Simulation optimization method of combustor

Abstract

The invention discloses a simulation optimization method of a burner, which is used for simulating the burner of a simulation stove, and the simulation optimization method of the burner comprises the following steps: obtaining a complete machine model of the stove; based on a combustor model in the complete machine model, constructing an inner flow channel drainage basin comprising inner cavity fluid of a combustor; based on the model of the peripheral area of the inlet of the injection pipe in the complete machine model, constructing a primary air drainage basin comprising the peripheral area of the inlet of the injection pipe; carrying out analog simulation on a mixed drainage basin comprising an inner flow channel drainage basin and a primary air drainage basin; and optimizing the structure of the combustor based on the simulation result of the mixed drainage basin. Simulation is carried out by taking the inner flow channel drainage basin and the primary air drainage basin as the mixed drainage basin, and the fluid condition of the external peripheral area at the inlet of the injection pipe is introduced in the simulation process, so that the flow field characteristics of the simulation model are closer to and consistent with the actual condition, the simulation result is improved, and the structure optimization effect of the combustor can be improved.

Description

Technical Field

[0001] The present invention relates to a simulation optimization method for a burner. Background Art

[0002] In a burner of a domestic cooking appliance, the base, as its core component, plays a key role in connecting the ejector pipe and the flame holes and delivering gas and air. The main function of the base is to rectify the gas-air mixture to ensure the efficiency and stability of the combustion process. When the base cavity is designed wide enough, it can effectively convert the dynamic pressure of the mixture into static pressure, so that the mixture can flow out evenly from the flame holes, providing a stable gas supply for combustion. Therefore, the performance of the base is crucial for the efficient operation of the burner. However, the current methods for evaluating the performance of the base mainly rely on proofing and comparative tests. This method has certain blindness, a long test cycle and high costs, and is prone to waste of resources.

[0003] With the rapid development of technology, the method of combining simulation and experiment has been widely used in the field of product R & D. For a complex product like a burner with characteristics such as porous, low-pressure ejection, and internal and external mixing flow fields, using a general solution for simulation cannot accurately obtain the simulation results. How to construct unique physical and mathematical models according to its specific usage environment to obtain more accurate simulation results has become the focus of design and R & D by technicians. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defect that the simulation results of a burner in the prior art are inaccurate, and to provide a simulation optimization method for a burner.

[0005] The present invention solves the above technical problem through the following technical solutions:

[0006] A simulation optimization method for a burner, which is used to simulate a burner of a cooking appliance. The simulation optimization method for the burner includes the following steps:

[0007] Obtain the whole-machine model of the cooking appliance;

[0008] Based on the burner model in the whole-machine model, construct an internal flow channel flow field including the internal cavity fluid of the burner;

[0009] Based on the model of the area around the inlet of the ejector pipe in the whole-machine model, construct a primary air flow field including the area around the inlet of the ejector pipe;

[0010] Perform simulation on the mixed flow field including the internal flow channel flow field and the primary air flow field;

[0011] Optimize the structure of the burner based on the simulation results of the mixed flow field.

[0012] The simulation optimization method of this burner conducts simulation through the inner flow channel domain and the primary air domain as the mixing domains, and introduces the fluid conditions in the external peripheral area at the inlet of the ejector tube during the simulation, making the flow field characteristics of the simulation model closer to the actual situation, so as to improve the simulation results, and further improve the structural optimization effect of the burner.

[0013] Preferably, the inner flow channel domain includes the base of the burner and the inner cavity fluid of the ejector tube.

[0014] In setting the range of the inner flow channel domain to include the base of the burner and the ejector tube, the simulation results can be improved.

[0015] Preferably, the inner flow channel domain further includes the inner cavity fluid of one or more of the burner cap, mixing chamber, nozzle, and nozzle seat.

[0016] In setting the range of the inner flow channel domain to include one or more of the burner cap, mixing chamber, nozzle, and nozzle seat, the simulation results can be further improved.

[0017] Preferably, the upper wall surface of the primary air domain extends to the panel of the cooking stove.

[0018] In setting the range of the inner flow channel domain, making the upper wall surface of the primary air domain extend to the panel of the cooking stove can make the primary air domain more conform to the primary air flow condition around the inlet of the ejector tube, so as to further improve the simulation results.

[0019] Preferably, the lower wall surface of the primary air domain extends to the chassis of the cooking stove.

[0020] In setting the range of the inner flow channel domain, making the lower wall surface of the primary air domain extend to the chassis of the cooking stove can make the primary air domain more conform to the primary air flow condition around the inlet of the ejector tube, so as to further improve the simulation results.

[0021] Preferably, the front wall surface of the primary air domain extends to the burner head support.

[0022] In setting the range of the inner flow channel domain, making the front wall surface of the primary air domain extend to the burner head support can make the primary air domain more conform to the primary air flow condition around the inlet of the ejector tube, so as to further improve the simulation results.

[0023] Preferably, the rear wall surface of the primary air domain extends to the intake end face of the burner nozzle and / or nozzle seat.

[0024] When setting the range of the internal flow channel basin, extending the lower wall surface of the primary air basin to the rear wall surface and further to the air inlet end surface of the burner nozzle and / or nozzle seat can make the primary air basin more conform to the primary air flow condition around the inlet of the ejector tube, so as to further improve the simulation results.

[0025] Preferably, in the step of simulating the mixed basin including the internal flow channel basin and the primary air basin, it specifically includes:

[0026] Setting the gas inlet, air inlet and air flow outlet of the mixed basin based on the flow paths of gas and air in the cooking appliance;

[0027] Solving the steady state of one or more of fluid velocity, pressure, density and component concentration for the mixed basin.

[0028] By solving the steady state of one or more of fluid velocity, pressure, density and component concentration for the mixed basin, different flow field parameters can be obtained to more comprehensively optimize the structure of the burner.

[0029] Preferably, in the step of setting the gas inlet, air inlet and air flow outlet of the mixed basin based on the flow paths of gas and air in the cooking appliance, it specifically includes:

[0030] The pressure of the gas inlet is 2000 Pa; and / or,

[0031] The pressure of the air inlet is 0 Pa; and / or,

[0032] The pressure of the air flow outlet is 0 Pa.

[0033] By reasonably setting the pressure values of the gas inlet, air inlet and air flow outlet, the simulation results can be further improved.

[0034] Preferably, in the step of setting the gas inlet, air inlet and air flow outlet of the mixed basin based on the flow paths of gas and air in the cooking appliance, it specifically includes:

[0035] The gas inlet contains at least natural gas; and / or,

[0036] The gas components of the gas inlet are defined based on the actually measured gas components.

[0037] By reasonably setting the gas components of the gas inlet, the simulation results can be further improved.

[0038] Preferably, in the step of optimizing the structure of the burner based on the simulation results of the mixed basin, it specifically includes:

[0039] Optimize the structure of the low-flow-rate region of the burner base based on the velocity contour map in the simulation results.

[0040] By optimizing the structure of the low-flow-rate region, the low-flow-rate region can be effectively eliminated, the generation of flow dead zones can be avoided, and thus the generation of eddy currents can be alleviated. Compared with optimizing other structures of the burner, optimizing the base has a relatively greater impact on the fluid, and the position of the base is relatively far from the flame holes, so the adjustment of its structure will not have a great impact on the layout of the flame on the burner cap.

[0041] Preferably, in the step of optimizing the structure of the low-flow-rate region of the burner base based on the velocity contour map in the simulation results, it specifically includes:

[0042] Optimize the structure of the low-flow-rate region of the base by filling the low-flow-rate region by adjusting the wall surface of the base.

[0043] The method of adjusting the position of the base wall surface is simple and reliable, and can effectively optimize the low-flow-rate region of the base. Compared with other optimization schemes such as increasing the wall thickness to fill the low-flow-rate region, it can effectively avoid a large increase in the mass of the base.

[0044] Preferably, in the step of optimizing the structure of the burner based on the simulation results of the mixed flow domain, it specifically includes: optimizing the structure of the burner base.

[0045] The structure of the burner base has an important influence on fluid flow. By analyzing the simulation results, the flow conditions of the fluid near the base can be understood, including the distribution of parameters such as velocity, pressure, and temperature. By optimizing the design of the base structure, the fluid flow path can be adjusted to make the fluid more evenly distributed into the combustion chamber and improve the combustion efficiency. Compared with optimizing other structures of the burner, optimizing the base has a relatively greater impact on the fluid, and the position of the base is relatively far from the flame holes, so the adjustment of its structure will not have a great impact on the layout of the flame on the burner cap.

[0046] The positive and progressive effects of the present invention are as follows:

[0047] In the simulation optimization method of the burner, by using the internal flow channel domain and the primary air domain as the mixed domain for simulation, and introducing the fluid conditions in the external peripheral region at the inlet of the ejector tube during the simulation, the flow field characteristics of the simulation model are made closer to the actual situation, so as to improve the simulation results, and further improve the effect of optimizing the structure of the burner. Description of the Drawings

[0048] Figure 1 It is a flowchart of the steps of the simulation optimization method of the burner according to an embodiment of the present invention.

[0049] Figure 2aSchematic diagram of a hybrid basin according to an embodiment of the present invention.

[0050] Figure 2b Schematic diagram of a hybrid basin according to an embodiment of the present invention, wherein the internal structure of the model is shown by a dashed line.

[0051] Figure 3 Schematic diagram of the positions of the walls of the primary air basin of a hybrid basin according to an embodiment of the present invention.

[0052] Figure 4 Schematic diagram of the mesh division of a hybrid basin according to an embodiment of the present invention.

[0053] Figure 5 Horizontal cross-sectional velocity cloud diagram of the base cavity according to an embodiment of the present invention.

[0054] Figure 6 Schematic diagram of the optimized structure of the base of a burner according to an embodiment of the present invention.

[0055] Figure 7 is Figure 6 Cross-sectional view of the base in

[0056] Figure 8a is Figure 6 Velocity cloud diagram of the base before optimization in

[0057] Figure 8b is Figure 6 Velocity cloud diagram of the base after optimization in

[0058] Explanation of reference numerals:

[0059] Inner flow channel basin 10

[0060] Primary air basin 20

[0061] Upper wall surface 201, lower wall surface 202, front wall surface 203, rear wall surface 204

[0062] Hybrid basin 100

[0063] Base 1

[0064] Wall surface 11 Detailed implementation manners

[0065] The present invention will be further described below by way of embodiments, but the present invention is not limited to the scope of the described embodiments.

[0066] The present invention provides a simulation optimization method for a burner, which is used to simulate a burner of a cooking stove. As Figure 1 shown, the simulation optimization method of the burner specifically includes the following steps:

[0067] S1. Obtain the overall model of the cooking appliance.

[0068] S2. Based on the burner model in the overall model, construct an internal flow channel domain that at least includes the internal cavity fluid of the burner.

[0069] S3. Based on the model of the peripheral area around the inlet of the ejector tube in the overall model, construct a primary air domain that at least includes the peripheral area around the inlet of the ejector tube.

[0070] S4. Perform simulation on the mixed domain that includes the internal flow channel domain and the primary air domain.

[0071] S5. Optimize the structure of the burner based on the simulation results of the mixed domain.

[0072] In this simulation optimization method for the burner, the internal flow channel domain 10 and the primary air domain 20 are used as the mixed domain 100 for simulation. During the simulation process, the fluid condition of the external peripheral area at the inlet of the ejector tube is introduced, making the flow field characteristics of the simulation model closer to the actual situation, so as to improve the simulation results, and further improve the effect of optimizing the structure of the burner.

[0073] Among them, there is no necessary sequence relationship between the implementation orders of step S2 and step S3. In other embodiments, step S2 and step S3 can be carried out successively or simultaneously.

[0074] Such as Figure 2a and 2b shown, it is the mixed domain 100 for fluid simulation constructed based on the overall model of the cooking appliance obtained in this embodiment. Among them, the internal flow channel domain 10 refers to the main area where the gas flows inside the burner, and should at least include the base of the burner and the internal cavity fluid of the ejector tube, so as to objectively reflect the gas flow inside the burner. More preferably, the internal flow channel domain 10 further includes the internal cavity fluid of one or more of the burner cap, mixing chamber, nozzle, and nozzle seat, so as to further improve the simulation results. Specifically, in this embodiment, the internal flow channel domain 10 includes the nozzle seat, nozzle, ejector tube, base, mixing chamber, and burner cap of the burner, so as to objectively reflect the situation where the gas enters the nozzle seat and then flows through the nozzle, ejector tube, base, and mixing chamber in sequence, and finally flows out from the burner cap.

[0075] In addition, as Figure 2a and 2b shown, the primary air domain 20 is located on the outer peripheral side of the internal flow channel domain 10 corresponding to the nozzle seat, nozzle, and ejector tube, so as to objectively reflect the fluid condition of the external peripheral area at the inlet of the ejector tube. In this embodiment, for the convenience of simulation, the outer wall surfaces of the primary air domain 20 are all planes. Among them, as Figure 3As shown in the figure, the upper wall surface 201 of the primary air domain 20 extends to the panel of the cooking appliance, the lower wall surface 202 extends to the chassis of the cooking appliance, the front wall surface 203 extends to the burner head support, and the rear wall surface 204 extends to the intake end surface of the burner nozzle seat, so as to balance the size of the primary air domain 20. On the one hand, it avoids the situation that the range of the primary air domain 20 is too large, resulting in too slow calculation and analysis speed. On the other hand, it also avoids the situation that the range of the primary air domain 20 is too small, affecting the simulation accuracy. In other embodiments, if the inner flow channel domain 10 does not include the inner cavity fluid in the nozzle seat, then the rear wall surface 204 of the primary air domain 20 can extend to the intake end surface of the nozzle.

[0076] In this embodiment, after obtaining the model of the mixing domain 100, it is necessary to perform mesh division on it. The specific mesh division is as Figure 4 shown. The density cores are distributed at the positions of the burner cap and the nozzle. The number of tetrahedral meshes is about 5 million, and the mesh orthogonality quality is greater than 0.11. In the analysis software, after converting the tetrahedral meshes into polyhedral meshes, the number of meshes can be reduced to 1 / 8 of the previous number. If the quality is lower than 0.1, it is necessary to topologize the mesh quality to above 0.1 to avoid non-convergence of the analysis due to poor mesh quality. By adjusting the mesh division of the mixing domain 100, the meshes are arranged in a proper density. While the accuracy of the simulation results meets the requirements, the number of meshes is small and the analysis is fast.

[0077] This simulation optimization method for the burner specifically includes the following specific steps in step S4:

[0078] S41. Set the gas inlet, air inlet, and air flow outlet of the mixing domain based on the flow paths of gas and air in the cooking appliance.

[0079] S42. Solve the steady state of the mixing domain based on one or more of fluid velocity, pressure, density, and component concentration.

[0080] In this embodiment, the model of the mixing domain 100 is provided with an air inlet, a gas inlet, and an air flow outlet. Among them, the pressure of the air inlet is 0 Pa, the pressure of the gas inlet is 2000 Pa, and the pressure of the air flow pressure outlet is 0 Pa. The gas inlet is located on the intake end surface of the nozzle seat, and the air flow pressure outlet is located at the end of the burner holes of the burner cap. The air inlets are located on the outer wall surfaces of the primary air domain 20. Among them, the gas inlet contains at least natural gas. Specifically, in this embodiment, the gas components of the gas inlet are defined based on the actually measured components of the gas, and the components of various gases in the gas are reflected in the form of percentage content.

[0081] In addition, in terms of other simulation setting parameters, there are also relatively preferred setting solutions in this embodiment to better match the operating conditions of the cooking appliance. Specifically, the turbulent model used in the simulation is Realizable k-ε, the wall function is Standard Wall Functions, and the species transport equation is Transport species. The Solution Methods are set by default. In the Solution Controls list, the residual of the species is set to 0.9, and the others are set by default. In addition, the wall temperature of each component 15 minutes after the burner is ignited needs to be input in the boundary conditions. (The selection of 15 minutes is to match the moment for measuring the flue gas value of the whole machine combustion stipulated in the national standard. The flow field condition at this moment is what this embodiment needs to simulate.)

[0082] This method for simulating and optimizing the burner specifically includes the following steps in step S5:

[0083] S51. Obtain the velocity contour map in the simulation results.

[0084] S52. Optimize the structure of the low-flow velocity region of the base of the burner based on the velocity contour map.

[0085] By optimizing the structure of the low-flow velocity region, the low-flow velocity region can be effectively eliminated, the generation of flow dead zones can be avoided, and thus the generation of eddy currents can be alleviated. Among them, in this embodiment, the specific object of structure optimization is the base. Compared with optimizing other structures of the burner, optimizing the base has a relatively greater impact on the fluid, and the position of the base is relatively far from the flame holes, and its structural adjustment will not have a greater impact on the layout of the flame on the burner cap.

[0086] As Figure 5 shown, it is the velocity contour map of the horizontal cross-section of the base cavity. It can be seen that the gas flow velocity of the part marked by the elliptical frame line on the right is relatively slow, there is a flow dead zone, which is a region with relatively unreasonable structure and needs to optimize and remove the fluid here.

[0087] The structure of the optimized base 1 is as shown in Figure 6 and Figure 7 shown. There is a wall surface 11 in this region of the base 1. On the basis of the original structure, move the wall surface 11 to the right in the direction indicated by the arrow in Figure 7 to obtain the optimized structure of the base 1. By filling the low-flow velocity region shown in the velocity contour map with the wall surface 11, the structure of the low-flow velocity region of the base 1 is optimized. This way of adjusting the position of the wall surface 11 of the base 1 is simple and reliable, and can effectively optimize the low-flow velocity region of the base 1. Compared with other optimization schemes such as increasing the wall thickness to fill the low-flow velocity region, it can effectively avoid a large increase in the mass of the base 1.

[0088] CompareFigure 8a and Figure 8b It can be seen that by adjusting the position of the wall surface 11 of the base 1, the structure of the low-flow velocity region is optimized. Figure 8b In the velocity contour diagram of [], the eddy current on the right side has disappeared, and the calculated entrainment coefficient can be increased by 2%.

[0089] Of course, the above optimization scheme is only for illustration. In other embodiments, it is also possible to analyze based on the pressure contour diagram, density contour diagram, or even the gas component concentration contour diagram obtained from the simulation to diagnose the unreasonable parts of the structure and optimize the structure accordingly to improve the performance of the burner.

[0090] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that this is only an example. The protection scope of the present invention is defined by the appended claims. Without departing from the principle and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A burner simulation optimization method, which is used to simulate the burner of a simulated stove, characterized in that: The burner simulation optimization method comprises the following steps: Get the whole machine model of the stove; Based on the burner model in the whole machine model, an inner flow channel domain including the inner cavity fluid of the burner is constructed; Based on the model of the area around the ejector pipe inlet in the whole machine model, a primary air flow domain including the area around the ejector pipe inlet is constructed; Simulate the mixed flow area including the inner flow channel flow area and the primary air flow area; The structure of the burner is optimized based on the simulation results of the mixed flow domain.

2. The burner simulation optimization method according to claim 1, characterized in that: The inner flow channel flow area includes the base of the burner and the inner cavity fluid of the ejector tube.

3. The burner simulation optimization method according to claim 2, characterized in that: The inner flow channel flow area also includes the inner cavity fluid of one or more of the fire cover, the air mixing chamber, the nozzle and the nozzle seat of the burner.

4. The burner simulation optimization method according to claim 1, characterized in that: The upper wall surface of the primary air flow region extends to the panel of the cooker; And / or, the lower wall surface of the primary air flow region extends to the bottom plate of the cooker; And / or, the front wall surface of the primary air flow region extends to the burner head support of the burner; And / or, the rear wall surface of the primary air flow region extends to the air inlet end surface of the burner nozzle and / or the nozzle seat.

5. The burner simulation optimization method according to claim 1, characterized in that: The step of simulating the mixed flow area including the inner flow channel flow area and the primary air flow area specifically includes: The gas inlet, the air inlet and the air flow outlet of the mixing flow area are arranged based on the flow paths of the gas and the air in the cooker; The mixing flow domain is solved for a steady state based on one or more of fluid velocity, pressure, density, and component concentration.

6. The burner simulation optimization method according to claim 5, characterized in that: The step of setting the gas inlet, the air inlet and the air flow outlet of the mixed flow area based on the flow paths of the gas and the air in the cooker specifically includes: The gas inlet pressure is 2000 Pa; and / or, The pressure of the air inlet is 0 Pa; and / or, The pressure at the air flow outlet is 0Pa.

7. The burner simulation optimization method according to claim 5, characterized in that: The step of setting the gas inlet, the air inlet and the air flow outlet of the mixed flow area based on the flow paths of the gas and the air in the cooker specifically includes: The gas inlet contains at least natural gas; and / or, The gas composition of the fuel gas inlet is defined based on the measured composition of the fuel gas.

8. The burner simulation optimization method according to claim 1, characterized in that: The step of optimizing the structure of the burner based on the simulation result of the mixed flow domain specifically includes: The structure of the low velocity area of ​​the burner base is optimized based on the velocity cloud diagram in the simulation results.

9. The burner simulation optimization method according to claim 8, characterized in that: The step of optimizing the structure of the low flow velocity area of ​​the base of the burner based on the velocity cloud map in the simulation result specifically includes: The low flow velocity area is filled by adjusting the wall surface of the base to optimize the structure of the low flow velocity area of ​​the base.

10. The burner simulation optimization method according to any one of claims 1 to 9, characterized in that: The step of optimizing the structure of the burner based on the simulation result of the mixed flow domain specifically includes: optimizing the structure of the base of the burner.

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