Oscillation suppression member for combustor, combustor, and combustion oscillation suppression method

Abstract

The invention provides an oscillation suppression component for a combustor, the combustor and a combustion oscillation suppression method, and relates to the technical field of combustors, the combustor is provided with a combustion chamber for premixed gas combustion, the oscillation suppression component comprises a body part and a driving part, and the driving part is installed at the outlet end of the combustion chamber. The body part and the combustion chamber are coaxially arranged, the body part is suitable for entering or exiting the combustion chamber through the outlet end in the vertical direction under driving of the driving part, the flow area of an annular outlet defined by the outlet end and the body part is adjusted, the acoustic reflection coefficient at the outlet end is reduced, and therefore combustion oscillation is restrained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of combustor, more particularly, to an oscillation suppression member for a combustor, a combustor and a combustion oscillation suppression method. BACKGROUND

[0002] As a key device for converting chemical energy into thermal energy, combustor is widely used in power generation, heating, industrial manufacturing, aerospace propulsion and other fields. Traditional combustor is usually composed of fuel supply system, air supply system, ignition device and combustion chamber, etc. The core design goal is to achieve efficient and stable mixing and combustion of fuel and oxidant to ensure high combustion efficiency, low pollutant emission and stable operation condition. With the increasing requirements of energy and environment, modern combustor technology has developed from simple diffusion combustion to various advanced combustion modes including premixed combustion, partially premixed combustion, micro-mixed combustion, etc. Innovative technologies such as swirl stabilization, bluff body flame stabilization and catalytic combustion are introduced to expand the extinction limit and reduce emissions of nitrogen oxides, carbon monoxide and unburned hydrocarbons. To further improve performance, the design of combustor is becoming more sophisticated, involving complex fluid mechanics, chemical reaction kinetics and multi-physical field coupling problems. The structure also shows a trend from single function to integration, low inertia and flexible adjustment to adapt to changing workloads and fuel types.

[0003] Combustion oscillation, also known as thermoacoustic instability, is a self-excited oscillation caused by harmful coupling between combustion system and acoustic field. Its physical nature can be described as follows: the flame heat release rate fluctuation in the combustion chamber and the inherent acoustic mode of the combustion system form a positive feedback loop. Specifically, when the combustion process produces heat release rate disturbance, it will exert pressure fluctuation on the combustion chamber like a sound source. These pressure waves are reflected and superimposed at the geometric boundary of the combustion chamber, forming an acoustic field of standing wave or traveling wave mode. This acoustic field affects the heat release rate fluctuation at the next moment by modulating the mixing rate, inflow rate or flame surface area of fuel / oxidant. If the heat release rate fluctuation and pressure fluctuation are in the same phase, the acoustic energy will be continuously supplemented, leading to the amplification of limited amplitude oscillation, resulting in strong pressure pulsation.

[0004] In the related art, methods for suppressing thermoacoustic instability are mainly divided into passive suppression and active suppression. Active control is to use a special monitor and an active actuator, and according to the monitored pressure pulsation in the combustion system and other signals, an appropriate external excitation is actively applied to suppress or eliminate the coupling between the heat release rate pulsation and the pressure oscillation. However, this method requires an additional control system and an execution device, and the control algorithm is also very high, which increases the additional cost, and it is challenging to implement in the extreme conditions of high temperature, high pressure, and high turbulence intensity of the actual gas turbine. Passive control refers to adding some fixed devices in the combustion system to suppress or eliminate combustion oscillation. Common structures include quarter wavelength tubes, Helmholtz resonators, and anti-vibration rings, but these structures are often large in size, high in complexity, and only effective for specific frequencies, requiring a large amount of experiments and debugging in advance. Therefore, how to provide a combustion oscillation suppression structure that can achieve good combustion oscillation suppression effect and has a wide range of applications, reducing the workload of the experiment and debugging process, has become a technical problem to be solved. SUMMARY

[0005] Therefore, the present application provides an oscillation suppression member for a combustor, which can reduce the acoustic reflection coefficient at the outlet end of the combustion chamber, cut off the positive feedback loop, and achieve good suppression effect.

[0006] In order to achieve the above-mentioned purpose, the present application provides an oscillation suppression member for a combustor, the combustor having a combustion chamber for premixed gas combustion, wherein the oscillation suppression member comprises: a driving portion installed at the outlet end of the combustion chamber; a body portion coaxially arranged with the combustion chamber and adapted to enter or exit the combustion chamber along the vertical direction through the outlet end under the driving of the driving portion, and adjust the flow area of the annular outlet defined by the outlet end and the body portion to reduce the acoustic reflection coefficient at the outlet end, thereby suppressing combustion oscillation.

[0007] According to an embodiment of the present application, one end of the body portion serves as a mounting end connected to the driving portion, the cross section of the body portion in the horizontal direction is circular, and the area of the circular cross section gradually decreases from the mounting end to the other end.

[0008] According to an embodiment of the present application, the flow area of the annular outlet defined by the outlet end and the body portion is A r , and satisfies the following formula:

[0009] A r =M a ξ eq A e ;

[0010] wherein M a is the Mach number of the outlet end of the combustion chamber, and ξeq is a pressure loss coefficient of the combustion chamber e is a cross-sectional area of an outlet end of the combustion chamber.

[0011] According to an embodiment of the present invention, a Mach number M of the outlet end of the combustion chamber a is calculated by the following equation:

[0012] ;

[0013] wherein, is a mass flow rate of the premixed gas, p e is a gas flow density at the outlet end of the combustion chamber, g is a specific heat ratio of the gas at the outlet end of the combustion chamber, R gas is a gas constant of the gas at the outlet end of the combustion chamber, T e is a temperature at the outlet end of the combustion chamber.

[0014] According to an embodiment of the present invention, a pressure loss coefficient ξ of the combustion chamber eq is calculated by the following equation:

[0015] ;

[0016] wherein, P e is a total pressure at the outlet end of the combustion chamber, P i is a total pressure at the inlet end of the combustion chamber, p i is a gas flow density at the inlet end of the combustion chamber, v i is an average velocity at the inlet end of the combustion chamber.

[0017] According to an embodiment of the present invention, a cross-sectional area A of the outlet end e is calculated by the following equation:

[0018] ;

[0019] wherein, D e is a diameter of the outlet end of the combustion chamber.

[0020] According to an embodiment of the present invention, the driving portion includes a mounting rod extending in a horizontal direction and positioned above the outlet end, the body portion being mounted to a middle portion of the mounting rod, two extension rods respectively positioned at both ends of the mounting rod, one end of the extension rod being connected to the mounting rod and the other end being connected to an outer wall of the combustion chamber, the extension rod being configured to be elongated or shortened in a vertical direction to move the body portion through the mounting rod.

[0021] The application also provides a burner, comprising: a combustion chamber adapted to burn premixed gas; a premix pipe connected to the inlet end of the combustion chamber and adapted to supply premixed gas to the combustion chamber; and the oscillation suppression member for the burner according to any one of the embodiments described above, which is installed on the outer wall of the outlet end of the combustion chamber.

[0022] According to the embodiment of the application, the first information acquisition module is arranged at the inlet end of the combustion chamber and adapted to acquire total pressure, static pressure and temperature signals at the inlet; the second information acquisition module is arranged at the outlet end of the combustion chamber and adapted to acquire total pressure, static pressure and temperature signals at the outlet; and the third information acquisition module is adapted to acquire pressure pulsation signals generated by the flame in the combustion chamber and obtain the pulsation dominant frequency of the flame when combustion oscillation occurs and the oscillation amplitude corresponding to the pulsation dominant frequency.

[0023] The application also provides a combustion oscillation suppression method, comprising: supplying premixed gas to the combustion chamber and igniting; adjusting the mass flow rate of the premixed gas to cause combustion oscillation in the combustion chamber and record the pulsation dominant frequency f of the flame and the mass flow rate of the premixed gas when the combustion oscillation occurs; calculating the target flow area A r according to formula A a = M eq f e ; calculating the cross-sectional area A r of the body portion of the oscillation suppression member at the outlet end according to formula ; and adjusting the mass flow rate of the premixed gas to cause the combustion chamber to be in a non-oscillation state. c .

[0024] The oscillation suppression member for the burner provided by the application drives the body portion from the outlet end into the combustion chamber through the driving portion, so that the body portion at least partially overlaps with the end face of the outlet end, and the overlapping portion is increased or decreased through reciprocating movement in the vertical direction, the size of the non-overlapping portion is changed, the flow area is adjusted, the acoustic reflection coefficient at the outlet end is reduced to approach 0, the sound-eliminating terminal state is achieved, the positive feedback loop between the flame heat release rate and the sound pressure of the combustion chamber is cut off, the phase of the sound wave and the heat release rate pulsation of the flame is not matched, and then the high-amplitude thermoacoustic limit cycle is suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of the working principle of the oscillation suppression member for the burner and the burner provided by the exemplary embodiment of the application;

[0026] Figure 2 is a perspective structural view of the oscillation suppression member provided by the exemplary embodiment of the application;

[0027] Figure 3 is a flow chart of the combustion oscillation suppression method provided by the exemplary embodiment of the application;

[0028] Figure 4 This is a flame pulsation spectrum diagram of Experiment 1 provided by an exemplary embodiment of the present invention;

[0029] Figure 5 This is a comparison diagram of the average structure of the premixed methane / air flame before and after the main body enters the combustion chamber;

[0030] Figure 6 This is a flame pulsation spectrum diagram of Experiment 2 provided by an exemplary embodiment of the present invention;

[0031] Figure 7 This is a comparison diagram of the average structure of the premixed hydrogen / air flame before and after the main body enters the combustion chamber.

[0032] In the accompanying drawings, the meanings of the reference numerals are as follows:

[0033] 1. Oscillation suppression component;

[0034] 11. Body part;

[0035] 12. Drive unit;

[0036] 121. Mounting rod;

[0037] 122. Telescopic pole;

[0038] 2. Premixed pipe;

[0039] 21. Connecting rod;

[0040] 22. Blunt body;

[0041] 3. Combustion chamber;

[0042] 31. Export end;

[0043] 32. Import end;

[0044] 4. Combustion chamber head;

[0045] 41. Hydrocyclone;

[0046] 5. First information collection module;

[0047] 51. First static pressure sensor;

[0048] 52. First total pressure sensor;

[0049] 53. First thermocouple;

[0050] 6. Second information collection module;

[0051] 61. Second static pressure sensor;

[0052] 62. Second total pressure sensor;

[0053] 63. a second thermocouple;

[0054] 7. a third information collection module;

[0055] 71. a pressure sensor;

[0056] 72. a data processor. DETAILED DESCRIPTION

[0057] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. It is to be understood, however, that these descriptions are merely exemplary and are intended to illustrate the scope of the present application, not to limit it. In the following detailed description of the embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to one skilled in the art that the embodiments of the present application can be practiced without these specific details. In other instances, well-known structures and functions have not been described in detail in order to avoid obscuring aspects of the present application.

[0058] The terms used herein are merely used to describe specific embodiments, and are not intended to limit the present application. The terms "include" and "have" and the like used herein indicate the presence of the described features, steps, operations, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.

[0059] All terms used herein, including technical and scientific terms, have the same meanings as those generally understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having meanings consistent with the context of the present specification, and should not be interpreted in an idealized or excessively formal manner.

[0060] In the case of using expressions similar to "at least one of A, B, and C, etc.", it is generally construed that the expression should be interpreted to have the same meaning as the expression "one or more of the items listed before the conjunction 'and' that precedes the conjunctive term such as 'at least one of,' 'one or more of,' or 'and / or'" (e.g., the expression "at least one of A, B, and C" should be construed to mean A alone, B alone, C alone, A and B together, A and C together, B and C together, or A and B and C together). If the term "or" is used to associate, apply or describe a variety of aspects, properties, states, events, phenomena, etc., it is to be understood that the term "or" is not to be construed in an exclusive sense.

[0061] Figure 1 is a schematic diagram of the operation of an oscillation suppression member for a burner and a burner according to an exemplary embodiment of the present application, Figure 2 is a perspective view of an oscillation suppression member according to an exemplary embodiment of the present application.

[0062] An exemplary embodiment of the present application provides an oscillation suppression member for a burner, as Figures 1-2As shown, the burner has a combustion chamber 3 for premixed gas combustion. The oscillation suppression member 1 includes a body portion 11 and a drive portion 12, wherein the drive portion 12 is mounted at the outlet end 31 of the combustion chamber 3. The body portion 11 is coaxially arranged with the combustion chamber 3 and is adapted to enter or exit the combustion chamber 3 vertically through the outlet end 31 under the drive of the drive portion 12, adjusting the flow area of ​​the annular outlet defined by the outlet end 31 and the body portion 11 to reduce the acoustic reflection coefficient at the outlet end 31, thereby suppressing combustion oscillations.

[0063] In this implementation, the combustion chamber 3 is a commonly used structure in the burner field. The premixed gas is burned in the combustion chamber 3, which is generally a hollow cylindrical structure. The main body 11 is coaxially arranged with the combustion chamber 3 and suspended above the outlet end 31 by the drive unit 12. When the main body 11 does not touch the end face of the outlet end 31, combustion oscillation is more likely to occur. The drive unit 12 drives the main body 11 from the outlet end 31 into the combustion chamber 3, that is, the end face of the main body 11 at least partially overlaps with the end face of the outlet end 31. By reciprocating in the vertical direction, the overlapping part is increased or decreased, and the size of the non-overlapping part, that is, the annular area, is changed, and the flow area is adjusted, thereby reducing the acoustic reflection coefficient at the outlet end 31 to approach 0, realizing the silencing terminal state, cutting off the positive feedback loop between the flame heat release rate and the combustion chamber sound pressure, suppressing combustion oscillation without affecting the average flame shape.

[0064] It should be noted that the positional descriptions such as "above" and "vertical direction" in the above embodiments and the following embodiments are all based on Figures 1-2 The relative positional relationships shown are described, for example, in Figures 1-2 In this configuration, the combustion chamber 3 extends vertically, and the main body 11 is located above the combustion chamber 3 and can reciprocate vertically relative to the combustion chamber 3. The premixed gas flows vertically upwards from below the combustion chamber 3 and enters the combustion chamber 3. In practical applications, if the combustion chamber 3 extends horizontally, the main body 11 is arranged sequentially with the combustion chamber 3 in the same horizontal direction.

[0065] In one exemplary embodiment, such as Figure 2 As shown, one end of the body part 11 is used as a mounting end and is connected to the drive part 12. The cross-section of the body part 11 in the horizontal direction is constructed as a circle, and the area of ​​the circular cross-section gradually decreases from the mounting end to the other end.

[0066] In this embodiment, the main body 11 is a tapered structure with a circular cross-section. The end with the larger diameter is the mounting end. When the main body 11 moves toward the combustion chamber 3, the end with the smaller diameter first passes through the end face of the outlet end 31 and enters the combustion chamber 3. As the main body 11 continues to move, the flow area of ​​the annular outlet gradually decreases, which facilitates adjustment by the operator.

[0067] More specifically, the body portion 11 is preferably a conical body or a circular truncated cone structure. In some other embodiments, the body portion 11 can also be a composite structure formed by butt jointing two identical circular truncated cones at their small diameter ends.

[0068] In an exemplary embodiment, the cross-sectional area of the annular outlet defined by the outlet end 31 and the body portion 11 is A r , and satisfies the formula:

[0069] A r = M a ξ eq A e ;

[0070] where M a is the Mach number of the outlet end 31 of the combustion chamber 3, ξ eq is the pressure loss coefficient of the combustion chamber 3, and A e is the cross-sectional area of the outlet end 31 of the combustion chamber 3.

[0071] In such an embodiment, the result calculated by the above formula is the target cross-sectional area, which is calculated according to the parameter information collected when the combustion oscillation occurs in the combustion chamber 3.

[0072] According to an embodiment of the present disclosure, the Mach number M a of the outlet end 31 of the combustion chamber 3 is calculated by the following formula:

[0073] ;

[0074] where is the mass flow rate of the premixed gas, ρ e is the air flow density of the outlet end 31 of the combustion chamber 3, γ is the specific heat ratio of the outlet end 31 of the combustion chamber 3, R gas is the gas constant of the outlet end 31 of the combustion chamber 3, and T e is the temperature of the outlet end 31 of the combustion chamber 3.

[0075] In such an embodiment, the air flow density ρ e is further calculated by the formula , where P ej is the static pressure of the outlet end 31 of the combustion chamber 3.

[0076] Further according to an embodiment of the present disclosure, the pressure loss coefficient ξ eq of the combustion chamber 3 is calculated by the following formula:

[0077] ;

[0078] where P eP is the total pressure at the outlet end 31 of combustion chamber 3. i The total pressure at the inlet 32 ​​of combustion chamber 3, ρ i v is the airflow density at the inlet 32 ​​of combustion chamber 3. i The average velocity at the inlet end 32 of combustion chamber 3.

[0079] In this implementation, the airflow density ρ at the inlet end 32 i Further through formula The calculation shows that, among them, P ij For the static pressure at the inlet end 32 of combustion chamber 3, T i The temperature at the inlet end 32 of combustion chamber 3 is 32°C.

[0080] More specifically, the cross-sectional area A of the outlet end 31 e Calculated using the following formula:

[0081] ;

[0082] Among them, D e The diameter of the outlet end 31 of the combustion chamber 3.

[0083] In this implementation, the cross-sectional area A of the outlet end 31 e It is calculated using the formula for the area of ​​a circle. The target flow area A is then used. r Through formula A c =A e -A r The area A of the overlapping portion of the end faces of the main body 11 and the outlet end 31 is obtained. c Based on similar principles, through The diameter D of the overlapping portion of the end faces of the main body 11 and the outlet end 31 was calculated. c The operator manually operates the drive unit 12 and measures the diameter of the overlapping part until D is satisfied. c .

[0084] In one exemplary embodiment, such as Figure 2 As shown, the drive unit 12 includes a mounting rod 121 and two telescopic rods 122. The mounting rod 121 extends horizontally and is located above the outlet end 31. The main body 11 is mounted on the middle of the mounting rod 121. The two telescopic rods 122 are located at both ends of the mounting rod 121. One end of the telescopic rod 122 is connected to the mounting rod 121, and the other end is connected to the outer wall of the combustion chamber 3. The telescopic rods 122 are configured to extend or retract vertically to drive the main body 11 to move via the mounting rod 121.

[0085] In such an embodiment, the mounting rod 121 is located above the outlet end 31 with a preset distance between the mounting rod 121 and the outlet end 31, and the mounting rod 121 can drive the body part 11 to reciprocate along the vertical direction under the traction of the two telescopic rods 122, and the preset distance can allow the body part 11 to completely exit the combustion chamber 3 or enter the combustion chamber 3 until the flow area of the annular outlet reaches the minimum value.

[0086] In some other embodiments, the telescopic rod 122 includes but is not limited to a pneumatic cylinder or an electric push rod. As mentioned in the foregoing embodiments, the operator can manually control the pneumatic cylinder or the electric push rod to adjust the position of the body part 11 and measure the diameter of the cross section of the body part 11 at the end face of the outlet end 31 until the calculation result D c is met. In addition, the pneumatic cylinder or the electric push rod can also be controlled by a program, for example, the reference length, the length change amount and the length after the change of the telescopic rod 122 and the diameter D c or the cross-sectional area A c corresponding to the length after the change are input in advance in the program, so as to realize automatic control. The operator only needs to select the D c or A c value equal to or closest to the calculation result, so as to control the telescopic rod 122 to automatically extend or shorten.

[0087] The exemplary embodiments of the present application also provide a burner, as shown in Figures 1-2 , which comprises a combustion chamber 3, a premix pipe 2 and the oscillation suppression member 1 for the burner in any of the above embodiments, wherein the combustion chamber 3 is suitable for burning premixed gas. The premix pipe 2 is connected to the inlet end 32 of the combustion chamber 3 and is suitable for introducing premixed gas into the combustion chamber 3. The oscillation suppression member 1 is installed on the outer wall of the outlet end 31 of the combustion chamber 3.

[0088] In such an embodiment, by using the oscillation suppression member 1 to adjust the flow area of the annular outlet of the outlet end 31 of the combustion chamber 3, the acoustic boundary conditions of the combustion chamber 3 can be smoothly adjusted to change from strong reflection to no reflection in a wide frequency range. The acoustic reflection coefficient at the outlet end 31 tends to be 0, which blocks the acoustic energy feedback loop, so that the phase of the acoustic wave and the flame heat release rate pulsation is not matched, thereby suppressing the high-amplitude thermoacoustic limit cycle. Moreover, the wide-frequency sound-absorbing characteristics help to maintain the thermoacoustic stability state under wide operating conditions, effectively realizing the control of thermoacoustic instability.

[0089] According to the embodiments of the present application, the combustion chamber head 4 is arranged between the combustion chamber 3 and the premix pipe 2, and the connecting rod 21 is installed in the premix pipe 2 along the axis of the premix pipe 2. The end of the connecting rod 21 close to the combustion chamber 3 is provided with the bluff body 22, which is configured to gradually expand along the flow direction of the premixed gas to stabilize the combustion flame.

[0090] A swirler 41 is arranged at the junction of the combustion chamber head 4 and the premix pipe 2, and is sleeved on the connecting rod 21, and is adapted to improve the uniformity of the premix gas, so as to stabilize the combustion flame.

[0091] Preferably, the swirl number of the swirler 41 ranges from 0.1 to 0.3.

[0092] In an exemplary embodiment, as shown in Figure 1 The burner further comprises a first information acquisition module 5, a second information acquisition module 6 and a third information acquisition module 7. The first information acquisition module 5 is arranged at the outlet end 31 of the combustion chamber 3, and is adapted to acquire the total pressure, static pressure and temperature signals at the outlet. The second information acquisition module 6 is arranged at the inlet end 32 of the combustion chamber 3, and is adapted to acquire the total pressure, static pressure and temperature signals at the inlet. The third information acquisition module 7 is adapted to acquire the pressure pulsation signals generated by the flame in the combustion chamber 3, and to obtain the pulsation main frequency of the flame when combustion oscillation occurs and the oscillation amplitude corresponding to the pulsation main frequency.

[0093] In such an embodiment, the first information acquisition module 5 and the second information acquisition module 6 are similar in structure, and each comprises a total pressure, total temperature and static pressure compound probe arranged at the outlet end 31 / inlet end 32, and a sensor connected to the compound probe, such as a first static pressure sensor 51, a first total pressure sensor 52 and a first thermocouple 53, a second static pressure sensor 61, a second total pressure sensor 62 and a second thermocouple 63. The third acquisition module 7 comprises a pressure sensor and a data processor. The pressure sensor is arranged on the inner wall of the combustion chamber 3, and is adapted to monitor the pressure pulsation signals generated by the flame in the combustion chamber 3 in real time and at a fast dynamic state, and to acquire pressure data through the connected data processor, so as to display the dynamic pressure spectrum of the combustion chamber 3 in real time. When combustion oscillation occurs in the combustion chamber 3 (for example, obvious abnormal sound or obvious change in the spectrum with a peak value), the pulsation main frequency at this time and the oscillation amplitude corresponding to the pulsation main frequency are recorded, so as to be used as a control for experiments.

[0094] Figure 3 is a flow chart of the combustion oscillation suppression method provided by the exemplary embodiment of the present application.

[0095] The exemplary embodiment of the present application further provides a combustion oscillation suppression method, which is applied to the burner in any of the above-mentioned embodiments, and comprises steps S1-S4, as shown in Figure 3 .

[0096] Step S1, introducing premix gas into the combustion chamber 3 and igniting.

[0097] Step S2, adjusting the mass flow rate of the premix gas, so that the combustion chamber 3 generates combustion oscillation and the pulsation main frequency f of the flame at this time and the mass flow rate of the premix gas .

[0098] Step S3: According to formula A r =M a ξ eq A e Calculate the target circulation area A r ;

[0099] Step S4: According to formula A c =A e -A r Calculate the cross-sectional area A of the body portion 11 of the oscillation suppression component 1 at the outlet end 31. c .

[0100] In this implementation, the burner is not equipped with the oscillation suppression component 1 in steps S1 to S4.

[0101] Figure 4 This is a flame pulsation spectrum diagram of Experiment 1 provided by an exemplary embodiment of the present invention. Figure 5 This is a comparison diagram of the average structure of the premixed methane / air flame before and after the main body enters the combustion chamber. Figure 6 This is a flame pulsation spectrum diagram of Experiment 2 provided by an exemplary embodiment of the present invention. Figure 7 This is a comparison diagram of the average structure of the premixed hydrogen / air flame before and after the main body enters the combustion chamber.

[0102] The following control experiments further illustrate the technical effects of the present invention.

[0103] Experiment 1: Methane / air premixed gas was introduced into combustion chamber 3 with a diameter of 130 mm (radius of 0.065 m) and ignited. The mass flow rate of methane / air premixed gas 16 was adjusted to induce combustion oscillation within combustion chamber 3. The dominant frequency f of the flame oscillation, the corresponding oscillation amplitude P′, and the mass flow rate of the methane / air premixed gas were recorded by the third information acquisition module 7. In this experiment, the mass flow rate of the methane / air premixed gas was... The velocity is 0.028 kg / s. At this time, the vibration suppression component 1 is not installed at the outlet end 31 of the combustion chamber 3, and the flame undergoes thermoacoustic vibration with a dominant frequency f = 453 Hz and a corresponding amplitude of P′ = 1021 Pa. According to formula A... r =M a ξ eq A e , , , , , , Perform the calculation, where P ej =101305.7 Pa, T e =1620K, Pij = 101325 Pa, T i = 300 K, P i = 101326.9 Pa, P e = 101318.5 Pa, γ = 1.3, R gas = 297.1 J / (kg-K), R gasi = 297.1 J / (kg-K). A r = 0.00309 m 2 = 3090 mm 2 , further calculation can get D c = 0.1138 m = 113.8 mm. Adjust the position of the body part 11 so that its diameter at the end face of the outlet end 31 of the combustion chamber 3 is as close as possible or equal to 113.8 mm. At this time, the third information acquisition module 7 records the main frequency f = 403 Hz of the flame oscillation and the corresponding oscillation amplitude P' = 73 Pa. It should be noted that the specific heat ratio γ of the gas at the outlet end 31 of the combustion chamber 3, the gas constant R gas at the outlet end 31 of the combustion chamber 3 and the gas constant R gasi at the inlet end 32 of the combustion chamber 3 are calculated according to the average molecular weight of the combustion products and the high-temperature thermodynamic properties.

[0104] As shown in Figure 4 , when the outlet end 31 of the combustion chamber 3 is not provided with the oscillation suppression member 1 or the distance between the two is far, the main frequency of the flame pulsation and the corresponding amplitude are f = 453 Hz and P' = 1021 Pa respectively, and at this time the flame oscillates violently. When the body part 11 of the oscillation suppression member 1 enters the combustion chamber 3, and the diameter D c of the cross section of the body part 11 at the end face of the outlet end 31 of the combustion chamber 3 is 60 mm, at this time the main frequency of the flame pulsation and the corresponding amplitude are f = 471 Hz and P' = 1605 Pa respectively, and the flame oscillates violently; when the diameter D c of the cross section of the body part 11 at the end face of the outlet end 31 of the combustion chamber 3 is 25 mm, at this time the main frequency of the flame pulsation and the corresponding amplitude are f = 463 Hz and P' = 1476 Pa respectively, and the flame oscillates violently; when the diameter D c of the cross section of the body part 11 at the end face of the outlet end 31 of the combustion chamber 3 is 80 mm, at this time the main frequency of the flame pulsation and the corresponding amplitude are f = 445 Hz and P' = 596 Pa respectively, and the flame oscillates moderately; when the diameter D cWhen the diameter is 100mm, the dominant frequency and corresponding amplitude of the flame pulsation are f=418Hz and P′=313Pa, respectively, and the flame oscillates to a moderate degree; when the diameter D of the cross-section of the main body 11 at the outlet end 31 of the combustion chamber 3 is... c When the target value is 113.8 mm, the dominant frequency of flame pulsation and the corresponding amplitude are f = 403 Hz and P′ = 73 Pa, respectively. The amplitude of flame pulsation is significantly reduced, and thermoacoustic oscillation is suppressed. Compared with when D... c When the flame amplitude is 60 mm, compared to the amplitude P′=1605 Pa, the flame pulsation amplitude is reduced by approximately 95.5%. The 73 Pa amplitude present at this point is likely due to turbulent flame and flame propagation. Therefore, when the flow area of ​​the annular outlet formed by the body 11 and the outlet end 31 of the combustion chamber 3 satisfies this formula A... r =M a ξ eq A e At that time, the thermoacoustic oscillations occurring in combustion chamber 3 can be significantly suppressed.

[0105] Figure 5 This shows that when the main body 11 does not enter the combustion chamber 3 ( Figure 5 (Left) and the main body 11 enter the combustion chamber 3, and the diameter D of the cross-section of the main body 11 at the end face of the outlet end 31 of the combustion chamber 3 is... c When the target value is 113.8 mm ( Figure 5 The average structure of the premixed methane / air flame (right) shows that it has no effect on the average shape of the methane / air flame. Therefore, it is demonstrated that the thermoacoustic instability of the system can be controlled by changing the acoustic reflection coefficient R downstream of the outlet end 31 of the combustion chamber 3 without affecting the flame structure.

[0106] Experiment 2: A hydrogen / air premixed gas was introduced into a combustion chamber 3 with a diameter of 100 mm (radius of 0.05 m) and ignited. The mass flow rate of the hydrogen / air premixed gas was adjusted to induce combustion oscillations within the combustion chamber 3. The flame pulsation amplitude P′ and the mass flow rate of the hydrogen / air premixed gas were recorded at this time. In this experiment, the mass flow rate of the hydrogen / air premixed gas was... The velocity is 0.018 kg / s. At this time, the vibration suppression component 1 is not installed at the outlet end 31 of the combustion chamber 3, and the flame undergoes thermoacoustic vibration, with a dominant frequency f = 576 Hz and a corresponding amplitude of 1490 Pa. According to formula A... r =M a ξ eq A e , , , , , , Perform the calculation, where P ej =101315.1 Pa, T e =1640K, P ij =101325Pa, T i =297K, P i =101327.7 Pa, P e =101315.4 Pa was measured by the first information acquisition module 5 and the second information acquisition module 6. γ=1.312, R gas =316.4 J / (kg·K), R gasi =350.6 J / (kg·K). The calculated value of A is... r ≈0.00200m 2 =2000mm 2 Further calculations yield D c ≈0.0863m=86.3mm. Adjust the position of the main body 11 so that its diameter at the end face of the outlet end 31 of the combustion chamber 3 is as close as possible to or equal to 86.3mm. At this time, the third information acquisition module 7 records the main frequency f=521Hz of the flame oscillation and the corresponding oscillation amplitude P′=55Pa.

[0107] like Figure 6 As shown, when the oscillation suppression component 1 is not installed at the outlet end 31 of the combustion chamber 3 or the distance between them is large, the dominant frequency and corresponding amplitude of the flame pulsation are f=576Hz and P′=1490Pa, respectively, at which time the flame oscillates violently. When the body part 11 of the oscillation suppression component 1 enters the combustion chamber 3, and the diameter D of the cross-section of the body part 11 at the end face of the outlet end 31 of the combustion chamber 3 is... c When the diameter is 40mm, the dominant frequency and corresponding amplitude of the flame pulsation are f=581Hz and P′=1693Pa, respectively, and the flame oscillates violently; when the diameter D of the cross-section of the main body 11 at the outlet end 31 of the combustion chamber 3 is... c When the diameter is 75mm, the dominant frequency and corresponding amplitude of the flame pulsation are f=568Hz and P′=1245Pa, respectively, and the flame oscillates violently; when the diameter D of the cross-section of the main body 11 at the outlet end 31 of the combustion chamber 3 is... c When the diameter is 60mm, the dominant frequency and corresponding amplitude of the flame pulsation are f=553Hz and P′=1121Pa, respectively, and the flame oscillates violently; when the diameter D of the cross-section of the main body 11 at the outlet end 31 of the combustion chamber 3 is... c When the diameter is 20mm, the dominant frequency and corresponding amplitude of the flame pulsation are f=532Hz and P′=653Pa, respectively, and the flame oscillates to a moderate degree; when the diameter D of the cross-section of the main body 11 at the outlet end 31 of the combustion chamber 3 is... cWhen the target value is 86.3 mm, the dominant frequency of flame pulsation and the corresponding amplitude are f = 521 Hz and P′ = 55 Pa, respectively. The amplitude of flame pulsation is significantly reduced, and thermoacoustic oscillation is suppressed. Compared with when D... c Compared to the amplitude P′=1693Pa at 40mm, the flame pulsation amplitude decreased by approximately 96.8%. The 55Pa amplitude present at this point is likely due to turbulent flame and flame propagation. Therefore, when the flow area of ​​the annular outlet formed by the body 11 and the outlet end 31 of the combustion chamber 3 satisfies this formula A... r =M a ξ eq A e At that time, the thermoacoustic oscillations occurring in combustion chamber 3 can be significantly suppressed.

[0108] Figure 7 This shows that when the main body 11 does not enter the combustion chamber 3 ( Figure 5 (Left) and the main body 11 enter the combustion chamber 3, and the diameter D of the cross-section of the main body 11 at the end face of the outlet end 31 of the combustion chamber 3 is... c When the target value is 86.3mm ( Figure 5 The average structure of the premixed hydrogen / air flame (right) shows that it has no effect on the average shape of the hydrogen / air flame. Therefore, it is demonstrated that the thermoacoustic instability of the system can be controlled by changing the acoustic reflection coefficient R downstream of the outlet end 31 of the combustion chamber 3 without affecting the flame structure.

[0109] Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0110] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. An oscillation suppression member for a burner, the burner having a combustion chamber for premixed gas combustion, characterized in that, The oscillation suppression component includes: A drive unit is installed at the outlet end of the combustion chamber; The main body is arranged coaxially with the combustion chamber and is adapted to enter or exit the combustion chamber vertically through the outlet end under the drive of the drive unit. It adjusts the flow area of ​​the annular outlet defined by the outlet end and the main body to reduce the acoustic reflection coefficient at the outlet end, thereby suppressing combustion oscillation.

2. The oscillation suppression component according to claim 1, characterized in that, One end of the main body is used as a mounting end and is connected to the drive unit. The cross-section of the main body in the horizontal direction is constructed as a circle, and the area of ​​the circular cross-section gradually decreases from the mounting end to the other end.

3. The oscillation suppression component according to claim 2, characterized in that, The flow area of ​​the annular outlet defined by the outlet end and the main body is A. r And it satisfies the following formula: A r =M a x eq A e ; Among them, M a ξ is the Mach number at the outlet of the combustion chamber. eq A is the pressure loss coefficient of the combustion chamber. e This is the cross-sectional area of ​​the outlet end of the combustion chamber.

4. The oscillation suppression component according to claim 3, characterized in that, The Mach number M at the outlet of the combustion chamber a Calculated using the following formula: ； in, ρ is the mass flow rate of the premixed gas. e R is the gas flow density at the outlet of the combustion chamber, γ is the specific heat ratio of the combustion gas at the outlet of the combustion chamber, and R is the gas flow density at the outlet of the combustion chamber. gas T is the gas constant at the outlet of the combustion chamber. e The temperature at the outlet end of the combustion chamber.

5. The oscillation suppression component according to claim 4, characterized in that, The pressure loss coefficient ξ of the combustion chamber eq Calculated using the following formula: ； Among them, P e P is the total pressure at the outlet of the combustion chamber. i ρ is the total pressure at the inlet of the combustion chamber. i v is the airflow density at the inlet of the combustion chamber. i The average velocity at the inlet of the combustion chamber is denoted as .

6. The oscillation suppression component according to claim 5, characterized in that, The cross-sectional area A at the outlet end e Calculated using the following formula: ； Among them, D e The diameter of the outlet end of the combustion chamber is denoted as .

7. The oscillation suppression component according to any one of claims 1-6, characterized in that, The drive unit includes: The mounting rod extends horizontally and is located above the outlet end, with the body portion mounted on the middle of the mounting rod; Two telescopic rods are located at both ends of the mounting rod, one end of the telescopic rod is connected to the mounting rod, and the other end is connected to the outer wall of the combustion chamber 3. The telescopic rods are configured to extend or shorten in the vertical direction so as to drive the main body to move through the mounting rod.

8. A burner, characterized in that, include: Combustion chamber, suitable for combustion of premixed gas; A premixing pipe, connected to the inlet end of the combustion chamber, is suitable for introducing premixed gas into the combustion chamber; The oscillation suppression member for a burner as described in any one of claims 1-7 is installed on the outer wall of the outlet end of the combustion chamber.

9. The burner according to claim 8, characterized in that, Also includes: The first information acquisition module is located at the inlet end of the combustion chamber and is suitable for acquiring total pressure, static pressure and temperature signals at the inlet. The second information acquisition module is located at the outlet end of the combustion chamber and is suitable for acquiring total pressure, static pressure and temperature signals at the outlet. The third information acquisition module is suitable for acquiring the pressure pulsation signal generated by the flame in the combustion chamber, and for obtaining the main frequency of the flame pulsation and the oscillation amplitude corresponding to the main frequency of the pulsation when combustion oscillation occurs.

10. A method for suppressing combustion oscillations, characterized in that, Applied to the burner as described in any one of claims 8-9, comprising: Premixed gas is introduced into the combustion chamber and ignited; The mass flow rate of the premixed gas is adjusted to induce combustion oscillations in the combustion chamber, and the dominant frequency f of the flame pulsation and the mass flow rate of the premixed gas are recorded at this time. ; According to formula A r =M a ξ eq A e Calculate the target circulation area A r ; According to the formula Calculate the cross-sectional area A of the body of the oscillation suppression component at the outlet end. c .

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