CN101493229A - Control method for multiple tail tube pulsating combustor and apparatus - Google Patents

Abstract

The invention discloses a control method and device for a multi-tailpipe pulsation burner. By adjusting the opening of the valve in front of the induced draft fan, the internal pressure of the decoupling chamber, that is, the outlet pressure of the tailpipe is changed, and the acoustic characteristics in the pulsation burner are changed to ensure The pulsating combustion and heat release of the tailpipe section, and the connecting pipe section can also be used as a steady-state heating surface for heat exchange. The pulsating burner in the device of the present invention adopts the basic structure of a Helmholtz type pulsating burner, which is composed of a mixing chamber, an air supply device, an ignition device, a combustion chamber, a tailpipe, and a decoupling chamber, and adopts a multi-tailpipe structure. The device for controlling the burner is set behind the decoupling chamber and consists of connecting pipes, valves, exhaust pipes, induced draft fans, and electric motors. The control method of the invention has the advantages of convenient operation, stable work and high efficiency.

Description

A control method and device for a multi-tailpipe pulsation burner

technical field

The invention relates to a control method and device for a multi-tailpipe pulsation burner

Background technique

Pulse combustion is a high-efficiency, energy-saving and low-pollution combustion technology. When the pulsating burner is running, it will emit a loud noise. The pulsating airflow in the combustion chamber is the main noise source. At the same time, the pulsating combustion has a high coupling. When the acoustic conditions of the tail change, it will inevitably affect the operating characteristics of the pulsating burner. Influence. To control combustion noise and random fluctuations in tail acoustic conditions, a decoupling chamber is necessary. The function of the decoupling chamber is to make the airflow flow smoothly and reduce the combustion noise. Because the noise intensity is closely related to turbulence, it changes with the Reynolds number. In addition, another more important function is to keep the tailpipe outlet pressure stable, avoid external pressure changes from affecting the combustion state, and ensure stable combustion pulsation.

In the past, changing the operating characteristics of the pulsating burner mainly focused on changing the geometric dimensions of the various components of the burner, or changing the supply mode of fuel and oxidant, without considering the influence of the pressure of the decoupling chamber. From the point of view of the principle of the pulsating burner, the pressure pulsation amplitude at the outlet plane of the tailpipe should be zero, but in the actual burner, there will be a certain amount of sound energy radiated from here, so the acoustic characteristics of the decoupling chamber will definitely affect the combustion. operating characteristics of the device.

Contents of the invention

In order to facilitate the adjustment of the operating characteristics of the pulsating burner, ensure stable pulsation in the burner, and improve the stability of the overall operation of the burner, the present invention controls the combustion intensity, acoustic pressure amplitude, frequency, etc. by changing the pressure of the decoupling chamber, thereby adjusting Heat exchange strength.

The technical scheme that the present invention takes is:

Set a flow regulating valve behind the decoupling chamber, and connect an induced draft fan at the end of the exhaust pipe. By adjusting the opening of the valve in front of the induced draft fan, the internal pressure of the decoupling chamber, that is, the outlet pressure of the tailpipe, can be changed to change the acoustics in the burner. Features to ensure pulsating combustion of the tailpipe section.

The working process of the pulse burner without control device is as follows:

The preliminarily mixed fuel and air are ignited, and the pressure in the combustion chamber increases with the release of heat. When the pressure in the combustion chamber rises to be higher than the air or fuel supply pressure, the two air intake devices are closed, and the hot gas cannot flow back, but can only flow backward along the tailpipe, expand and discharge, and the pressure in the combustion chamber also drops accordingly. Due to the inertia of the gas column flowing at high speed, when the pressure in the combustion chamber drops below the ambient pressure at the outlet of the tailpipe, the combustion products continue to be discharged, causing a partial vacuum in the combustion chamber to form a negative pressure. When the pressure in the combustion chamber drops below the pressure before the air or gas inlet, the intake device is opened again, and fresh air and fuel enter the combustion chamber again. At the same time, part of the combustion products flow back from the tailpipe to the combustion chamber, followed by the intake of fresh cold air into the tailpipe. The two air streams compress the medium in the combustion chamber, so that the pressure in the combustion chamber rises. The fresh fuel and air are mixed with the hot gas and heated, automatically ignited by the unextinguished fire, start to burn, release heat, and start a new cycle of combustion and exhaust process. This periodic combustion process is self-circulating, and it does not need to be re-ignited, and it can continue to work.

The working process of the above-mentioned pulsating burner is to maintain stable pulsating combustion only when the pulsating state of the gas flow in the burner complies with the Rayleigh criterion. Changes in airflow velocity, heat release rate, air-fuel ratio, and burner structure all affect the characteristics of pulsating combustion, which may cause the burner to run unstable, fail to pulsate, or even fail to operate at all.

The control method of the multi-tailpipe pulsation burner of the present invention is as follows:

The burner adopts the basic structure of the Helmholtz type pulsating burner, that is, the burner is composed of a mixing chamber, an air supply device, an ignition device, a combustion chamber, a tail pipe, and a decoupling chamber, and the tail pipe adopts a multi-tail pipe structure . The device for controlling the burner is set behind the decoupling chamber and consists of connecting pipes, valves, exhaust pipes, induced draft fans, and electric motors. The working process of the pulse burner is as described above.

The induced draft fan is driven by a motor, and the amount of induced air can be controlled by adjusting the opening of the exhaust valve. The greater the induced air volume, the lower the pressure in the decoupling chamber. When the volume of flue gas discharged from the tailpipe to the decoupling chamber is equal to the volume of induced air, the pressure in the decoupling chamber is equal to the ambient pressure, which is equivalent to the exhaust of the tailpipe to the ambient space; When the amount of flue gas discharged from the tailpipe to the decoupling chamber is greater than the amount of induced air, the pressure in the decoupling chamber is higher than the ambient pressure, and the pressure in the combustion chamber also increases accordingly. Enhanced, the difference between the pressure in the combustion chamber and the pressure in the decoupling chamber determines the strength of the pulsation; when the amount of flue gas discharged from the tailpipe to the decoupling chamber is less than the amount of induced air, the pressure in the decoupling chamber is lower than the ambient pressure, and the pressure in the combustion chamber also decreases accordingly , the combustion heat release of combustible gas in the combustion chamber is weakened, and the resistance in the tailpipe is also weakened. The difference between the pressure in the combustion chamber and the pressure in the decoupling chamber determines the strength of the pulsation. In this way, by adjusting the valve to change the pressure in the decoupling chamber to change the acoustic characteristics of the tailpipe outlet, the flue gas pulsation in the tailpipe section can be guaranteed, and at the same time, the pressure in the decoupling chamber can be monitored to control the burner in the optimal or required operating state .

When the burner is running stably, there is always a steady flue gas flow in the connecting pipe between the outlet of the decoupling chamber and the exhaust valve, so the connecting pipe section can be used as a steady-state heating surface for heat exchange.

The atmospheric valve is used to adjust the amount of air mixed into the exhaust pipe, thereby controlling the temperature of the flue gas entering the induced draft fan. It is used in conjunction with the exhaust valve to control and adjust the working pressure head of the induced draft fan. If the pressure and temperature of the flue gas behind the exhaust valve and in front of the induced draft fan are within the working range of the induced draft fan, it is not necessary to set the atmospheric valve.

The advantages of the multi-tailpipe pulsation burner control method of the present invention are as follows:

1. The multi-tail pipe structure is adopted to increase the heat exchange area;

2. Ensure the pulsating combustion and heat exchange of the tailpipe section;

3. The outlet pressure of the tailpipe is easy to adjust and control, the work is stable and the efficiency is high;

4. The connecting pipe section can also perform heat exchange, which is equivalent to the heating surface of a steady-state burner.

Description of drawings

Fig. 1 is the schematic diagram of device of the present invention

Reference signs: 1. Air supply device; 2. Mixing chamber; 3. Ignition device; 4. Combustion chamber; 5. Tail pipe; 6. Decoupling chamber; 7. Connecting pipe; 8. Exhaust valve; 9. Exhaust Trachea; 10. Atmospheric valve; 11. Electric motor; 12. Induced fan.

Detailed ways

As shown in Figure 1, the above-mentioned multi-tail pipe pulsation burner and its control device are composed of an air supply device 1, a mixing chamber 2, an ignition device 3, a combustion chamber 4, a tail pipe 5, a decoupling chamber 6, a connecting pipe 7, an exhaust Air valve 8, exhaust pipe 9, atmosphere valve 10, motor 11, induced draft fan 12 form. The above-mentioned tailpipe 4 adopts a multi-tailpipe structure, and the quantity and size are not limited.

As shown in Figure 1, the working process of the pulse burner is: gas and air enter the mixing chamber 2 through the gas supply device 1, and at the tail of the mixing chamber 2 (the side leading to the combustion chamber 4), the ignition device 3 will mix the gas ignite. Combustion raises the pressure in the combustion chamber 4 with heat release. When the pressure in the combustion chamber 4 rises to be greater than the pressure in the mixing chamber 2, the gas in the mixing chamber 2 cannot flow into the combustion chamber 4. Although the hot gas in the combustion chamber 4 will enter the mixing chamber 5, due to the resistance of the gas supply device Large, the hot gas can only flow backward along the tailpipe 5, expand and discharge, and the pressure in the combustion chamber 4 also drops thereupon. When the pressure in the combustion chamber 4 drops below the pressure at the outlet of the mixing chamber 2, fresh air and gas enter the combustion chamber 4 again. When the pressure of the combustion chamber 4 drops below the outlet pressure of the tailpipe 5, due to the inertia of the gas flowing at high speed, the hot gas will continue to be discharged until the flow rate drops to zero. At this time, part of the combustion products flow back from the tailpipe 5 to the combustion chamber 4, and fresh cold air is sucked into the tailpipe 5. In this way, the supply air flow of fuel and air and the return flow of the tailpipe 5 compress the medium in the combustion chamber 4, so that the pressure in the combustion chamber 4 rises. The mixed fresh fuel and air are heated by the hot gas, automatically ignited by the flame left over from the previous cycle, burn and release heat, and start a new cycle of combustion and exhaust process. This periodic combustion process is self-circulating and can continue without re-ignition.

As shown in Figure 1, the control method of the pulsating burner is as follows: the induced draft fan 12 is driven by the motor 11, and the opening of the exhaust valve 8 is adjusted to control the induced air volume. The greater the induced air volume, the lower the pressure in the decoupling chamber 6. When the amount of flue gas discharged from the tailpipe 5 to the decoupling chamber 6 is equal to the induced air volume, the pressure in the decoupling chamber 6 is equal to the ambient pressure, which is equivalent to that of the tailpipe 5. The smoke in the decoupling chamber 6 is exhausted to the ambient space; when the amount of flue gas discharged from the tailpipe 5 to the decoupling chamber 6 is greater than the induced air volume, the pressure in the decoupling chamber 6 is higher than the ambient pressure, and the pressure in the combustion chamber 4 also increases accordingly, and the combustion The combustion heat release of the combustible gas in the chamber 4 intensifies, and the resistance in the tailpipe 5 also increases. The difference between the pressure in the combustion chamber 4 and the pressure in the decoupling chamber 6 determines the strength of the pulsation; when the tailpipe 5 discharges to the decoupling chamber 6 When the flue gas volume is less than the induced air volume, the pressure in the decoupling chamber 6 is lower than the ambient pressure, and the pressure in the combustion chamber 4 is also reduced accordingly, the combustion heat release of the combustible gas in the combustion chamber 4 is weakened, and the resistance in the tailpipe 5 is also weakened. The difference between the pressure in the combustion chamber 4 and the pressure in the decoupling chamber 6 determines the strength of the pulsation. In this way, by adjusting the exhaust valve 8 to change the pressure in the decoupling chamber 6 and then changing the acoustic characteristics of the outlet of the tailpipe 5, the flue gas pulsation in the 5th section of the tailpipe can be guaranteed, and at the same time, the pressure in the decoupling chamber 6 can be monitored Control at optimal or desired operating state. The atmospheric valve 10 is used to adjust the amount of air mixed into the exhaust pipe 9 , and then control the temperature of the flue gas entering the induced draft fan 12 . It is used in conjunction with the exhaust valve 8 to control and adjust the working pressure head of the induced draft fan 12 . If the pressure and temperature of the flue gas behind the exhaust valve 8 and in front of the induced draft fan 12 are all within the work tolerance range of the induced draft fan 12, then the atmospheric valve 10 may not be provided.

As shown in Figure 1, when the burner is running stably, there is always a steady flow of flue gas in the connecting pipe 7 between the outlet of the decoupling chamber 6 and the exhaust valve 8, so the connecting pipe 7 can be used as a steady-state heating surface for heat exchange.

Claims (5)

1. control method for multiple tail tube pulsating combustor, it is characterized in that: flow control valve is set in the decoupling chamber back, and connect an air-introduced machine at the blast pipe afterbody, changing decoupling chamber's internal pressure by the valve opening before the adjusting air-introduced machine is tail pipe outlet pressure size, change the acoustic characteristic in the burner, guarantee the intermittent combustion heat exchange of tailpipe section.

2. adopt the multiple tail tube pulsating combustor control device of the described method of claim 1, it is characterized in that: pulsating combusting device is made up of feeder (1), mixing chamber (2), igniter (3), combustion chamber (4), tail pipe (5), decoupling chamber (6), above-mentioned tail pipe (4) adopts many tail pipes structure, and quantity, size do not limit; Control device is made up of tube connector (7), air bleeding valve (8), blast pipe (9), atmos-valve (10), motor (11), air-introduced machine (12).

3. multiple tail tube pulsating combustor control device according to claim 2, it is characterized in that: air-introduced machine (12) is driven by motor (11), the aperture of regulating air bleeding valve (8) is with control air inducing amount, change the pressure in the decoupling chamber (6) and then change the acoustic characteristic that tail pipe (5) exports, guarantee the flue gas pulsation of tail pipe (5) section, the pressure of monitoring (6) in the decoupling chamber simultaneously can be controlled at burner best or required running status.

4. multiple tail tube pulsating combustor control device according to claim 2 is characterized in that: atmos-valve (10) is used for regulating the air capacity of sneaking into blast pipe (9), and then controls the flue-gas temperature that enters air-introduced machine (12).It and air bleeding valve (8) are used, and can control to adjust air-introduced machine (12) working head.Behind the event exhaust valve (8), the pressure of the preceding flue gas of air-introduced machine (12), temperature all within air-introduced machine (12) work tolerance range, then can be provided with atmos-valve (10).

5. multiple tail tube pulsating combustor control device according to claim 2, it is characterized in that: during burner stable operation, it is stable flow of flue gas all the time in the tube connector (7) that decoupling chamber (6) exports between the air bleeding valve (8), so tube connector (7) can be used as the stable state heating surface and carries out heat exchange.

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