CN101463764A - High-energy plasma igniter of gas turbine - Google Patents

Abstract

The invention provides a gas turbine high-energy plasma igniter. Including the ignition exciter and the supporting plasma generator; the composition of the ignition exciter includes control relay, transformer isolation circuit, oscillation pulse circuit, arc maintenance module and high-voltage transformer; Insulator, cathode, anode; the present invention can improve the ignition efficiency under a given plasma ignition energy, and at the same time, the electrodes are fully cooled, prolonging the service life of the electrodes. Conversely, due to the improvement of the cooling effect, the plasma ignition energy can be increased, so that inferior fuels such as heavy oil can be ignited under harsher conditions. At the same time, the mounting seat can directly replace the original igniter only by adjusting the position of the screw hole. It can be seen that the present invention has many advantages and is more suitable for practical use.

Description

Gas Turbine High Energy Plasma Igniter

(1) Technical field

The invention relates to a high-energy ignition device in the field of thermal energy and power, in particular to a high-energy plasma igniter suitable for a gas turbine.

(2) Background technology

Nowadays, gas turbines have been widely used and developed in many fields such as aviation, ships, and power generation due to their advantages such as high power, small weight and size, and high efficiency. During the start-up process of a gas turbine, ignition is critical. The success rate of ignition will be directly related to the safe and reliable operation of the whole device.

At present, the commonly used ignition methods include electric spark ignition and semiconductor surface discharge ignition. The electric spark ignition uses the spark discharge or arc discharge between the two electrodes of the combustion chamber to burn the mixture. This method generally has lower ignition energy and longer ignition delay. Semiconductor surface discharge ignition is an ignition device that sandwiches a semiconductor material between the center electrode and the side electrode, and uses the thermal effect of the semiconductor to discharge and start the arc. There is an essential difference between semiconductor discharge and gas arc discharge. Although a larger ignition power can be obtained in this way, due to the lifetime problem of the semiconductor, it directly affects the performance and lifetime of the entire ignition device.

Plasma ignition is a new type of ignition device in recent years, which uses an arc to excite high-temperature plasma to ignite fuel. The advantage is that the success rate of ignition and the stability of combustion can be improved, and the ignition power is large and the reliability is high. But there is a contradictory problem: if the ignition energy is required to be large, the plasma energy will be increased, and then the ablation of the electrode will be aggravated, and the service life will be reduced; however, if the service life of the electrode is to be guaranteed, the ignition energy will be limited.

There have been some public reports on plasma ignition, such as the technical solution disclosed in the utility model patent document named "pulse plasma igniter" with the patent application number 200620020007.0. Practice has proved that there are still many improvements to be made in this technical solution.

(3) Contents of the invention

The purpose of the present invention is to provide a gas turbine high-energy plasma igniter with high ignition efficiency and long service life.

The purpose of the present invention is achieved like this:

Including ignition exciter 1 and matching plasma generator 2; ignition exciter 1 consists of control relay, transformer isolation circuit, oscillation pulse circuit, arc maintenance module and high-voltage transformer; control relay and external 220V AC power supply and control The DC power supply is connected through the aviation connector; the output terminal of the control relay is connected to the input terminal of the transformer isolation circuit; the output terminal of the transformer isolation circuit is connected to the oscillation pulse circuit and the arc maintenance module; the output terminal of the oscillation pulse circuit is connected to a high-voltage transformer; One end is connected to the inner core output of the high-voltage ignition cable, and the other end is connected to the negative pole of the output end of the arc maintenance module; the positive pole of the output end of the arc maintenance module is connected to the casing of the ignition exciter. The composition of the plasma generator 2 includes a mounting base 8, a central axis (3), an insulator 4, a cathode 5, and an anode 7; the mounting base 8 is fastened to the anode 7, and the two form a coaxial ring structure with a cylinder in the middle shaped cavity; on the side of the mounting seat, there is an oil circuit interface, and the oil channel communicates with the oil hole on the cathode 5; Metal material; a ceramic insulator 4 is installed between the mounting seat 8 and the cathode, the central axis 3 and the cathode 5 are connected together, and then loaded into the ceramic insulator 4, and the three remain concentric. The ignition actuator 1 is connected to the plasma generator 2 through a high-voltage ignition cable, and the outer metal shielding layer of the high-voltage ignition cable is connected to the positive electrode of the ignition actuator 1 and the mounting seat of the plasma generator 2; the inner core of the high-voltage ignition cable is connected to the ignition actuator 1. Negative electrode and the inner pole of plasma generator 2. There is a polytetrafluoroethylene insulating layer between the shielding layer and the inner core of the high-voltage ignition cable, and the average thickness of the insulating layer is greater than 2mm.

The present invention may also include:

The cooling of the electrodes of the plasma generator 2 includes fuel cooling and air cooling. The air enters through the cavity between the mounting base 8 and the anode 5, and after cooling the anode 5, it is ejected from the gap between the anode 5 and the cathode 7. The outer surface of 7 also produces a cooling effect; fuel is sprayed from the inside of the cathode 7 to produce a cooling effect on the inside of the cathode 7 .

According to the problems existing in the prior art, the present invention designs the plasma igniter by organically combining plasma ignition with a micro-oil small oil gun. The invention has been designed and improved many times, and through many tests, it has been proved that it is feasible and has practical value.

The invention can improve the ignition efficiency under the given plasma ignition energy, and at the same time, the electrodes are fully cooled, prolonging the service life of the electrodes. Conversely, due to the improvement of the cooling effect, the plasma ignition energy can be increased, so that inferior fuels such as heavy oil can be ignited under harsher conditions. At the same time, the mounting base 8 can directly replace the original igniter only by adjusting the position of the screw hole. It can be seen that the present invention has many advantages and is more suitable for practical use.

Compared with the technical solution disclosed in the utility model patent document with the patent application number 200620020007.0 and the name "pulse plasma igniter", the difference between the two is mainly reflected in: firstly, the plasma generator of the original technical solution does not have an oil injection nozzle structure, and the present invention organically combines the plasma generator 2 with the micro-oil small oil gun, and uses the fuel injection nozzle 6 of the small oil gun as the anode 5 of the plasma generator 2. After the ignition actuator 1 stops working, the The generator can still stably produce a small flare to support combustion in the combustion chamber. Secondly, the cooling method is different. Due to the addition of a micro-oil circuit, the present invention adopts a dual cooling method of fuel oil and air for the electrode, which prolongs the service life of the electrode and also has a preheating effect on the fuel. It has a great effect on combustion stability. Therefore, the two are completely different in design concept, working principle and implementation structure.

(4) Description of drawings

Fig. 1 is a schematic diagram of the connection of the gas turbine high-energy plasma igniter of the present invention.

Fig. 2 is a schematic diagram of the internal structure module of the ignition exciter of the gas turbine high-energy plasma igniter of the present invention.

Fig. 3 is a schematic structural diagram of the plasma generator of the gas turbine high-energy plasma igniter of the present invention.

Fig. 4 is a schematic diagram of the ignition actuator circuit of the gas turbine high-energy plasma igniter of the present invention.

(5) Specific implementation methods

The present invention is described in more detail below in conjunction with accompanying drawing example:

Fig. 1 is a schematic diagram of the connection of the gas turbine high-energy plasma igniter of the present invention. The gas turbine high-energy plasma igniter of the present invention mainly includes: an ignition exciter 1, a matching plasma generator 2 and a high-voltage ignition cable. The number of ignition sources can be determined according to factors such as gas turbine power and fuel. The number of ignition sources is the number of plasma generators 2 . According to the number of 2 plasma generators, the ignition exciter 1 module can be expanded. For example, if one ignition exciter 1 is designed with 2 outputs, if 4 ignition sources are required, two ignition exciters 1 and 4 sets of plasma generators are equipped. 2 and high voltage ignition cable.

Fig. 2 is a schematic diagram of the internal structure module of the ignition exciter 1 of the gas turbine high-energy plasma igniter of the present invention. The ignition exciter 1 is composed of modules, and can freely select single output or dual output, and dual output is used in this embodiment. The control relay can select the appropriate control relay to control the on-off of the 220V AC input according to the size of the control signal.

The main function of the transformer isolation circuit is to isolate the working circuit from the 220V power grid, which not only avoids the interference of the power grid clutter on the working circuit, but also prevents the working circuit from affecting the power grid once an unexpected failure occurs. At the same time, the isolation transformer also increases the 220V AC voltage to increase the output energy of the igniter. The output voltage of the transformer used in this embodiment is 400V/50Hz AC.

The oscillation pulse circuit includes an oscillation module and a high-voltage resonance module. The oscillating module can use silicon controlled rectifiers or MOSFET tubes as switching tubes, triodes can be used to generate oscillating pulses, and special pulse generating chips can also be used. The high-voltage resonance module and the oscillation module work in parallel, and the two ends of the switch tube are connected to the high-voltage resonance module. When the switch tube is turned on, the high-voltage resonance module resonates to generate high-voltage output.

Please refer to FIG. 3 , which is a schematic structural diagram of the plasma generator 2 of the gas turbine high-energy plasma igniter of the present invention. The central axis 3 connects the inner pole of the high-voltage ignition cable and the cathode 5 . An oil supply channel is opened in the middle of the mounting base 8, through which the external oil delivery pipeline transports a small amount of fuel to the fuel injector 6 through the opening connected to the fuel injector 6 on the cathode 5 for atomization and spraying. The cathode 5 is composed of a fuel injector 6 and a protective material inlaid on the surface of its end. The protective material can be high-temperature-resistant and ablation-resistant alloy materials such as zirconium and hafnium to prolong the service life of the cathode 5 . Between the central shaft 3, the cathode 5 and the mounting seat 8, a high temperature resistant insulator 4 is filled to ensure the insulation effect, and ceramic materials can be selected. Between the mounting base 8 and the anode 7, a double-pipe nesting method is adopted, and the compressed air is passed through the annular passage between the two, and then sprayed out from between the anode 7 and the cathode 5 to cool the electrodes. The working mode of the plasma generator 2 is that the ignition exciter 1 generates a high-energy arc between the anode 7 and the cathode 5, and the compressed air is ionized to excite a high-temperature plasma when the compressed air is ejected from the two, and the plasma is pushed to the jet by the air. In front of the oil nozzle 6, the mist fuel and air mixture sprayed out by the oil nozzle 6 is ignited by the high temperature plasma to form a small oil gun. After the thermal equipment is successfully started, the ignition actuator stops working, and the plasma generator can continue to supply micro oil to maintain the combustion of the small oil gun to support the combustion of the main combustion chamber.

Claims (5)

1, a kind of high-energy plasma igniter of gas turbine comprises ignition exciter unit (1) and supporting plasma generator (2); It is characterized in that: the formation of ignition exciter unit (1) comprises control relay, transformation buffer circuit, oscillating impulse circuit, arc maintenance afterflow module and high-tension transformer; Control relay links to each other by Aviation Connector with control direct current supply with outside 220V Alternating Current Power Supply; The control relay output terminal is connected with transformation buffer circuit input end; Transformation buffer circuit output terminal connects oscillating impulse circuit and arc maintenance afterflow module; The oscillating impulse circuit output end connects high-tension transformer; The inner core output of one termination high-voltage ignition cable of high-tension transformer output terminal, the other end connects the negative pole of arc maintenance afterflow module output terminal; The positive contact fire actuator casing of arc maintenance afterflow module output terminal; The formation of plasma generator (2) comprises fitting seat (8), axis (3), insulator (4), negative electrode (5), anode (7); Fitting seat (8) is and the fastening installation of anode (7), and the two becomes coaxial ring structure, and there is cylindrical cavity the centre; Offer the oil circuit interface in the fitting seat side, asphalt channel communicates with oilhole on the negative electrode (5); The head of negative electrode (5) becomes sharp cone distal, and the tip offers nozzle opening; Ceramics insulator (4) is housed between fitting seat (8) and negative electrode, and axis (3) is connected together with negative electrode (5), reinstalls in the ceramics insulator (4); Ignition exciter unit (1) is connected with plasma generator (2) by high-voltage ignition cable, and the external metallization screen layer of high-voltage ignition cable connects the positive pole and plasma generator (2) fitting seat of ignition exciter unit (1); The inner core of high-voltage ignition cable connects the negative pole of ignition exciter unit (1) and the interior utmost point of plasma generator (2).

2, high-energy plasma igniter of gas turbine according to claim 1, it is characterized in that: the cooling of plasma generator (2) electrode comprises fuel cools and air cooling, air is entered by the cavity between fitting seat (8) and the anode (5), and antianode (5) cooling back is sprayed by the gap between anode (5) and the negative electrode (7); Fuel oil is by the inner ejection of negative electrode (7).

3, high-energy plasma igniter of gas turbine according to claim 1 and 2 is characterized in that: the teflon insulation layer is arranged between the screen layer of high-voltage ignition cable and inner core, and the isolation layer average thickness is greater than 2mm.

4, high-energy plasma igniter of gas turbine according to claim 1 and 2 is characterized in that: the pointed cone of the head of negative electrode (5) is inlaid with the zirconium metallic material.

5, high-energy plasma igniter of gas turbine according to claim 3 is characterized in that: the pointed cone of the head of negative electrode (5) is inlaid with the zirconium metallic material.

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