating oil into the bearing at the central bearing housing of the unit. Under the action of gravity, the lubricating oil flows from top to bottom into the casing. Air is led out through the reducing joint at the outlet of the low-pressure compressor. The lubricating oil return pipe is used to recover the lubricating oil after it has played a lubricating role at the unit bearing. It is supplied to the casing of the high-pressure compressor rear casing through the air supply pipe for sealing and pressurization. Four exhaust pipes lead out the gas from the high-pressure compressor rear casing and deliver it to the second stage of the power turbine through external pipelines for sealing and pressurization. Optionally, two of the exhaust pipes are combined into one.

[0037] The circumferentially evenly arranged reinforcing ribs can enhance the strength and rigidity of the casing without increasing the casing wall thickness. On the other hand, they can avoid the problem of uneven stress caused by the difference in wall thickness between the inner and outer casings. Finally, they can also play an auxiliary positioning role when assembling the inner and outer casings.

[0038] Specific implementation method 2: A pipeline arrangement structure of the high-pressure compressor rear casing of a small and medium-sized gas turbine, wherein the number of reinforcing ribs 4 is eight, and the eight reinforcing ribs are evenly distributed along the circumferential direction.

[0039] Other implementation methods are the same as those in Specific Implementation Method 1.

[0040] Specific implementation method three: A pipeline arrangement structure for the high-pressure compressor rear casing of a small and medium-sized gas turbine, wherein the acute angle formed by the axis of the lubricating oil supply pipe 1 and the horizontal line is 33°45′.

[0041] In this embodiment: the lubricating oil supply pipe of the present invention is designed to facilitate the entry of external lubricating oil into the bearing at the central bearing seat of the unit. It needs to be arranged above the unit. Under the action of gravity, the lubricating oil flows from top to bottom into the casing. The acute angle formed by the central axis and the horizontal line is 33°45′. All other pipes are spaced 45° apart.

[0042] The lubricating oil supply pipe is located at the upper left, which facilitates the flow of oil in the lubricating oil supply pipe from top to bottom into the pipe inside the casing under the action of gravity.

[0043] Other implementation methods are the same as those in Specific Implementation Method 1.

[0044] Specific implementation method four: A pipeline arrangement structure for the rear casing of the high-pressure compressor of a small and medium-sized gas turbine, wherein two lubricating oil return pipes 6 are located below the rear casing 8 of the high-pressure compressor.

[0045] In this embodiment: the two oil return pipes are used to recover the lubricating oil after it has played a lubricating role at the unit bearing. These two oil return pipes need to be arranged below the unit so that the lubricating oil at the unit's central bearing can flow out of the casing along the oil return pipes under the action of gravity.

[0046] Other implementation methods are the same as those in Specific Implementation Method 1.

[0047] Specific implementation method five: A pipeline arrangement structure for the rear casing of the high-pressure compressor of a small and medium-sized gas turbine, wherein the axis of the lubricating oil supply pipe 1, the axis of the gas supply pipe 4, the axis of the two lubricating oil return pipes 6 and the axis of the four exhaust pipes 2 are all at an angle of 10° with the central axis of the rear casing 8 of the high-pressure compressor.

[0048] In this embodiment: the angle between all pipes and the horizontal central axis is 10°. Too small an angle with the central axis will prevent each pipe from avoiding the front flange in the axial direction, while too large an angle with the central axis will increase the radial dimension of the gas turbine and may cause interference with the combustion chamber shell outside the rear casing.

[0049] Other implementation methods are the same as those in Specific Implementation Method 1.

[0050] Specific implementation method six: A pipeline arrangement structure of the high pressure compressor rear casing of a small and medium-sized gas turbine, wherein the lubricating oil supply pipe 1 includes an inner lubricating oil supply pipe 1-1, an outer lubricating oil supply pipe 1-2, a lubricating oil supply pipe boss 1-3 and a lubricating oil supply pipe insert 1-4.

[0051] The inner tube 1-1 of the lubricating oil supply pipe is located inside the outer tube 1-2 of the lubricating oil supply pipe. There is a gap between the inner tube 1-1 and the outer tube 1-2 of the lubricating oil supply pipe. The outer wall of the outlet end of the inner tube 1-1 is welded to the inner wall of the outer tube 1-2 of the lubricating oil supply pipe. After one end of the outer tube 1-2 of the lubricating oil supply pipe is inserted into one end of the lubricating oil supply pipe boss 1-3, the outer wall of the outer tube 1-2 of the lubricating oil supply pipe and the end of the lubricating oil supply pipe boss 1-3 are welded together. The insert tube 1-4 of the lubricating oil supply pipe is connected to the other end of the lubricating oil supply pipe boss 1-3 and is integrally set. The lubricating oil supply pipe boss 1-3 is welded to the rear casing 8 of the high-pressure compressor. The insert tube 1-4 of the lubricating oil supply pipe is inserted into the support groove 3 and a gap is left between it and the support groove 3.

[0052] In this embodiment, the lubricating oil is supplied through the inner tube of the lubricating oil supply pipe. Its advantage is that it adopts a structure with inner and outer tube cavities. The lubricating oil temperature from the outer tube of the lubricating oil supply pipe is relatively low and should not exceed 50°C. The casing is close to the combustion chamber of the gas turbine, where the temperature is very high. Moreover, all the assembly components are made of metal and have good thermal conductivity. At this time, it is necessary to ensure that the thickness of the cavity reaches about 10mm.

[0053] The support slot is located in the main flow channel at the outlet of the high-pressure compressor. The air compressed by the low-pressure compressor and the high-pressure compressor has the characteristics of high temperature and high pressure, and the temperature can reach 500℃. In order to reduce the direct heat exchange between the air in the main flow channel and the lubricating oil supply pipe, a cavity is left between the air and the support slot.

[0054] In this invention, the outer and inner tubes of the lubricating oil supply pipe are fixedly connected by full-circle welding. The outer tube and the lubricating oil supply pipe boss are also fixedly connected by full-circle welding. Previously, the rear casing section often used threads for connection. Compared to threaded connections, welded connections significantly improve the strength of the connection, with weld strength reaching or even exceeding the strength of the base material, avoiding the weakness of threaded connections. Furthermore, welded structures offer better sealing than threaded structures, preventing working fluid leakage. Because the gas turbine experiences significant temperature differences between cold and rated operating conditions, to prevent cracking between components due to thermal expansion after welding, a gap of at least 1mm should be maintained between the inner and outer tube walls along the radial direction of the lubricating oil supply pipe. Additionally, due to the long axial length of the lubricating oil supply pipe, the deformation due to thermal expansion is substantial; therefore, a gap of approximately 3mm should be maintained between the outer tube and the inner cavity of the lubricating oil supply pipe boss. Meanwhile, since different metals have different coefficients of thermal expansion, in order to ensure the strength and stability of the welded structure, the inner tube, outer tube, and boss of the lubricating oil supply pipe of this invention should be made of the same metal material, namely, the high-strength alloy material 1Cr12Ni3MoVN with excellent heat resistance and corrosion resistance.

[0055] Other implementation methods are the same as those in Specific Implementation Method 1.

[0056] Specific implementation method seven: A pipeline arrangement structure of the high pressure compressor rear casing of a small and medium-sized gas turbine, wherein the lubricating oil return pipe 6 includes an inner lubricating oil return pipe 6-1, an outer lubricating oil return pipe 6-2, a lubricating oil return pipe boss 6-3, and a lubricating oil supply pipe insertion pipe 6-4.

[0057] The inner tube 6-1 of the lubricating oil return pipe is located inside the outer tube 6-2 of the lubricating oil return pipe. There is a gap between the inner tube 6-1 and the outer tube 6-2 of the lubricating oil return pipe. The end of the outer tube 6-2 of the lubricating oil return pipe is fitted onto the outer wall of the inner tube 6-1 of the lubricating oil return pipe. After one end of the inner tube 6-1 of the lubricating oil return pipe is inserted into one end of the lubricating oil return pipe boss 6-3, the outer wall of the inner tube 6-1 of the lubricating oil return pipe and one end of the lubricating oil return pipe boss 6-3 are welded together in a complete circle. The lubricating oil supply pipe insert 6-4 is welded to the other end of the lubricating oil return pipe boss 6-3. The lubricating oil return pipe boss 6-3 is welded to the rear casing 8 of the high-pressure compressor. The lubricating oil supply pipe insert 6-4 is located inside the support groove 3 and there is a gap between it and the support groove 3.

[0058] In this embodiment: due to the presence of the cavity between the inner and outer tubes, the heat conduction of the outer tube and the inner tube of the lubricating oil return pipe changes from solid metal heat conduction to gas heat conduction, which greatly reduces the thermal conductivity. The high temperature of the outer tube is not easily conducted to the inner tube, thereby ensuring a lower lubricating oil temperature in the inner tube.

[0059] The support slot is located in the main flow channel at the outlet of the high-pressure compressor. The air compressed by the low-pressure compressor and the high-pressure compressor has the characteristics of high temperature and high pressure, and the temperature can reach 500℃. In order to reduce the direct heat exchange between the air in the main flow channel and the lubricating oil return pipe, a cavity is left between the air and the support slot.

[0060] Other implementation methods are the same as those in Specific Implementation Method 1.

[0061] Specific implementation method eight: A pipeline arrangement structure of the high pressure compressor rear casing of a small and medium-sized gas turbine, wherein the gas supply pipe 4 includes an inner gas supply pipe 4-1, an outer gas supply pipe 4-2, a gas supply pipe boss 4-3, and a gas supply pipe insertion pipe 4-4.

[0062] The inner tube 4-1 of the air supply pipe is located inside the outer tube 4-2 of the air supply pipe. There is a gap between the inner tube 4-1 and the outer tube 4-2 of the air supply pipe. The end of the outer tube 4-2 of the air supply pipe is sleeved on the outer wall of the inner tube 4-1 of the air supply pipe. After one end of the inner tube 4-1 of the air supply pipe is inserted into one end of the protrusion 4-3 of the air supply pipe, the outer wall of the inner tube 4-1 of the air supply pipe and one end of the protrusion 4-3 of the air supply pipe are welded together in a circle. The other end of the protrusion 4-3 of the air supply pipe is welded to the other end of the protrusion 4-3 of the air supply pipe. The protrusion 4-3 of the air supply pipe is welded to the rear casing 8 of the high-pressure air compressor. The protrusion 4-4 of the air supply pipe is located in the support groove 3 and there is a gap between it and the support groove 3.

[0063] In this embodiment: The structure of the lubricating oil return pipe and the air supply pipe of the present invention is basically the same, the difference is that the working fluid inside is lubricating oil in one and compressed air in the other. The structure of inner and outer pipes is used to reduce the absorption of heat from the external environment by the lubricating oil inside the return pipe and the air from the low-pressure reducer inside the air supply pipe, thus ensuring a lower lubricating oil and air temperature.

[0064] Other implementation methods are the same as those in Specific Implementation Method 1.

[0065] Specific implementation method nine: A pipeline arrangement structure of the high pressure compressor rear casing of a small and medium-sized gas turbine, wherein the exhaust pipe 2 includes an exhaust pipe inlet 2-1 and an exhaust pipe boss 2-2.

[0066] After a section of the exhaust pipe insert 2-1 is inserted into one end of the exhaust pipe boss 2-2, the outer wall of the exhaust pipe insert 2-1 is welded to the end of the exhaust pipe boss 2-2 at the junction. The exhaust pipe boss 2-2 is then welded to the rear casing 8 of the high-pressure compressor.

[0067] In this embodiment: the exhaust pipe of the present invention is different from the lubricating oil pipe and the air supply pipe. The temperature of the compressed air inside the exhaust pipe is relatively high, and there is no need to worry about the influence of the external temperature on the exhaust temperature. A simple single-layer pipe structure is adopted.

[0068] Other implementation methods are the same as those in Specific Implementation Method 1.

[0069] Specific Implementation Method 10: A pipeline arrangement structure for the rear casing of a high-pressure compressor of a small and medium-sized gas turbine, wherein an inner wall plate 10 and an outer wall plate 11 are provided at the rear of the rear casing 8 of the high-pressure compressor.

[0070] The space between the inner wall panel 10 and the outer wall panel 11 forms the outlet of the main channel 9.

[0071] In this embodiment: the lubricating oil supply pipe boss, lubricating oil return pipe boss, air supply pipe boss, exhaust pipe boss, and support groove wall plate are inserted radially into the outer and inner wall plates of the component, pointing vertically downwards in the cross-section shown in the figure. Unlike the usual arrangement of pipes in the casing at a certain angle, the radial arrangement makes the structure of the rear casing more compact and reduces the axial size of the gas turbine. Since the lower end face of each boss and the upper end face of the high-pressure compressor rear casing are located in the main flow channel of the high-pressure compressor rear casing, in order to ensure the stability of the high-pressure airflow after passing through the guide vanes and the efficiency of the compressor, their shape should be completely consistent with the shape of the rear casing flow channel, and should not protrude more than 0.5mm from the main flow channel.

[0072] Other implementation methods are the same as those in Specific Implementation Method 1.

Claims

1. A piping arrangement structure for the high-pressure compressor rear casing of a small to medium-sized gas turbine, characterized in that: It includes a high-pressure compressor rear casing (8), a front flange (7), a lubricating oil supply pipe (1), an air supply pipe (4), two lubricating oil return pipes (6), four exhaust pipes (2) and multiple reinforcing ribs (5); Eight support slots (3) are evenly distributed on the outer ring of the rear casing (8) of the high-pressure compressor. The lubricating oil supply pipe (1), the air supply pipe (4), the two lubricating oil return pipes (6) and the four exhaust pipes (2) are fixedly connected to one support slot (3). The front of the rear casing (8) of the high-pressure compressor is fixedly connected to the front flange (7) through multiple reinforcing ribs (5). The space between the rear casing (8) of the high-pressure compressor and the front flange (7) forms the main channel (9). The outer ring of the front flange (7) is provided with eight notches. The lubricating oil supply pipe (1), the air supply pipe (4), the two lubricating oil return pipes (6) and the four exhaust pipes (2) are located in one notch. When working, the high-temperature and high-pressure gas blows through the main channel (9). The medium flowing through the lubricating oil supply pipe (1), the air supply pipe (4), the two lubricating oil return pipes (6) and the four exhaust pipes (2) flows through the support slots (3) and enters the rear casing (8) of the high-pressure compressor for heat exchange.

2. The piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to claim 1, characterized in that: The number of reinforcing ribs (5) is eight, and the eight reinforcing ribs are evenly distributed along the circumference.

3. The piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to claim 1, characterized in that: The acute angle formed by the axis of the lubricating oil supply pipe (1) and the horizontal line is 33°45′.

4. The piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to claim 1, characterized in that: Two lubricating oil return pipes (6) are located below the rear casing (8) of the high-pressure compressor.

5. The piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to claim 1, characterized in that: The axes of the lubricating oil supply pipe (1), the air supply pipe (4), the two lubricating oil return pipes (6), and the four exhaust pipes (2) are all 10° apart from the central axis of the high-pressure compressor rear casing (8).

6. The piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to claim 1, characterized in that: The lubricating oil supply pipe (1) includes an inner lubricating oil supply pipe (1-1), an outer lubricating oil supply pipe (1-2), a lubricating oil supply pipe boss (1-3), and a lubricating oil supply pipe insert (1-4); The inner tube (1-1) of the lubricating oil supply pipe is located inside the outer tube (1-2) of the lubricating oil supply pipe. A gap is left between the inner tube (1-1) and the outer tube (1-2). The outer wall of the outlet end of the inner tube (1-1) is welded to the inner wall of the outer tube (1-2) around its circumference. After a section of the outer tube (1-2) is inserted into one end of the lubricating oil supply pipe boss (1-3), the lubricating oil supply pipe... The outer wall of the outer tube (1-2) is welded to one end of the lubricating oil supply pipe boss (1-3) in a complete circle. The lubricating oil supply pipe insert (1-4) is connected to the other end of the lubricating oil supply pipe boss (1-3) and is integrally set. The lubricating oil supply pipe boss (1-3) is welded to the rear casing (8) of the high-pressure compressor. The lubricating oil supply pipe insert (1-4) is inserted into the support groove (3) and a gap is left between it and the support groove (3).

7. The piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to claim 1, characterized in that: The lubricating oil return pipe (6) includes an inner lubricating oil return pipe (6-1), an outer lubricating oil return pipe (6-2), a lubricating oil return pipe boss (6-3), and a lubricating oil supply pipe insert (6-4); The inner tube (6-1) of the lubricating oil return pipe is located inside the outer tube (6-2) of the lubricating oil return pipe. There is a gap between the inner tube (6-1) and the outer tube (6-2). The end of the outer tube (6-2) of the lubricating oil return pipe is fitted onto the outer wall of the inner tube (6-1). After one end of the inner tube (6-1) of the lubricating oil return pipe is inserted into one end of the lubricating oil return pipe boss (6-3), the outer wall of the inner tube (6-1) of the lubricating oil return pipe and one end of the lubricating oil return pipe boss (6-3) are welded together. The lubricating oil supply pipe insert (6-4) is welded to the other end of the lubricating oil return pipe boss (6-3). The lubricating oil return pipe boss (6-3) is welded to the rear casing (8) of the high-pressure compressor. The lubricating oil supply pipe insert (6-4) is located inside the support groove (3) and there is a gap between it and the support groove (3).

8. The piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to claim 1, characterized in that: The gas supply pipe (4) includes an inner gas supply pipe (4-1), an outer gas supply pipe (4-2), a gas supply pipe boss (4-3), and a gas supply pipe insert (4-4); The inner tube (4-1) of the air supply pipe is located inside the outer tube (4-2) of the air supply pipe. There is a gap between the inner tube (4-1) and the outer tube (4-2). The end of the outer tube (4-2) of the air supply pipe is sleeved on the outer wall of the inner tube (4-1). After one end of the inner tube (4-1) of the air supply pipe is inserted into one end of the protrusion (4-3) of the air supply pipe, the outer wall of the inner tube (4-1) of the air supply pipe is welded to the protrusion (4-3) of the air supply pipe at the junction. The other end of the air supply pipe insert (4-4) is welded to the protrusion (4-3) of the air supply pipe. The protrusion (4-3) of the air supply pipe is welded to the rear casing (8) of the high-pressure air compressor. The air supply pipe insert (4-4) is located inside the support groove (3) and there is a gap between it and the support groove (3).

9. The piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to claim 1, characterized in that: The exhaust pipe (2) includes an exhaust pipe insert (2-1) and an exhaust pipe boss (2-2); After one end of the exhaust pipe insert (2-1) is inserted into one end of the exhaust pipe boss (2-2), the outer wall of the exhaust pipe insert (2-1) is welded to the end of the exhaust pipe boss (2-2) at the junction. The exhaust pipe boss (2-2) is then welded to the rear casing (8) of the high-pressure compressor.

10. The piping arrangement structure of the high-pressure compressor rear casing of a small-to-medium-sized gas turbine according to claim 1, characterized in that: The rear part of the high-pressure compressor rear casing (8) is provided with an inner wall plate (10) and an outer wall plate (11); The space between the inner wall panel (10) and the outer wall panel (11) forms the outlet of the main channel (9).

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