A reliable ignition device for heavy-duty gas turbines

Abstract

The present invention proposes a reliable heavy-duty gas turbine ignition device, including an ignition device positive terminal, a ceramic insulator, an ignition device center guide rod, an ignition seat gland, an ignition device cylindrical body, a brush-type sealing structure, a brush wire bundle, an ignition negative electrode, an ignition positive electrode, a spring, a pressure chamber, a base, and an ignition cable. The present invention designs a circle of brush-type sealing structure around the periphery of the ignition device center guide rod, and utilizes the unevenness of the gaps between the brush wires in the brush-type sealing structure to disrupt the direction of the uniform incoming airflow, so that the airflow is deflected from the tight brush wire bundle area to the loose brush wire bundle area. These deflected flows gradually form co-directional flows and jets between the brush wire rows, and generate random secondary flows and vortex flows. When the jet encounters a tight brush wire bundle, it will change its movement direction and become a lateral flow perpendicular to the mainstream direction, so that the fluid produces a self-sealing effect, achieving a sealing effect to prevent high-temperature gas from leaking from the ignition device.

Description

Technical Field

[0001] The invention relates to an ignition device, in particular to an ignition device suitable for a heavy-duty gas turbine. Background Art

[0002] A gas turbine is an advanced and complex set of power machinery equipment. Its working principle is basically the same as that of an aircraft engine. It converts the chemical energy of the fuel into the thermal energy and potential energy of the gas, and then uses the gas to drive the turbine to expand and do work. As a new generation of power devices after steam turbines and internal combustion engines, gas turbines have developed rapidly since their advent in the early 20th century, especially in the field of power generation. Gas turbine power generation technology has the characteristics of fast start-up, high efficiency, low pollution, small size, compact structure, short construction period, and fast results. At present, heavy-duty gas turbines are mostly used for peak load regulation of power grids, which require frequent starts and stops. Ignition is a key step in the start-up process of gas turbines.

[0003] Gas turbine ignition is a complex process involving the gas turbine body, auxiliary systems, control protection, etc. After the gas turbine ignition fails, it needs to be cleaned for a long time before entering the ignition procedure again. In-service heavy-duty gas turbines have the problem of high-temperature gas leaking from the ignition device and burning the ignition cable, resulting in the failure of the gas turbine to start, so that the gas turbine generator set cannot be started on time according to the requirements of the power grid, causing economic losses to the gas turbine power plant. Therefore, a reliable gas turbine ignition device is crucial to the normal startup of the gas turbine, which directly affects the economic benefits and peak-shaving flexibility of the unit. Summary of the invention

[0004] In order to solve the problem of high-temperature gas leakage from the ignition device of the gas turbine and prevent the ignition cable of the gas turbine ignition device from being burned, the present invention proposes a reliable heavy-duty gas turbine ignition device. The present invention designs a circle of brush-type sealing structure around the central guide rod of the ignition device, and utilizes the unevenness of the gaps between the brush wires in the brush-type sealing structure to disrupt the direction of the uniform incoming airflow, so that the airflow is deflected from the tight brush wire bundle area to the loose brush wire bundle area. These deflected flows gradually form co-directional flows and jets between the brush wire rows, and generate random secondary flows and vortex flows. When the jet encounters a tight brush wire bundle, it will change its direction of movement and become a lateral flow perpendicular to the mainstream direction, so that the fluid produces a self-sealing effect, achieving a sealing effect to prevent high-temperature gas from leaking from the ignition device.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] A reliable heavy-duty gas turbine ignition device comprises an ignition device positive terminal, a ceramic insulator, an ignition device center guide rod, an ignition seat gland, an ignition device cylindrical body, a brush seal structure and a spring;

[0007] The positive terminal of the ignition device is located in the center of the ignition device, the upper part is connected to the ignition cable, and the lower part is connected to the ignition positive electrode, and is used to conduct high voltage current;

[0008] The ceramic insulator is located at the periphery of the positive terminal of the ignition device and is arranged coaxially with the positive terminal of the ignition device, and is used to prevent discharge between the positive terminal of the ignition device and the central guide rod of the ignition device;

[0009] The central guide rod of the ignition device is located outside the ceramic insulator, the lower end of which is connected to the ignition negative electrode and arranged coaxially with the ceramic insulator to drive the ignition positive electrode and the ignition negative electrode to move up and down;

[0010] The ignition seat pressure cover is located at the uppermost part of the ignition device and is coaxially arranged with the central guide rod of the ignition device;

[0011] The cylindrical body of the ignition device is a hollow cylindrical cavity, the upper end surface of which is connected to the ignition seat cover, and the lower part is connected to the base;

[0012] The main body of the brush seal structure is a cylindrical cavity structure with a closed bottom and an open top. A circle of brush bundles is arranged on the periphery of the cylindrical cavity structure and is evenly arranged on the outer wall of the cylindrical cavity. The bottom of the brush seal structure is fixedly sleeved on the central guide rod of the ignition device.

[0013] The spring is sleeved on the central guide rod of the ignition device on the upper part of the brush seal structure;

[0014] The lower part of the brush seal structure, the cylindrical cavity and the base form a pressure chamber with variable size.

[0015] A further improvement of the present invention is that the shape of the positive electrode terminal of the ignition device is a cylindrical structure.

[0016] A further improvement of the present invention is that the ceramic insulator is in the shape of a cylindrical structure.

[0017] A further improvement of the present invention is that the ignition seat pressure cover is a cylindrical thin plate structure.

[0018] A further improvement of the present invention is that cover plate through holes for pressing the ignition seat cover are designed at equal intervals on the ignition seat cover.

[0019] A further improvement of the present invention is that a brush-type sealing structure is designed on the central guide rod of the ignition device.

[0020] A further improvement of the present invention is that the brush filament bundle is composed of densely arranged thin metal wires, and the material is a high-temperature alloy material.

[0021] A further improvement of the present invention is that the lower part of the brush bundle is a brush-type sealing front plate with an annular thin plate structure, and the upper part is a brush-type sealing back plate with an annular thin plate structure.

[0022] A further improvement of the present invention is that the ignition cathode is an L-shaped narrow-band thin-sheet structure made of high-temperature alloy material, and forms a high-voltage discharge with the ignition cathode located in the center during ignition to ignite the combustible mixture in the gas turbine combustion chamber.

[0023] A further improvement of the present invention is that during ignition, the gas pressure in the pressure chamber is relatively small, and the central guide rod of the ignition device is pushed downward by the action of the spring, and the ignition positive electrode and the ignition negative electrode extend into the combustion chamber for ignition. After successful ignition, the compressor speed gradually increases, and the compressor exhaust pressure also gradually increases, causing the gas pressure in the pressure chamber to increase. When the gas pressure in the pressure chamber is greater than the spring force, the central guide rod of the ignition device gradually moves upward, and the ignition positive electrode and the ignition negative electrode withdraw from the combustion chamber to prevent them from being burned by high-temperature fuel gas.

[0024] The present invention has at least the following beneficial technical effects:

[0025] The present invention provides a reliable heavy-duty gas turbine ignition device. The brush sealing method is used to design the periphery of the central guide rod of the ignition device located at the center of the ignition device into a brush sealing structure. Under the action of the unevenness of the gaps between the brush wires, when the gas flows through the brush sealing structure, the uniform incoming flow will be disturbed and become uneven. The airflow forms a strong self-sealing effect in the brush wire bundle, which can effectively prevent the leakage of high-temperature gas, prevent the ignition cable from burning, reduce the occurrence of ignition failures when the gas turbine is started, reduce the startup cost of the gas turbine, and improve the economic benefits of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a central cutaway view of a reliable heavy-duty gas turbine ignition device during ignition according to the present invention.

[0027] Figure 2 It is an isometric diagram of a reliable heavy-duty gas turbine ignition device of the present invention.

[0028] Figure 3 A central cutaway view of a reliable heavy-duty gas turbine ignition device after exiting a combustion chamber according to the present invention.

[0029] Description of reference numerals:

[0030] 1. Ignition device positive terminal; 2. Ceramic insulator; 3. Ignition device center guide rod; 4. Ignition seat pressure cover; 5. Ignition device cylindrical body; 6. Brush seal structure; 7. Brush wire bundle; 8. Brush seal front plate; 9. Brush seal back plate; 10. Ignition negative electrode; 11. Ignition positive electrode; 12. Spring; 13. Bolt hole; 14. Cover plate through hole; 15. Mounting bolt hole; 16. Pressure chamber; 17. Base; 18. Ignition cable. DETAILED DESCRIPTION

[0031] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] See also Figure 1 , Figure 2 and Figure 3 The present invention provides a reliable heavy-duty gas turbine ignition device, which mainly includes an ignition device positive electrode terminal 1, a ceramic insulator 2, an ignition device center guide rod 3, an ignition seat pressure cover 4, an ignition device cylindrical body 5, a brush seal structure 6, a brush wire bundle 7, a brush seal front plate 8, a brush seal back plate 9, an ignition cathode 10, an ignition anode 11, a spring 12, a bolt hole 13, a cover plate through hole 14, a mounting bolt hole 15, a pressure chamber 16, a base 17 and an ignition cable 18, etc.

[0033] The positive terminal 1 of the ignition device is located in the center of the ignition device and is cylindrical in shape. The upper part is connected to the ignition cable 18 and the lower part is connected to the ignition positive electrode 11 for conducting high voltage current.

[0034] The ceramic insulator 2 is located outside the positive terminal 1 of the ignition device, has a cylindrical structure, and is coaxially arranged with the positive terminal 1 of the ignition device to prevent discharge between the positive terminal 1 of the ignition device and the central guide rod 3 of the ignition device.

[0035] The central guide rod 3 of the ignition device is located outside the ceramic insulator 2, and the lower end is connected to the ignition cathode 10. It is cylindrical in shape and arranged coaxially with the ceramic insulator 2 to drive the ignition anode 11 and the ignition cathode 10 to move up and down.

[0036] The ignition seat cover 4 is a cylindrical thin plate structure, located at the top of the ignition device, and arranged coaxially with the central guide rod 3 of the ignition device. Cover plate through holes 14 for pressing the ignition seat cover 4 are designed at equal intervals on the ignition seat cover 4.

[0037] The ignition device cylindrical body 5 is a hollow cylindrical cavity, the upper end surface of which is connected to the ignition seat cover 4, and the lower part is connected to the base 17.

[0038] The main body of the brush seal structure 6 is a cylindrical cavity structure with a closed bottom and an open top. A circle of brush bundles 7 is arranged on the periphery of the cylindrical cavity structure. The brush bundles 7 are composed of densely arranged fine metal wires, and the material is a high-temperature alloy material, which is evenly arranged on the outer wall of the cylindrical cavity. The lower part of the brush bundle 7 is a brush seal front plate 8 with an annular thin plate structure, and the upper part is a brush seal back plate 9 with an annular thin plate structure. The brush seal structure 6 can destroy the uniform flow of the airflow, forming a chaotic and disordered flow, so that the fluid produces a self-sealing effect, forming a large damping to achieve a sealing effect to prevent high-temperature gas leakage.

[0039] The ignition cathode 10 is an L-shaped narrow thin-strip structure made of high-temperature alloy material, and forms a high-voltage discharge with the ignition anode 11 located in the center during ignition to ignite the combustible mixed gas in the combustion chamber of the gas turbine.

[0040] The spring 12 is installed on the central guide rod 3 of the ignition device. During ignition, the gas pressure in the pressure chamber 16 is relatively small. Under the action of the spring 12, the central guide rod 3 of the ignition device is pushed downward, and the ignition positive electrode 11 and the ignition negative electrode 10 extend into the combustion chamber for ignition. After the ignition is successful, the compressor speed gradually increases, and the compressor exhaust pressure also gradually increases, causing the gas pressure in the pressure chamber 16 to increase. When the gas pressure in the pressure chamber 16 is greater than the elastic force of the spring 12, the central guide rod 3 of the ignition device gradually moves upward, and the ignition positive electrode 11 and the ignition negative electrode 10 withdraw from the combustion chamber to prevent them from being burned by high-temperature fuel gas.

[0041] Example

[0042] See also Figure 1In this embodiment, the positive terminal 1 of the ignition device has a diameter of 2mm and a length of 202mm, and is located in the center of the ignition device; the ceramic insulator 2 has an inner diameter of 2mm, an outer diameter of 6mm, and a length of 192mm, and is arranged coaxially with the positive terminal 1 of the ignition device, and the lower end face of the ceramic insulator 2 is 5mm away from the ignition positive electrode 9; the inner diameter of the central guide rod 3 of the ignition device is 6mm, the outer diameter is 10mm, and the length is 197mm, and it is arranged coaxially with the ceramic insulator 2, and the upper end face of the central guide rod 3 of the ignition device is flush with the ceramic insulator 2; the inner diameter of the ignition seat pressure cover 4 is 10mm, the outer diameter is 52mm, and the thickness is 8mm. Eight cover plate through holes 14 with a diameter of 5.5mm are opened at equal intervals on a circle with a diameter of 44mm. The ignition seat pressure cover 4 is located at the uppermost part of the ignition device and is arranged coaxially with the central guide rod 3 of the ignition device; The inner diameter of the cylindrical body 5 of the ignition device is 36mm, the outer diameter is 52mm, and the length is 122mm. The upper end face is connected to the ignition seat cover 4, and 8 M5 bolt holes 11 are evenly spaced on the upper end face, and the lower end face is connected to the base 17; the base 17 is 8mm thick, 70mm long and wide, and the center hole diameter is 10mm; the main body of the brush seal structure 6 is a cylindrical cavity structure with a closed bottom and an open top, with an inner diameter of 24mm, an outer diameter of 28mm, and a height of 60mm. The diameter of the metal wire of the brush wire bundle 7 is 0.3mm, the outer diameter of the brush seal front plate 8 is 31mm, the inner diameter is 28mm, and the thickness is 2mm. The outer diameter of the brush seal back plate 9 is 34mm, the inner diameter is 28mm, and the thickness is 2mm; the spring 12 is installed on the center guide rod 3 of the ignition device, and the diameter of the spring 12 is 3mm and the pitch is 20mm.

[0043] The specific working mode of a reliable heavy-duty gas turbine ignition device in this embodiment is as follows:

[0044] When the gas turbine is started and ignited, the gas pressure in the pressure chamber 16 is relatively small, and the elastic force of the ignition device spring 12 is much greater than the gas pressure in the pressure chamber 16. The central guide rod 3 of the ignition device moves downward under the elastic force of the spring 12 until the lower end surface of the brush-type sealing structure 6 contacts the upper end surface of the base 17, and the ignition positive electrode 11 and the ignition negative electrode 10 extend into the combustion chamber of the gas turbine. After the ignition command is issued, the ignition cable 18 sends a voltage of up to about 20,000 volts to the ignition positive electrode 11 through the ignition device positive electrode terminal 1. The high voltage breaks through the air between the ignition positive electrode 11 and the ignition negative electrode 10, realizes high-voltage discharge to generate sparks, and ignites the combustible mixture in the combustion chamber. If more than two (including two) flame detectors indicate fire within 60 seconds, the ignition is successful. Then the gas turbine speed continues to increase, the compressor exhaust pressure increases, and the compressor exhaust enters the pressure chamber 16 through the gap between the center hole of the base 17 and the center guide rod 3 of the ignition device. When the gas pressure in the pressure chamber 16 is greater than the elastic force of the spring 12, the center guide rod 3 of the ignition device moves upward under the action of the compressor exhaust pressure until the upper end face of the brush seal structure 6 contacts the lower end face of the ignition seat cover 4, and the ignition positive electrode 11 and the ignition negative electrode 10 exit the gas turbine combustion chamber, and the gas turbine ignition is completed.

[0045] The above shows and describes the basic principle, main features and advantages of the present invention. The brush seal structure used in the embodiment can also be a straight-through labyrinth seal structure or a honeycomb labyrinth seal structure. The present invention is not limited to the above embodiments. The above embodiments and descriptions are only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the invention claimed for protection.

Claims

1. A reliable heavy-duty gas turbine ignition device, characterized in that: It includes an ignition device positive terminal, a ceramic insulator, an ignition device center guide rod, an ignition seat gland, an ignition device cylindrical body, a brush seal structure and a spring; The positive terminal of the ignition device is located in the center of the ignition device, the upper part is connected to the ignition cable, and the lower part is connected to the ignition positive electrode, and is used to conduct high voltage current; The ceramic insulator is located at the periphery of the positive terminal of the ignition device and is arranged coaxially with the positive terminal of the ignition device, and is used to prevent discharge between the positive terminal of the ignition device and the central guide rod of the ignition device; The central guide rod of the ignition device is located outside the ceramic insulator, the lower end of which is connected to the ignition negative electrode and arranged coaxially with the ceramic insulator to drive the ignition positive electrode and the ignition negative electrode to move up and down; The ignition seat pressure cover is located at the uppermost part of the ignition device and is coaxially arranged with the central guide rod of the ignition device; The cylindrical body of the ignition device is a hollow cylindrical cavity, the upper end surface of which is connected to the ignition seat cover, and the lower part is connected to the base; The main body of the brush seal structure is a cylindrical cavity structure with a closed bottom and an open top. A circle of brush bundles is arranged on the periphery of the cylindrical cavity structure and is evenly arranged on the outer wall of the cylindrical cavity. The bottom of the brush seal structure is fixedly sleeved on the central guide rod of the ignition device. The spring is sleeved on the central guide rod of the ignition device on the upper part of the brush seal structure; The lower part of the brush seal structure, the cylindrical cavity and the base form a pressure chamber with a variable size; The brush seal structure can be replaced by a straight-through labyrinth seal structure or a honeycomb labyrinth seal structure.

2. A reliable heavy-duty gas turbine ignition device according to claim 1, characterized in that: The shape of the positive electrode terminal of the ignition device is a cylindrical structure.

3. A reliable heavy-duty gas turbine ignition device according to claim 1, characterized in that: The ceramic insulator is in the shape of a cylindrical structure.

4. A reliable heavy-duty gas turbine ignition device according to claim 1, characterized in that: The ignition seat pressure cover is a cylindrical thin plate structure.

5. A reliable heavy-duty gas turbine ignition device according to claim 1, characterized in that: Cover plate through holes for pressing the ignition seat pressure cover are designed at equal intervals on the ignition seat pressure cover.

6. A reliable heavy-duty gas turbine ignition device according to claim 1, characterized in that: The brush wire bundle is composed of densely arranged thin metal wires, and the material is a high-temperature alloy material.

7. A reliable heavy-duty gas turbine ignition device according to claim 1, characterized in that: The lower part of the brush bundle is a brush-type sealing front plate with an annular thin plate structure, and the upper part is a brush-type sealing back plate with an annular thin plate structure.

8. A reliable heavy-duty gas turbine ignition device according to claim 1, characterized in that: The ignition cathode is an L-shaped narrow thin-strip structure made of high-temperature alloy material, and forms a high-voltage discharge with the ignition cathode located in the center during ignition to ignite the combustible mixed gas in the combustion chamber of the gas turbine.

9. A reliable heavy-duty gas turbine ignition device according to claim 1, characterized in that: During ignition, the gas pressure in the pressure chamber is relatively small. Under the action of the spring, the central guide rod of the ignition device pushes the central guide rod of the ignition device downward, and the ignition positive electrode and the ignition negative electrode extend into the combustion chamber for ignition. After successful ignition, the compressor speed gradually increases, and the compressor exhaust pressure also gradually increases, causing the gas pressure in the pressure chamber to increase. When the gas pressure in the pressure chamber is greater than the spring force, the central guide rod of the ignition device gradually moves upward, and the ignition positive electrode and the ignition negative electrode withdraw from the combustion chamber to prevent them from being burned by high-temperature fuel gas.

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