Gas flow pulsation generating device

Abstract

The invention relates to the technical field of combustion chambers, and provides a gas flow pulsation generating device which comprises a generator body, a moving part and a driving mechanism. A first through hole is formed in the end face of one end of the generator body, the generator body is provided with a first cavity, and the first cavity communicates with the first through hole; the first end of the moving part is located in the first through hole, the first end of the moving part is of a cone structure, the moving part can reciprocate along the first through hole under the action of the driving mechanism, and high-temperature fuel gas generated by the combustion chamber enters the first cavity through a gap between the cone structure and the first through hole. According to the gas flow pulsation generating device, the driving mechanism drives the moving part to do reciprocating rectilinear motion along the first through hole so as to change the actual gas inlet area of the first through hole, so that corresponding flow pulsation is generated at the inlet of the combustion chamber, and the gas flow pulsation generating device can not only cope with a large-flow working condition, but also can also cope with a large-flow working condition. The structure is simple, and the manufacturing cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of combustion chambers, and in particular to a gas flow pulsation generating device. Background Art

[0002] In combustion engineering, gas flow pulsation generators are used to simulate and control air flow pulsation during the combustion process, which is essential for optimizing combustion efficiency, reducing emissions and improving combustion stability. There are two types of existing gas flow pulsation generators: One is: using a loudspeaker as a pulsation generator to generate flow pulsation, the device consists of a pulsation amplification module and a pulsation generation module. The pulsation amplification module includes at least one half-wavelength tube. The pulsation generation module includes a loudspeaker and a base, and a resonance cavity is formed between the loudspeaker and the base. The loudspeaker generates vibrations to convert the airflow in the resonance cavity into a pulsating airflow, and then the pulsation amplitude is adjusted by the pulsation amplification module. The other is: using a rotating shaft with a specific cross-section to insert into the combustion chamber outlet flow channel, the combustion chamber outlet area can be periodically changed by rotation to generate flow pulsation.

[0003] The loudspeaker as a gas flow pulsation generator can only handle small flow rates, and the actual effect is not good on devices that require large flow rates, such as combustion test benches; the whistle-type pulsation generator generally needs to be inserted into the combustion chamber flow channel from the radial direction, which is difficult to install and arrange, and is in a high-temperature, high-pressure, and high-turbulence environment, so thermal protection and sealing are difficult and the structure is complex. Based on this, it is necessary for the industry to provide a new gas flow pulsation generator. Summary of the invention

[0004] The present invention provides a gas flow pulsation generating device, which is used to solve the defects of the gas flow pulsation generating device in the prior art that it can only cope with small flow and is difficult to install and arrange.

[0005] The present invention provides a gas flow pulsation generating device, comprising: a generator body, a moving part and a driving mechanism; a first through hole is provided on an end face of one end of the generator body, the generator body has a first cavity, and the first cavity is connected to the first through hole; the first end of the moving part is located in the first through hole, the first end of the moving part is in a conical structure, and the moving part can reciprocate along the first through hole under the action of the driving mechanism, and the high-temperature combustion gas generated by the combustion chamber enters the first cavity through the gap between the conical structure and the first through hole.

[0006] According to a gas flow pulsation generating device provided by the present invention, the driving mechanism includes: a driver and a push rod, the driver is connected to the push rod, one end of the push rod extends into the first cavity and is connected to the moving part.

[0007] A gas flow pulsation generating device provided according to the present invention also includes a water inlet joint, a first flow channel is provided inside the push rod, and the water inlet joint is connected to the first flow channel; a second flow channel is provided inside the moving part, and the second flow channel is connected to the first flow channel; a plurality of second through holes are provided on the surface of the moving part, and the second through holes are connected to the second flow channel, and the second through holes are located in the first cavity.

[0008] According to a gas flow pulsation generating device provided by the present invention, the second flow channel includes: a main flow channel and multiple branch flow channels, the main flow channel is arranged at the center of the moving part, the main flow channel is connected to the first flow channel, and the multiple branch flow channels are arranged around the main flow channel, one end of each of the branch flow channels is connected to the main flow channel, and each of the branch flow channels and the other end of the branch flow channels are respectively connected to the second through hole.

[0009] According to a gas flow pulsation generating device provided by the present invention, it also includes a cooling element and a water inlet pipe, wherein the cooling element is sleeved on the outside of the moving element, the cooling element has a second cavity, the water inlet pipe is connected to the second cavity, and one end of the water inlet pipe extends to the outside of the generator body; a plurality of third through holes are provided on the surface of the cooling element, and the third through holes are connected to the second cavity.

[0010] According to a gas flow pulsation generating device provided by the present invention, some of the plurality of third through holes face the moving part, and the remaining third through holes face the end surface of the generator body where the first through hole is located.

[0011] According to a gas flow pulsation generating device provided by the present invention, the first through hole is a conical hole, and the conical direction of the conical hole is opposite to the conical direction of the moving part.

[0012] According to a gas flow pulsation generating device provided by the present invention, the generator body includes: a first flange, a second flange, a connecting pipe, an end plate and an exhaust pipe; the first flange is connected to the second flange through the connecting pipe, the interior of the connecting pipe has the first cavity, and the exhaust pipe is connected to the first cavity; the end plate is embedded in the first flange, and the end plate is provided with the first through hole; one end of the push rod passes through the second flange and is connected to the moving part.

[0013] A gas flow pulsation generating device provided according to the present invention also includes a gas sealing member, which is sleeved on the outside of the push rod and located outside the first cavity; the gas sealing member is connected to the second flange, and an air cavity is formed between the gas sealing member and the push rod.

[0014] According to the present invention, a gas flow pulsation generating device further includes a linear bearing, which is sleeved on the outside of the push rod and abuts against the gas sealing member.

[0015] The gas flow pulsation generating device provided by the present invention designs the first end of the moving part into a conical structure, and drives the moving part to move back and forth linearly along the first through hole through a driving mechanism to change the actual intake area of ​​the first through hole, thereby generating corresponding flow pulsation at the inlet of the combustion chamber. The gas flow pulsation generating device provided by the embodiment of the present invention can not only cope with large flow conditions, but also has a simple structure and low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a structural schematic diagram of the gas flow pulsation generating device provided by the present invention.

[0018] Figure 2 It is a cross-sectional view of the gas flow pulsation generating device provided by the present invention.

[0019] Figure 3 yes Figure 1 Schematic diagram of the structure of the moving parts shown in FIG.

[0020] Figure 4 yes Figure 2 A schematic diagram of the structure of the cooling element is shown in FIG.

[0021] Figure 5 It is the profile curve of the moving part.

[0022] Figure 6 It is the flow change curve of the moving parts as time goes by.

[0023] Reference numerals: 1. Generator body; 2. Moving parts; 3. Cooling parts; 4. Push rod; 5. Water inlet joint; 6. Air seal; 7. Linear bearing; 8. Water inlet pipe; 11. first flange; 12. connecting pipe; 13. second flange; 14. exhaust pipe; 15. end plate; 21. main flow channel; 22. branch flow channel; 31. third through hole; 41. first flow channel; 61. air cavity; 101, first through hole; 102, first cavity; 221, second through hole. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Combine the following Figure 1-Figure 6 The gas flow pulsation generating device of the present invention is described.

[0026] like Figure 1 and Figure 2 As shown, in an embodiment of the present invention, the gas flow pulsation generating device comprises: a generator body 1, a moving part 2 and a driving mechanism. A first through hole 101 is provided on one end face of the generator body 1, and the generator body 1 has a first cavity 102, and the first cavity 102 is connected to the first through hole 101. The first end of the moving part 2 is located in the first through hole 101, and the first end of the moving part 2 is in a conical structure. The moving part 2 can reciprocate along the first through hole 101 under the action of the driving mechanism.

[0027] Specifically, the gas flow pulsation generating device provided in the embodiment of the present invention is used to simulate the boundary conditions of the combustion dynamic characteristics test of the combustion chamber. The fuel burns in the combustion chamber, and the high-temperature combustion gas generated enters the first cavity 102 through the first through hole 101 and is then discharged. In the process of the high-temperature combustion gas entering the first cavity 102, the moving part 2 reciprocates along the first through hole 101 under the action of the driving mechanism. Since the first end of the moving part 2 is a conical structure, during the movement of the moving part 2, the area located in the first through hole 101 is different, resulting in different actual intake areas. Since the first through hole 101 is sonic, the critical condition is reached. When the total temperature and total pressure upstream of the first through hole 101 remain unchanged, the maximum flow rate through the first through hole 101 is only related to the actual intake area of ​​the first through hole 101. When the driving mechanism drives the moving part 2 to move periodically along the first through hole 101, the actual intake area of ​​the first through hole 101 will be changed, resulting in corresponding flow pulsation at the entrance of the combustion chamber, providing hardware support for the combustion dynamic characteristics test research of the combustion chamber. When the portion with the smallest cross-sectional dimension of the moving part 2 is located in the first through hole 101, the actual air intake area is the largest, and the flow rate of the high-temperature combustion gas entering the first cavity 102 is the largest, thereby being able to cope with the high-flow condition of the combustion chamber.

[0028] The gas flow pulsation generating device provided in the embodiment of the present invention designs the first end of the moving part into a conical structure, and drives the moving part to move back and forth linearly along the first through hole through a driving mechanism to change the actual intake area of ​​the first through hole, thereby generating corresponding flow pulsation at the inlet of the combustion chamber. The gas flow pulsation generating device provided in the embodiment of the present invention can not only cope with large flow conditions, but also has a simple structure and low manufacturing cost.

[0029] like Figure 2 As shown, in an embodiment of the present invention, the driving mechanism includes: a driver and a push rod 4, the driver is connected to the push rod 4, one end of the push rod 4 extends into the first cavity 102 and is connected to the moving part 2. In this embodiment, the driver can be a linear motor, and when the driver is running, it drives the push rod 4 to move, and then drives the moving part 2 to reciprocate linearly along the first through hole 101.

[0030] Optionally, in an embodiment of the present invention, the first through hole 101 may be a cylindrical hole; the first through hole 101 may also be a conical hole. When the first through hole 101 is a conical hole, the conical direction of the conical hole is opposite to the conical direction of the moving part 2, so that during the reciprocating motion of the moving part 2, the actual air intake area has multiple types, thereby being able to cope with working conditions of different flow rates.

[0031] like Figure 2 As shown, in an embodiment of the present invention, the gas flow pulsation generating device further includes a water inlet joint 5. A first flow channel 41 is provided inside the push rod 4, and the water inlet joint 5 is connected to the first flow channel 41. A second flow channel is provided inside the moving part 2, and the second flow channel is connected to the first flow channel 41. A plurality of second through holes 221 are provided on the surface of the moving part 2, and the second through holes 221 are connected to the second flow channel, and the second through holes 221 are located in the first cavity 102.

[0032] Specifically, the cooling water enters the first flow channel 41 from the water inlet joint 5 , then flows from the first flow channel 41 into the second flow channel, and is discharged from the second through hole 221 to cool the moving part 2 .

[0033] like Figure 3 As shown, in an embodiment of the present invention, the second flow channel includes: a main flow channel 21 and a plurality of branch flow channels 22, the main flow channel 21 is arranged at the center of the moving part 2, the main flow channel 21 is connected to the first flow channel, and the plurality of branch flow channels 22 are arranged around the main flow channel 21, one end of each branch flow channel 22 is connected to the main flow channel 21, and each branch flow channel 22 and the other end of the branch flow channel 22 are connected to the second through hole 221.

[0034] In this embodiment, each branch channel 22 is arranged close to the outer surface of the moving part 2. After the cooling water enters the main channel 21 from the first channel 41, it flows to each branch channel 22. Since the branch channel 22 is close to the surface of the moving part 2, it can play a good cooling effect on the moving part 2.

[0035] like Figure 2 As shown, in the embodiment of the present invention, the gas flow pulsation generating device further includes a cooling member 3 and a water inlet pipe 8, the cooling member 3 is sleeved on the outside of the moving member 2, the cooling member 3 has a second cavity, the water inlet pipe 8 is connected to the second cavity, and one end of the water inlet pipe 8 extends to the outside of the generator body 1. A plurality of third through holes 31 are provided on the surface of the cooling member 3, and the third through holes 31 are connected to the second cavity.

[0036] Specifically, the cooling member 3 is sleeved on the outside of the moving member 2 with a distance therebetween. The cooling member 3 is arranged adjacent to the first through hole 101, and cooling water enters the second cavity of the cooling member 3 through the water inlet pipe 8 and then sprays out through the third through hole 31 to cool the end surface of the generator body 1.

[0037] Furthermore, if Figure 4 As shown, some of the multiple third through holes 31 are arranged toward the moving part 2 to cool the moving part 2; the remaining third through holes 31 are arranged toward the end surface of the generator body 1 where the first through hole 101 is located to cool the end surface.

[0038] Optionally, in an embodiment of the present invention, the cooling member 3 is an annular regular polygonal structure, such as a regular octagonal structure, and each hollow rod of the regular octagonal structure is provided with a pair of third through holes 31, one third through hole 31 faces the moving member 2, and one third through hole 31 faces the end plate 15. Optionally, the diameter of each third through hole 31 is 1.5 mm.

[0039] The gas flow pulsation generating device provided in the embodiment of the present invention can cool the end faces of the moving part and the generator body by setting a first flow channel inside the push rod, setting a second flow channel inside the moving part, and setting a cooling part in the first cavity, thereby ensuring that the outer surface temperature of the moving part is within a safe range and is not burned, thereby ensuring that the moving part can be used for a long time.

[0040] like Figure 2 As shown, in the embodiment of the present invention, the generator body 1 includes: a first flange 11, a connecting pipe 12, a second flange 13, an exhaust pipe 14 and an end plate 15. The first flange 11 is connected to the second flange 13 through the connecting pipe 12, the interior of the connecting pipe 12 has a first cavity 102, and the exhaust pipe 14 is connected to the first cavity 102. The end plate 15 is embedded in the first flange 11, and the end plate 15 is provided with a first through hole 101, and one end of the push rod 4 passes through the second flange 13 and is connected to the moving part 2.

[0041] Specifically, the high temperature combustion gas generated in the combustion chamber enters the first cavity 102 through the first through hole 101 and is then discharged through the exhaust pipe 14. In this embodiment, the first through hole 101 is formed on the end plate 15, so part of the third through holes 31 of the cooling member 3 are disposed toward the end plate 15 to cool the end plate 15.

[0042] like Figure 2 As shown, in an embodiment of the present invention, the gas flow pulsation generating device further includes a gas seal 6, which is sleeved on the outside of the push rod 4 and is located outside the first cavity 102. The gas seal 6 is connected to the second flange 13, and an air cavity 61 is formed between the gas seal 6 and the push rod 4. When the driver drives the push rod 4 to reciprocate linearly, the high-temperature combustion gas in the first cavity 102 flows into the air cavity 61 as the push rod 4 is twitched.

[0043] like Figure 2 As shown, in an embodiment of the present invention, the gas flow pulsation generating device further comprises a linear bearing 7, which is sleeved on the outside of the push rod 4 and abuts against the gas seal 6. The gas cavity 61 of the gas seal 6 can prevent high-temperature combustion gas from entering the linear bearing 7.

[0044] In the embodiment of the present invention, the conical surface parameter design process of the moving part 2 is as follows: The key parameter for the design of the end plate 15 is the diameter of the first through hole 101. When the airflow in the first through hole 101 is in a critical state, its flow rate The calculation formula is:

[0045] in, is the specific heat ratio, R is the gas constant, is the total pressure at the combustion chamber outlet, is the total temperature, is the flow coefficient, is the first through hole area, is the flow function.

[0046] The motion curve of the driver is: (2) in, x is the travel of the drive, f is the frequency, t The time it takes for a moving part to move.

[0047] When the moving member 2 moves in the first through hole 101, the effective flow area of ​​the first through hole 101 for:

[0048] in, is the area of ​​the first through hole, and r is the radius of the cross section of the moving part in the first through hole. To make the generated flow cosine pulsation, the flow area The change of must be a cosine change. The area of ​​the first through hole remains unchanged, so the radius of the cross section of the moving part 2 located in the first through hole 101 must satisfy the cosine change over time. Suppose the general equation it satisfies is:

[0049] in, is the speed of the moving part, is the time for the moving part to move, a, b, c is the profile parameter of the moving part. Since the frequency of the motion curve of the driver is consistent with the frequency of the required flow pulsation, it can be set as follows:

[0050] but c =2.

[0051] From formula (2), we can get:

[0052] Substitute formula (5) and (6) into formula (4). We can get:

[0053] The remaining profile parameters a and b It is determined according to the flow pulsation curve.

[0054] In the first cavity 102, the cooling water of the cooling member 3 is sprayed into the high-temperature combustion gas, and the air temperature is rapidly reduced by evaporation and heat absorption. Therefore, the heat transfer of the push rod 4 in the first cavity 102 is negligible relative to the moving member 2, and the cooling of the front end is mainly considered. The cooling water enters the moving member 2 through the first flow channel 41, performs impact cooling on the moving member 2, and then sprays out from the second through hole 221 opened on the wall of the moving member 2 along the main flow channel 21 and each branch flow channel 22 inside the moving member 2.

[0055] Specifically, under the conditions of a combustion chamber inlet pressure of 0.5 MPa, a temperature of 600 K, and an average flow rate of 0.38 kg / s, the radius of the cross section of the moving part 2 located in the first through hole 101 when the external excitation frequency is 20 Hz and the relative amplitude of the flow rate is 20% is as follows: The geometric area of ​​the first through hole 101 is calculated by formula (1): =1057.78 mm 2 , and set the cross-sectional radius when the moving part 2 is in the initial positionr 0 =10 mm, then the diameter of the first through hole 101 D =41.78 mm.

[0056] The frequency of the selected drive f =20 Hz, stroke x =12.5 mm, the drive motion curve can be obtained as y =6.25(1-cos(2πft)).

[0057] To achieve a flow pulsation of 20%, the minimum flow rate can be calculated as 0.304 kg / s based on the maximum flow rate of 0.456 kg / s. Substituting the minimum flow rate into formula (1) can obtain the corresponding effective flow area At this time, the drive stroke reaches its maximum value. y =12.5 mm, and the effective flow area is substituted into formulas (3) and (7), and the parameters can be determined. a and b The equations satisfied are: . According to the maximum flow rate of 0.456 kg / s and the initial radius setting value of the moving part At this time, the drive stroke reaches the minimum value, that is y =0 mm, we can get: . From this we can conclude that the values ​​of a and b are: , .

[0058] Therefore, the radius equation of the cross section of the moving part 2 located in the first through hole 101 can be determined as follows:

[0059] Then the profile curve of moving part 2 is as follows Figure 5 As shown, ideally, the flow rate generated by the moving part 2 changes with time as shown in Figure 6 shown.

[0060] According to the above calculation, the radius of the cross section of the moving part 2 in the first through hole can be determined according to the required flow pulsation frequency and amplitude, as well as the frequency and stroke of the driver, according to formula (8). and the calculated , the conical structure of the moving part 2 can be determined.

[0061] The gas flow pulsation generating device provided in the embodiment of the present invention adopts a driver to drive the moving part to reciprocate to change the effective flow area of ​​the first through hole. It has a simple structure and low cost, and can stably generate low-frequency, high-amplitude, and specified waveform flow pulsation.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas flow pulsation generating device, characterized in that: include: A generator body, a moving part and a driving mechanism; a first through hole is provided on an end surface of one end of the generator body, the generator body has a first cavity, and the first cavity is connected to the first through hole; The first end of the moving part is located in the first through hole, and the first end of the moving part is a cone structure. Under the action of the driving mechanism, the moving part can reciprocate along the first through hole, and the high-temperature combustion gas generated by the combustion chamber enters the first cavity through the gap between the cone structure and the first through hole.

2. The gas flow pulsation generating device according to claim 1, characterized in that: The driving mechanism comprises: a driver and a push rod, wherein the driver is connected to the push rod, and one end of the push rod extends into the first cavity and is connected to the moving part.

3. The gas flow pulsation generating device according to claim 2, characterized in that: It also includes a water inlet joint, a first flow channel is provided inside the push rod, and the water inlet joint is communicated with the first flow channel; A second flow channel is provided inside the moving part, the second flow channel is communicated with the first flow channel, a plurality of second through holes are provided on the surface of the moving part, the second through holes are communicated with the second flow channel, and the second through holes are located in the first cavity.

4. The gas flow pulsation generating device according to claim 3, characterized in that: The second flow channel includes: a main flow channel and multiple branch flow channels, the main flow channel is arranged at the center of the moving part, the main flow channel is connected to the first flow channel, and the multiple branch flow channels are arranged around the main flow channel, one end of each of the branch flow channels is connected to the main flow channel, and each of the branch flow channels and the other end of the branch flow channels are respectively connected to the second through hole.

5. The gas flow pulsation generating device according to claim 1, characterized in that: It also includes a cooling member and a water inlet pipe, wherein the cooling member is sleeved on the outside of the moving member, the cooling member has a second cavity, the water inlet pipe is communicated with the second cavity, and one end of the water inlet pipe extends to the outside of the generator body; A plurality of third through holes are provided on the surface of the cooling member, and the third through holes are communicated with the second cavity.

6. The gas flow pulsation generating device according to claim 5, characterized in that: Some of the plurality of third through holes face the moving part, and the remaining third through holes face the end surface of the generator body where the first through hole is located.

7. The gas flow pulsation generating device according to claim 1, characterized in that: The first through hole is a conical hole, and the conical direction of the conical hole is opposite to the conical direction of the moving part.

8. The gas flow pulsation generating device according to claim 2, characterized in that: The generator body comprises: a first flange, a second flange, a connecting pipe, an end plate and an exhaust pipe; The first flange is connected to the second flange via the connecting pipe, the connecting pipe has the first cavity inside, and the exhaust pipe is in communication with the first cavity; The end plate is embedded in the first flange, and the end plate is provided with the first through hole; One end of the push rod passes through the second flange and is connected to the moving part.

9. The gas flow pulsation generating device according to claim 8, characterized in that: It also includes an air seal, which is sleeved on the outside of the push rod and located outside the first cavity; The gas sealing member is connected to the second flange, and an air cavity is formed between the gas sealing member and the push rod.

10. The gas flow pulsation generating device according to claim 9, characterized in that: It also includes a linear bearing, which is sleeved on the outside of the push rod and abuts against the gas seal.

Images