A combustion chamber wall surface pit array structure design method and combustion chamber

Abstract

The present invention discloses a method for designing a combustion chamber wall surface pit array structure and a combustion chamber. The method comprises: extracting a three-dimensional fluid model and conducting bench tests; establishing and verifying an in-cylinder combustion and emission simulation model; conducting bench tests on the cylinder head, piston, and cylinder liner; establishing and verifying a heat transfer simulation model; establishing a thermal-engine coupling simulation model; performing parameterized design on the pit array structure on the piston, cylinder liner, and cylinder head, establishing a collaborative optimization mathematical model for the pit array structure design, obtaining an optimal solution set, and selecting a typical solution; processing key components from the typical solution and conducting an installation test, and obtaining the optimal pit array structure design scheme through the test. The pit array structure obtained by the collaborative optimization design method of the present invention can not only reduce the weight of the components, but also form a turbulent layer near the wall of the combustion chamber to promote oil-gas mixing, thereby reducing nitrogen oxides and particulate matter, and thus improving the combustion performance of the engine.

Description

Technical Field

[0001] The present invention relates to an engine combustion chamber, and in particular to a method for collaboratively optimizing the design of a pit array structure on a combustion chamber wall surface and the combustion chamber. Background Art

[0002] In recent years, reducing carbon emissions has become a common pursuit of the world, which requires engines to continue to develop in the direction of low carbonization, cleaning and lightweight.

[0003] To meet these development needs, improving engine power density and combustion explosion pressure has become the focus of research. Therefore, developing efficient and clean combustion systems is the key to achieving these development requirements.

[0004] CN114526151A discloses a combustion chamber and a diesel engine, wherein the bottom of the combustion chamber recess includes an upwardly protruding, rotary central protrusion and a circumferential annular recess surrounding the central protrusion. The recess in this patent is annular and located only on the piston structure, which inherently fails to achieve the goal of reducing component weight. CN115355082A discloses a combustion chamber structure for a gas engine with an accelerated combustion function, wherein the combustion chamber recess is located on the piston top. However, the recess in this patent is arc-shaped and connected to a flow-increasing port, lacking an array feature. CN114810329A discloses a combustion chamber and a gas engine, wherein the circumferential wall of the combustion chamber recess includes two main tumble guide walls and two cross tumble guide walls that alternate and smoothly connect along the circumference. The two main tumble guide walls and the bottom surface of the combustion chamber recess together form an open recess structure, while the two cross tumble guide walls and the bottom surface of the combustion chamber recess together form a constricted recess structure. The pits in this patent are only on the piston structure, and this structure is only a variation of the piston combustion chamber structure, and does not achieve the goal of reducing the weight of the piston. CN117128105A discloses a piston, a combustion chamber, and an engine. The top surface of the piston is provided with a combustion chamber pit, and the side walls of the piston surrounding the combustion chamber pit are provided with multiple flow channels. The pits in this patent are only on the piston structure, and the pit structure is accompanied by a flow channel structure. There is no optimization of the position, shape, number, etc. of the pits. CN 117108395A discloses a combustion chamber, a combustion system, a design method thereof, and an engine. The combustion chamber pit is alternately provided with ridges protruding toward the central axis of the combustion chamber and indentations recessed away from the central axis of the combustion chamber on the circumferential side walls surrounding the center boss. The indentations in this patent are only on the piston structure, and do not achieve the goal of reducing the weight of the components. CN213510911U discloses a piston and a diesel engine having the same, wherein the top surface of the piston is provided with a plurality of arcuate pits along the circumferential direction of the piston, the wall surface of one end of the arcuate pit is arcuate, and the other end is connected to the circular pit. The pits in this patent are in an arcuate structure and are connected to the circular pits, and the number and position of the pits are correlated with the number and position of the injection beams. CN113389634 A discloses a squeeze flow high turbulence centrifugal piston combustion chamber and combustion system, wherein the combustion chamber is composed of a plurality of pits, wherein the plurality of pits are connected to each other on the side near the center of the piston, and the plurality of pits are spaced apart on the side near the outer edge of the piston. The pit structure in this patent is merely a variation on the structure of the piston combustion chamber and does not achieve the goal of reducing the weight of the piston.

[0005] In summary, current dimple designs for combustion chamber walls are limited to piston components. Most piston dimple structures are merely variations of the piston head structure, lacking array features and lacking optimization of the position, shape, or number of dimples. Ultimately, this approach fails to achieve the goal of reducing piston weight. Therefore, to fully enhance combustion system efficiency and achieve component lightweighting, it is crucial to incorporate dimple structures into combustion chamber wall components. This provides technical support and theoretical foundation for the development and optimized design of engine combustion chamber systems.

[0006] The current pit design of the combustion chamber has the following main deficiencies:

[0007] 1) The dimples were only placed on the piston, one of the combustion chamber components, without a systematic analysis of the dimple structure. This made it impossible to determine whether the introduction of the dimples had a positive or negative impact on the entire combustion chamber system.

[0008] 2) There is no optimization of the position, shape, number, etc. of the pits, especially the coordinated optimization design of the combustion and emission performance, heat transfer and reliability of the combustion chamber system;

[0009] 3) There is no effort to achieve lightweighting of key components that make up the combustion chamber. Summary of the Invention

[0010] This invention addresses the challenges of existing technologies by providing a collaborative optimization design method for combustion chamber wall dimple arrays. Through a systematic approach involving experimental testing, simulation modeling and analysis, and re-testing optimization solutions, this method forms a complete and effective collaborative optimization design method for combustion chamber wall dimple arrays. This method can provide technical support and a theoretical basis for the development and optimization design of engine combustion chamber systems.

[0011] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions:

[0012] A collaborative optimization design method for a combustion chamber wall pit array structure comprises the following steps:

[0013] Step 1: extracting a three-dimensional fluid model of the combustion chamber from the assembled three-dimensional solid model of the engine;

[0014] Step 2: Perform a bench test on the engine to obtain the in-cylinder pressure curve, heat release rate curve, and power, economy, and emission performance indicators;

[0015] Step 3: Establish an engine cylinder combustion and emission simulation model and perform solver settings and calculations; verify the accuracy of the engine cylinder combustion and emission simulation model through experimental data obtained;

[0016] Step 4: Perform a temperature field bench test on the cylinder head, piston, and cylinder liner of the engine;

[0017] Step 5: Establish heat transfer simulation models for the key components related to the combustion chamber, including the piston, cylinder liner, and cylinder head, and perform solver settings and calculations.

[0018] Step 6: Verify the accuracy of the heat transfer simulation model of the piston, cylinder liner, and cylinder head through temperature field tests of key components;

[0019] Step 7: Establish a thermal-engine coupling simulation model of the key components related to the combustion chamber, including the piston, cylinder liner, and cylinder head, and perform solver settings and calculations;

[0020] Step 8: Parametrically design the pit array structure on the piston, cylinder liner, and cylinder head to create a sufficiently large design space;

[0021] Step 9: For each sample point in the design space, extract a three-dimensional fluid model according to step 1, establish an engine in-cylinder combustion and emission simulation model, set up and calculate the solver, and extract characteristic parameters representing the combustion performance and emission performance of each sample point;

[0022] Step 10: Further establish heat transfer simulation models and thermal-mechanical coupling simulation models of key combustion chamber components, such as piston, cylinder liner, and cylinder head, for each sample point in the design space according to step 5, set up and calculate the solver, and extract characteristic parameters representing heat transfer characteristics and reliability performance of each sample point;

[0023] Step 11: Establish a collaborative optimization mathematical model for the pit array structure design, obtain the optimal solution set, and select no less than 3 groups of typical solutions.

[0024] Step 12: Use 3D printing technology to process the key components of the typical solution, such as the piston, cylinder liner, and cylinder head.

[0025] Step 13: Install the newly designed key components and repeat the tests of steps 3 and 4.

[0026] Step 14: Obtain the best design scheme of the pit array structure by comparing the experimental data.

[0027] Furthermore, the three-dimensional fluid model in step 1 is composed of the piston top surface, cylinder wall, cylinder head, intake duct, exhaust duct, intake valve, exhaust valve, intake inlet, exhaust outlet, etc.

[0028] Furthermore, the power, economy and emission performance indicators tested by the engine bench test in step 2 mainly include speed, torque and power, fuel consumption rate, engine oil consumption, CO emissions, NO xEmissions, HC emissions, smoke density, etc.

[0029] Furthermore, after the calculation of the combustion and emission simulation model in the engine cylinder is completed in step 3, the cylinder pressure curve under the last working cycle is extracted and compared with the test data under the same working conditions. The verification standard is: the relative error between the simulation value and the test value is ≤ 5%.

[0030] Furthermore, in step 4, the temperature field test measurement points should be arranged on the actual cylinder head in a circular pattern centered on the nose bridge area of ​​the cylinder head's firepower surface. There should be no fewer than four measurement points. The temperature field test measurement points should be arranged on the actual cylinder liner in a circular pattern, including those corresponding to the piston at top dead center, bottom dead center, and mid-run. There should be no fewer than three measurement points. The temperature field test measurement points should be arranged on the actual piston in a circular pattern centered on the combustion chamber. There should be no fewer than three measurement points.

[0031] Furthermore, in step 5, the heat transfer simulation model of the piston, cylinder liner and cylinder head adopts the third type of thermal boundary loading convection heat transfer coefficient and surface temperature.

[0032] Furthermore, the verification standard for the accuracy of the heat transfer simulation model of the piston, cylinder liner and cylinder head in step 6 is: the relative error between the simulation value and the test value is ≤ 5%.

[0033] Furthermore, the gas pressure loading values ​​of the piston, cylinder liner and cylinder head in step 7 depend on the specific test conditions, and the test conditions should include at least one operating point, namely the maximum torque operating point or the calibration operating point.

[0034] Furthermore, in step 8, a dimple array structure is arranged on the top surface of the piston combustion chamber, the firing surface of the cylinder head, and the inner wall of the cylinder liner. The dimple array structure is determined by the location, size, and shape of the dimples. The location of the dimples on the piston and cylinder head is based on the center of the physical structure, with an initial dimple structure set at varying distances from the center. There are at least two initial dimple structures. The dimples are shaped like a sphere, cone, cylinder, polygon, or any combination thereof. Furthermore, with the center being the designated point, the dimples are arranged evenly around the circumference of the circle, with at least four dimples per circle. Furthermore, a dimple structure is arranged on the physical portion of the cylinder liner above the piston top dead center. The dimples are shaped like a sphere, cone, cylinder, polygon, or any combination thereof. Furthermore, the dimple structures are located on the same horizontal plane and evenly distributed around the circumference, with at least four dimples per circle. Furthermore, the dimple structure should be arranged on at least one physical object.

[0035] Furthermore, the characteristic parameters characterizing the combustion performance and emission performance directly extracted or indirectly calculated by the simulation model in step 9 include the in-cylinder pressure curve, the in-cylinder heat release rate curve, the in-cylinder average temperature curve, the in-cylinder average turbulent kinetic energy curve, the indicated fuel consumption, the indicated thermal efficiency, CO emissions, NOx emissions, HC emissions, smoke density, etc.

[0036] Furthermore, in step 10, the characteristic parameters characterizing the heat transfer characteristics and reliability performance directly extracted or indirectly calculated by the simulation model include the maximum temperature, maximum thermal stress, maximum thermal-mechanical coupling stress, minimum safety factor, etc.

[0037] Furthermore, the objective function in the collaborative optimization mathematical model of the dimple array structure design in step 11 should include indicated thermal efficiency, maximum thermal stress, and minimum safety factor.

[0038] Furthermore, the software involved in the collaborative optimization of the pit array structure include CONVERGE, UG, HYPERMESH, ABAQUS, FEMFAT, and MATLAB.

[0039] Furthermore, the UG software was used to complete the three-dimensional parametric modeling of the real object and the extraction of the fluid domain and other model processing work; the CONVERGE software was used to complete the establishment of the in-cylinder combustion and emission simulation model; the HYPERMESH software was used to complete the division of the component mesh; and the ABAQUS software was used to complete the establishment of the piston, cylinder liner and cylinder head heat transfer simulation model and thermal-mechanical coupling simulation; the FEMFAT software was used to calculate the reliability index of the components, that is, the minimum safety factor, and finally the MATLAB software was used to complete the construction of the collaborative optimization mathematical model of the pit array structure design.

[0040] The beneficial effects of the present invention include:

[0041] By setting up a pit array structure on the piston, cylinder liner and cylinder head, and combining parametric modeling, simulation analysis, experimental testing and other means, a complete and effective collaborative optimization design method for the combustion chamber wall pit array structure has been formed. This method can objectively, systematically and quantifiably verify the effectiveness of the structural design, and can provide technical support and theoretical basis for the development and optimization design of the engine combustion chamber system. Specifically:

[0042] (1) By setting up a pit array structure on the piston, cylinder liner and cylinder head, the weight of the components is reduced, which can meet the lightweight development needs of the entire machine in the future and reduce fuel consumption;

[0043] (2) By setting up a dimple array structure on the combustion chamber wall, the oil-gas mixing process in the cylinder is changed, which can promote the formation of vortex around the dimple structure, making the oil-gas mixing more uniform, improving the combustion and emission performance of the engine, and meeting the low-carbon and clean development needs of the whole machine in the future;

[0044] (3) This method can evaluate the design of the pit array structure from a theoretical and practical perspective, objectively and systematically, and has reference quantitative data, and has high feasibility and feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The present invention will be further described below in conjunction with the accompanying drawings:

[0046] Figure 1 is a flow chart of the method of the present invention;

[0047] Figure 2 is a flow chart of a method according to an embodiment of the present invention;

[0048] Figure 3 Schematic diagram of the assembly of piston, cylinder liner and cylinder head parts; in the figure: the figure marks are: 1-cylinder head, 2-cylinder head pit, 3-intake hole, 4-exhaust hole, 5-injector hole, 6-cylinder liner, 7-cylinder liner pit, 8-piston, 9-piston pit.

[0049] Figure 4 is a schematic diagram of a piston;

[0050] Figure 5 is a schematic diagram of the cylinder head;

[0051] Figure 6 Schematic diagram of the cylinder liner. DETAILED DESCRIPTION

[0052] The following describes an embodiment of the present invention in detail with reference to the accompanying drawings. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process. However, the protection scope of the present invention is not limited to the following embodiment.

[0053] See also Figure 1 and Figure 2 The flowchart shown below takes the collaborative optimization design of the dimple array structure on the combustion chamber wall of a diesel engine as an example to illustrate the design method. The design method includes the following steps:

[0054] 1) Extract the 3D fluid model of the combustion chamber from the assembled 3D solid model of the engine. The 3D fluid model consists of the piston top surface, cylinder wall, cylinder head, intake duct, exhaust duct, intake valve, exhaust valve, intake inlet, exhaust outlet, etc.

[0055] 2) Carry out bench tests on the engine to obtain the in-cylinder pressure curve, heat release rate curve, and power, economy and emission performance indicators. The power, economy and emission performance indicators tested on the bench mainly include speed, torque and power, fuel consumption rate, oil consumption, CO emissions, NO x Emissions, HC emissions, smoke density, etc.

[0056] 3) Build an engine in-cylinder combustion and emissions simulation model and perform solver settings and calculations. Verify the accuracy of the model using experimental data. The verification criteria are: After the calculations are complete, extract the in-cylinder pressure curve for the final operating cycle and compare it with experimental data under the same operating conditions. The relative error between the simulation and experimental values ​​must be ≤ 5%.

[0057] 4) Conduct temperature field bench tests on the engine's cylinder head, piston, and cylinder liner. Arrange temperature field test measurement points on the actual cylinder head in a circular pattern centered on the nose bridge of the cylinder head's firepower surface. There should be no fewer than four measurement points. Arrange temperature field test measurement points on the actual cylinder liner in a circular pattern centered on the top dead center, bottom dead center, and mid-point of the piston. There should be no fewer than three measurement points. Arrange temperature field test measurement points on the actual piston in a circular pattern centered on the combustion chamber. There should be no fewer than three measurement points.

[0058] 5) Establish a heat transfer simulation model for the key components related to the combustion chamber, including the piston, cylinder liner, and cylinder head, and set up and calculate the solver. In the simulation model, use the third-class thermal boundary to load the convective heat transfer coefficient and surface temperature.

[0059] 6) Verify the accuracy of the heat transfer simulation model of the piston, cylinder liner, and cylinder head through temperature field tests on key components. The verification standard is: the relative error between the simulation value and the test value of the heat transfer simulation model of the piston, cylinder liner, and cylinder head is ≤ 5%.

[0060] 7) Establish a thermal-engine coupling simulation model for the key components related to the combustion chamber, including the piston, cylinder liner, and cylinder head, and set up and calculate the solver. The gas pressure loading values ​​of the piston, cylinder liner, and cylinder head depend on the specific test conditions. The test conditions should include at least one operating point, namely the maximum torque operating point or the calibration operating point.

[0061] 8) Perform parameterized design of the pit array structure on the piston, cylinder liner, and cylinder head to create a sufficiently large design space. Specifically, the pit array structure is arranged on the top surface of the piston combustion chamber, the fire surface of the cylinder head, and the inner wall of the cylinder liner, such as Figure 3As shown. The pit array structure is determined by the position size and shape size of the pit. The position of the pits of the piston and cylinder head is based on the center of the physical structure. The initial pit structure is set at different distances from the center, and the initial pit structure is not less than 2. The shape of the pit is a sphere, cone, cylinder or polygon and any combination of the above. In addition, the center is a designated point, and based on the circular layout, the number of pits is evenly distributed on the circumference, and the number of pits on a single circumference is not less than 4. The schematic diagram of the pits on the piston is shown as follows Figure 4 As shown, the schematic diagram of the pit on the cylinder head is as follows Figure 5 As shown. Furthermore, a pit structure is provided on the actual part of the cylinder liner corresponding to the piston top dead center. The pit shape is a sphere, cone, cylinder or polygon, or any combination thereof. Moreover, the pit structure is on the same horizontal plane and is evenly distributed on the circumference. The number of pits is not less than 4. The schematic diagram of the pits on the cylinder liner is shown as follows. Figure 6 Furthermore, the arrangement of the pit structure should be on at least one physical object.

[0062] 9) For each sample point in the design space, extract a three-dimensional fluid model according to step (1) and establish an engine in-cylinder combustion and emission simulation model. Set up and calculate the solver, and extract the characteristic parameters representing the combustion performance and emission performance of each sample point. The characteristic parameters representing the combustion performance and emission performance that are directly extracted or indirectly calculated through the simulation model should include the in-cylinder pressure curve, in-cylinder heat release rate curve, in-cylinder average temperature curve, in-cylinder average turbulent kinetic energy curve, indicated fuel consumption, indicated thermal efficiency, CO emissions, NOx emissions, HC emissions, smoke density, etc.

[0063] 10) Further, for each sample point in the design space, a heat transfer simulation model and a thermo-mechanical coupling simulation model of the key components related to the combustion chamber, the piston, cylinder liner, and cylinder head, are established according to step (5), and the solver is set and calculated. The characteristic parameters representing the heat transfer characteristics and reliability performance of each sample point are extracted. The characteristic parameters representing the heat transfer characteristics and reliability performance directly extracted or indirectly calculated by the simulation model should include the maximum temperature, maximum thermal stress, maximum thermo-mechanical coupling stress, minimum safety factor, etc.

[0064] 11) Establish a collaborative optimization mathematical model for the dimple array structural design, obtain the optimal solution set, and select at least three representative solutions. The objective function in the collaborative optimization mathematical model should include indicated thermal efficiency, maximum thermal stress, and minimum safety factor.

[0065] 12) The key components of the typical solution, piston, cylinder liner and cylinder head, are processed using 3D printing technology.

[0066] 13) Install the newly designed key components and repeat the tests in steps 2) and 4).

[0067] 14) Obtain the optimal pit array structure design scheme through experimental data comparison.

Claims

1. A method for designing a combustion chamber wall pit array structure, characterized in that: The steps include: Step 1: extracting a three-dimensional fluid model of the combustion chamber from the assembled three-dimensional solid model of the engine; Step 2: Perform a bench test on the engine to obtain the in-cylinder pressure curve, heat release rate curve, and power, economy, and emission performance indicators; Step 3: Establish an engine cylinder combustion and emission simulation model and perform solver settings and calculations; verify the accuracy of the engine cylinder combustion and emission simulation model through experimental data obtained; Step 4: Perform a temperature field bench test on the cylinder head, piston, and cylinder liner of the engine; Step 5: Establish a heat transfer simulation model of the piston, cylinder liner, and cylinder head related to the combustion chamber and perform solver settings and calculations; Step 6: Verify the accuracy of the heat transfer simulation model of the piston, cylinder liner and cylinder head through temperature field tests of the piston, cylinder liner and cylinder head; Step 7: Establish a thermal-engine coupling simulation model of the piston, cylinder liner, and cylinder head related to the combustion chamber and perform solver settings and calculations; Step 8: Construct a design space and perform parametric design of the pit array structure on the piston, cylinder liner, and cylinder head; Step 9: For each sample point in the design space, extract a three-dimensional fluid model according to step 1, establish an engine in-cylinder combustion and emission simulation model, set up and calculate the solver, and extract characteristic parameters representing the combustion performance and emission performance of each sample point; Step 10: Further establish a heat transfer simulation model and a thermal-mechanical coupling simulation model of the piston, cylinder liner, and cylinder head related to the combustion chamber for each sample point in the design space according to step 5, set up and calculate the solver, and extract characteristic parameters representing the heat transfer characteristics and reliability performance of each sample point; Step 11, establishing a collaborative optimization mathematical model for the dimple array structure design to obtain an optimal solution set; Step 12: Process the piston, cylinder liner and cylinder head in the typical solution; Step 13: Install the newly designed piston, cylinder liner, and cylinder head and repeat the test of steps 3 and 4; Step 14: Obtain the best design scheme of the pit array structure by comparing the experimental data.

2. The design method according to claim 1, wherein: In step 1, the three-dimensional fluid model includes the piston top surface, cylinder wall, cylinder head, intake duct, exhaust duct, intake valve, exhaust valve, intake inlet and exhaust outlet; In step 2, the power, economy and emission performance indicators include speed, torque and power, fuel consumption rate, oil consumption, CO emissions, NO x Emissions, HC emissions and smoke; In step 3, verifying the accuracy of the engine cylinder combustion and emission simulation model includes: The in-cylinder pressure curve of the last working cycle was extracted and compared with the test data under the same working conditions. The verification standard was: the relative error between the simulation value and the test value was ≤ 5%.

3. The design method according to claim 1, wherein: Also included in step 4: Arrange the temperature field test measurement points on the cylinder head. The measurement points should be distributed in a circular pattern with the center of the nose bridge area on the cylinder head fire surface. There should be more than 4 measurement points. Arrange temperature field test measuring points on the cylinder liner. The measuring points should include the positions of the piston at the top dead center, bottom dead center, and mid-point of operation. There should be more than 3 measuring points. Arrange the temperature field test measuring points on the actual piston. The measuring points should be distributed in a circle with the center of the combustion chamber, and there should be more than 3 measuring points.

4. The design method according to claim 1, wherein: In step 5, the heat transfer simulation model of the piston, cylinder liner and cylinder head adopts the third type of thermal boundary loading convection heat transfer coefficient and surface temperature; In step 6, the verification criteria are: the relative error between the simulation value and the test value is ≤ 5%; In step 7, the gas pressure loading values ​​of the piston, cylinder liner and cylinder head depend on specific test conditions, which include a maximum torque operating point or a calibration operating point.

5. The design method according to claim 1, wherein: In step 8, it also includes: A pit array structure is arranged on the top surface of the piston combustion chamber, the fire surface of the cylinder head, and the inner wall of the cylinder liner, and the pit array structure is determined by the position, size, shape and size of the pits. The position of the pits in the piston and cylinder head is based on the center of the physical structure. The initial pit structure is set at different distances from the center of the physical structure. The number of initial pit structures is two or more. The shape of the pit is sphere, cone and / or cylinder or polygon; Taking the center of the physical structure as the designated point, based on a circular layout, a number of pits are evenly distributed on the circumference, and the number of pits on a single circumference is more than 4.

6. The design method according to claim 5, wherein: A pit structure is provided on the physical part of the cylinder sleeve corresponding to the top dead center of the piston. The pit structures are located in the same horizontal plane and are evenly distributed on the circumference. The pit structure is arranged on at least one physical object.

7. The design method according to claim 1, wherein: In step 9, characteristic parameters characterizing combustion performance and emission performance are directly extracted or indirectly calculated through the simulation model, including the in-cylinder pressure curve, the in-cylinder heat release rate curve, the in-cylinder average temperature curve, the in-cylinder average turbulent kinetic energy curve, the indicated fuel consumption, the indicated thermal efficiency, CO emissions, NOx emissions, HC emissions and smoke density.

8. The design method according to claim 1, wherein: In step 10, characteristic parameters characterizing heat transfer characteristics and reliability performance are directly extracted or indirectly calculated through the simulation model, including maximum temperature, maximum thermal stress, maximum thermal-mechanical coupling stress, and minimum safety factor.

9. The design method according to any one of claims 1 to 8, characterized in that: In step 11, the objective functions in the collaborative optimization mathematical model of the dimple array structure design include indicated thermal efficiency, maximum thermal stress, and minimum safety factor.

10. A combustion chamber obtained by the combustion chamber wall surface pit array structure design method according to any one of claims 1 to 9.

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