A minimalist mechanism generation method based on entropy constant correction

Abstract

The present invention discloses a minimalist mechanism generation method based on entropy constant correction, belonging to the technical field of chemical reaction kinetics, including: S1. Construct a single-step reaction formula when the fuel burns sufficiently, and then determine the species participating in the reaction; S2. Determine the standard NASA7 coefficients of the species participating in the reaction and find the entropy constant to be optimized; S3. For all species participating in the reaction, use their current entropy constant as the initial value, and optimize the entropy constant with the goal of minimizing the relative error of the combustion equilibrium temperature between the minimalist mechanism and the detailed mechanism within the set state range; S4. Generate a minimalist mechanism based on the optimized entropy constant. Compared with general minimalist mechanisms, the simplified mechanism generated by the present invention uses fewer components and reactions, and has significantly lower computational costs; by modifying the entropy constant of each species to change the chemical equilibrium of the reaction, it can better fit the combustion equilibrium temperature of the detailed mechanism.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical reaction kinetics, and particularly relates to a minimalist mechanism generation method based on entropy constant correction. Background Art

[0002] With the continuous improvement of the performance requirements of aerospace engines, the numerical simulation technology of the combustion and flow processes in the combustion chamber has become a key research direction. When carrying out such numerical simulations, the selection of the fuel chemical reaction mechanism directly affects the calculation cost, efficiency, and accuracy. Currently, the commonly used reaction mechanisms mainly include detailed mechanisms, skeletal mechanisms, reduced mechanisms, and lumped mechanisms. Among them, the detailed mechanism includes fuels, oxidants (usually oxygen), and a large number of intermediate components and elementary reactions. Although it can accurately describe the combustion process, due to the large number of components, the calculation amount increases significantly (usually proportional to the number of components and inversely proportional to the available time step), resulting in low calculation efficiency. The skeletal mechanism reduces the number of components by eliminating elementary reactions and intermediate components that have little influence on the overall combustion process based on the detailed mechanism, thereby reducing the calculation amount while maintaining high accuracy. The reduced mechanism is a further optimization of the skeletal mechanism. For a specific operating condition range (such as a specific temperature, pressure, or equivalence ratio range), non-critical reaction paths and components are combined or deleted to make the mechanism more compact and the calculation efficiency higher, but the applicable range is relatively limited. The lumped mechanism only retains a few key components and approximately describes the combustion process using global reactions (such as single-step or multi-step reactions). Its calculation efficiency is the highest, but due to excessive simplification, the prediction accuracy is low, especially with large errors under complex combustion conditions. Table 1 shows the main characteristics of the above four types of mechanisms:

[0003] Table 1: Main Characteristics of Four Types of Mechanisms

[0004]

[0005] The reaction mechanism for ideal numerical simulation should strike a balance between computational efficiency and prediction accuracy to meet the requirements of engineering practice. In computational fluid dynamics (CFD) simulations, the most widely used in practical applications is the simplified reaction mechanism. However, it is difficult for such mechanisms to be consistent with the calculation results of the detailed mechanism over a wide range of temperatures and pressures, especially at low temperatures and low pressures, where the deviation is more significant. Since it is extremely difficult to make the simplified mechanism completely consistent with the detailed mechanism in all combustion characteristics (such as ignition delay, equilibrium temperature, etc.), in applications where only the steady-state outlet gas components of the combustion device are concerned (such as engine overall performance evaluation where strict requirements for combustion details are not imposed), some studies adopt the lumped mechanism. Such mechanisms usually only include fuel, oxygen, nitrogen, and complete combustion products (such as carbon dioxide and water), and their form is extremely simplified. However, the lumped mechanism has inherent defects: if the irreversible reaction form is adopted, all fuels are forced to be completely oxidized, resulting in a significantly higher heat release than the actual situation; if the reversible reaction form is adopted, due to equilibrium limitations, a large amount of fuel is not oxidized, and the heat release is much lower than the true value. This significant deviation from the detailed mechanism makes it difficult for the lumped mechanism to accurately evaluate the overall performance indicators of the engine.

[0006] In view of the above problems, in current engineering practice, in order to ensure the reliability of combustion performance evaluation, simplified mechanisms with a larger number of components and reactions are still generally adopted. However, this method significantly increases the computational load, resulting in an extended design iteration cycle and restricting the improvement of engine R & D efficiency. Therefore, developing a new reaction mechanism that can both maintain computational efficiency and accurately predict combustion characteristics over a wide range of operating conditions is of great significance for promoting engine design optimization. Summary of the Invention

[0007] Aiming at the above deficiencies in the prior art, the minimalist mechanism generation method based on entropy constant correction provided by the present invention solves the problems that the existing simplified mechanism generation methods have a large computational load, a long design iteration cycle, and thus restrict the engine R & D efficiency.

[0008] To achieve the above invention objective, the technical solution adopted by the present invention is: a minimalist mechanism generation method based on entropy constant correction, including the following steps:

[0009] S1. Construct a single-step reaction equation when the fuel is fully burned, and then determine the species participating in the reaction;

[0010] S2. Determine the standard NASA7 coefficients of the species participating in the reaction, and find the entropy constant to be optimized;

[0011] S3. For all species participating in the reaction, using their current entropy constant as the initial value, with the goal of minimizing the relative error of the combustion equilibrium temperature between the minimalist mechanism and the detailed mechanism within the set state range, optimize the entropy constant;

[0012] S4. Generate a minimalist mechanism based on the optimized entropy constant.

[0013] Further, the step S1 is specifically as follows:

[0014] Calculate the stoichiometric number of oxygen required for complete combustion according to the numbers of carbon atoms, hydrogen atoms, and oxygen atoms in the fuel used.

[0015] Construct a single-step reaction formula for the fuel used based on the stoichiometric number of oxygen, and determine the species participating in the reaction.

[0016] Further, in the step S2, among the standard NASA7 coefficients of the species participating in the reaction, the 7th and 14th parameters are used as the entropy constants to be optimized.

[0017] Further, the step S3 includes the following sub-steps:

[0018] S31. Form a corresponding minimalist mechanism according to the entropy constant of each species participating in the reaction.

[0019] S32. Calculate the combustion equilibrium temperatures corresponding to the minimalist mechanism and the detailed mechanism at different states within the set state range.

[0020] S33. Compare the combustion equilibrium temperatures corresponding to the minimalist mechanism and the detailed mechanism to obtain the relative error of the combustion equilibrium temperature at different states, and take the maximum value as the relative error of the combustion equilibrium temperature between the minimalist mechanism and the detailed mechanism within the set state range.

[0021] S34. Adjust the entropy constant values of the species participating in the reaction, and use the optimization algorithm to optimize the relative error of the combustion equilibrium temperature with different combinations of entropy constant values as the input, and determine the combination of entropy constants corresponding to the minimum relative error of the combustion equilibrium temperature within the set state range as the entropy constant optimization result.

[0022] Further, the set state range includes a pressure range of 0.5 - 10 atm, a temperature range of 1000 - 2000 K, and an equivalence ratio range of 0.5 - 2.0.

[0023] Further, in the step S33, when adjusting the entropy constant values of the species participating in the reaction, at the same state, for the same species, the change amount of its corresponding two entropy constant values is the same.

[0024] Further, the step S34 includes the following sub-steps:

[0025] S34-1. Initialize and generate different combinations of entropy constant values as several points for the optimization algorithm.

[0026] S34-2. Sort several current points according to the values of the objective function, and determine the worst point, the second-worst point, and the best point among them; where the objective function is the relative error of the combustion equilibrium temperature corresponding to different points.

[0027] S34-3. Calculate the center point of other points except the worst point.

[0028] S34-4. Calculate the reflection point according to the calculated center point.

[0029] When the relative error of the combustion equilibrium temperature corresponding to the reflection point is less than the relative error of the combustion equilibrium temperature corresponding to the best point, calculate the expansion point, and determine whether the relative error of the combustion equilibrium temperature corresponding to the expansion point is less than the relative error of the combustion equilibrium temperature corresponding to the reflection point; if so, replace the current worst point with the expansion point, and return to step S34-2; if not, replace the current worst point with the reflection point, and return to step S34-2.

[0030] When the relative error of the combustion equilibrium temperature corresponding to the reflection point is less than the relative error of the combustion equilibrium temperature corresponding to the second-worst point and greater than or equal to the relative error of the combustion equilibrium temperature corresponding to the best point, replace the current worst point with the reflection point, and return to step S34-2.

[0031] When the relative error of the combustion equilibrium temperature corresponding to the reflection point is greater than or equal to the relative error of the combustion equilibrium temperature corresponding to the second-worst point and less than the relative error of the combustion equilibrium temperature corresponding to the worst point, calculate the outward contraction point, and determine whether the relative error of the combustion equilibrium temperature corresponding to the outward contraction point is less than the relative error of the combustion equilibrium temperature corresponding to the reflection point; if so, replace the current worst point with the outward contraction point, and return to step S34-2; if not, replace all points except the best point, and return to step S34-2.

[0032] When the relative error of the combustion equilibrium temperature corresponding to the reflection point is greater than or equal to the relative error of the combustion equilibrium temperature corresponding to the worst point, calculate the inward contraction point, and determine whether the relative error of the combustion equilibrium temperature corresponding to the inward contraction point is less than the relative error of the combustion equilibrium temperature corresponding to the worst point; if so, replace the current worst point with the inward contraction point, and return to step S34-2; if not, replace all points except the best point, and return to step S34-2.

[0033] S34-5. Repeat steps S34-2 to S34-4 until the cut-off condition is met, and take the entropy constant combination corresponding to the best point with the minimum relative error of the combustion equilibrium temperature as the entropy constant optimization result; where the cut-off condition is to reach the set number of iterations or the minimum relative error of the combustion equilibrium temperature is less than or equal to the set error threshold.

[0034] Further, the reflection point is , and the expansion point is , the outward contraction point is , the inward contraction point is , the replaced point is ;

[0035] In the formula, represents the calculated center point, represents the current worst point, represents the current best point, represents the point before replacement, represents the reflection coefficient, represents the expansion coefficient, represents the contraction coefficient, represents the back-off coefficient.

[0036] The beneficial effects of the present invention are as follows:

[0037] (1) During the engine R & D process, compared with the general simplified mechanism, the simplified mechanism generated by applying the method of the present invention uses fewer combinations and reactions. In CFD calculations, the calculation cost of the flow term is positively correlated with the number of components, and in combustion term calculations, the calculation cost is positively correlated with the number of components and reactions. Therefore, this method has significantly lower calculation costs and can effectively improve the R & D efficiency of the engine.

[0038] (2) During the numerical simulation of the engine combustion chamber and the flow process, compared with the existing overall mechanism, the simplified mechanism generated by using the method of the present invention, by modifying the entropy constants of each species to change the reaction chemical equilibrium, avoids the defect in common overall mechanisms that due to irreversible reactions, the combustion products are completely generated and the heat release is too high, resulting in a significantly higher equilibrium temperature. It can better fit the combustion equilibrium temperature of the detailed mechanism, which is also unique to the method of the present invention compared with the existing overall mechanisms. Description of the Drawings

[0039] Figure 1 is the flow chart of the minimalist mechanism generation method based on entropy constant correction provided by the present invention.

[0040] Figure 2 is the relative error distribution diagram of the original mechanism equilibrium temperature when the ratio is 1 in the present invention.

[0041] Figure 3 is the relative error distribution diagram of the mechanism equilibrium temperature after entropy constant optimization when the ratio is 1 in the present invention. Detailed Embodiments

[0042] The specific embodiments of the present invention will be described below to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0043] The basic idea of the present invention is based on the reversible minimalist mechanism reaction formula, with the optimization goal of the combustion equilibrium temperature of the detailed mechanism in a wide range. The entropy constants of each species in the reaction are optimized within a large range without constraints, so that the combustion equilibrium temperature of the minimalist mechanism fits as closely as possible to that of the similar mechanism within a wide range.

[0044] An embodiment of the present invention provides a minimalist mechanism generation method based on entropy constant correction, as Figure 1 shown, including the following steps:

[0045] S1. Construct a single-step reaction formula when the fuel burns sufficiently, and then determine the species participating in the reaction;

[0046] S2. Determine the standard NASA7 coefficients of the species participating in the reaction and find the entropy constants to be optimized;

[0047] S3. For all species participating in the reaction, use their current entropy constants as the initial values, and optimize the entropy constants with the goal of minimizing the relative error of the combustion equilibrium temperature between the minimalist mechanism and the detailed mechanism within the set state range;

[0048] S4. Generate a minimalist mechanism based on the optimized entropy constants.

[0049] In the present invention, the chemical reaction process of the fuel combustion process in the engine combustion chamber can be described by the following ordinary differential equations:

[0050]

[0051] In the formula, represents the mass of the i-th component, represents the generation rate of the i-th component corresponding to the chemical reaction, which is expressed as:

[0052]

[0053] In the formula, represents the number of reactions, represents the number of components, represents the molar mass of the i-th component, represents the change in the stoichiometric number of the i-th component in the r-th reaction, represents the forward reaction rate constant of the r-th reaction, represents the reverse reaction rate constant of the r-th reaction, represents the molar concentration of the j-th component, with the superscript being the forward reaction concentration exponent of the j-th component in the r-th reaction, with the superscript representing the reverse reaction concentration exponent of the j-th component in the r-th reaction.

[0054] Generally, each chemical reaction equation has three parameters to describe the calculation process of the forward reaction rate of this reaction equation, that is, the pre-exponential factor in the Arrhenius equation, the temperature exponent and the activation energy , which is expressed as:

[0055]

[0056] Common elementary reaction equations are all reversible reactions. For reversible reactions, the reverse reaction rate is generally calculated through the reaction equilibrium constant as follows:

[0057]

[0058]

[0059] In the formula, represents atmospheric pressure, represents the gas constant, represents temperature, represents the stoichiometric coefficient of the reactant of the -th species in the reaction, represents the stoichiometric coefficient of the product of the -th species in the reaction, represents the gas constant of the -th species (for common ideal gases, , where is the molar mass), represents the standard enthalpy of the -th species, represents the standard entropy of the -th species.

[0060] In the overall mechanism or simplified mechanism, since multiple elementary reactions are integrated, irreversible reactions will appear. At this time, there is no reaction equilibrium and no reaction equilibrium constant , and the reverse reaction rate .

[0061] For most global reaction mechanisms, the main reaction appears as an irreversible reaction, which means that when the fuel is below the stoichiometric ratio corresponding to the oxidizer, all the fuel will be completely burned, and the total heat release of the global mechanism is much higher than that of the detailed reaction mechanism; on the other hand, if the main reaction of the global mechanism is a reversible reaction, the chemical reaction equilibrium position is limited by the form of the reaction equation itself, resulting in a much lower total heat release than that of the detailed mechanism.

[0062] Although the Arrhenius parameters (pre-exponential factor , temperature exponent and activation energy ) have determined the basic characteristics of the reaction rate through the reaction equation, there are still several key thermodynamic parameters that need to be further optimized, especially the standard molar entropy s and the standard enthalpy of formation h. These parameters have a decisive influence on the reaction equilibrium position and heat release characteristics.

[0063] The NASA seven-coefficient polynomial parameterization method is widely used to calculate the thermodynamic properties of chemical species, such as specific heat capacity , enthalpy and entropy , and its specific calculation is as follows:

[0064]

[0065]

[0066]

[0067] This method describes these properties within a certain temperature range through a set of coefficients . Among them, the entropy constant only affects the entropy and does not change the values of enthalpy and specific heat capacity. By precisely adjusting the entropy constant, fine-tuning of the entropy value can be achieved, thereby changing the equilibrium temperature of the reaction system without affecting other thermodynamic properties.

[0068] Therefore, the present invention precisely regulates the chemical reaction equilibrium state by optimizing and adjusting the entropy constants ( ) of each species in the reaction, without affecting the specific heat capacity and enthalpy, and then changes the Gibbs free energy of the reaction system, ultimately achieving the purpose of modifying the reaction equilibrium temperature.

[0069] Specifically, step S1 of the embodiment of the present invention is specifically as follows:

[0070] According to the numbers of carbon atoms, hydrogen atoms, and oxygen atoms in the fuel used in the numerical simulation of the combustion and flow process in the engine combustion chamber, calculate the oxygen stoichiometric number required for complete combustion;

[0071] Construct a single-step reaction equation using the fuel according to the oxygen stoichiometric number and determine the species participating in the reaction.

[0072] In a specific example of this embodiment, according to the number of carbon atoms a, hydrogen atoms b, and oxygen atoms c in the fuel, the required oxygen stoichiometric number is calculated as a + b / 4 - c / 2, thereby obtaining the fully combusted products CO2 and H2O. The following are examples: For hydrogen fuel H2, a = 0, b = 2, c = 0, then the single-step reaction is H2 + 0.5O2 <=> H2O; for methane fuel CH4, a = 1, b = 4, c = 0, then the single-step reaction is CH4 + 2O2 <=> CO2 + 2H2O; for ethanol fuel C2H6O, a = 2, b = 6, c = 1, then the single-step reaction is C2H6O + 3O2 <=> 2CO2 + 3H2O.

[0073] In step S2 of the embodiment of the present invention, among the standard NASA7 coefficients of the species participating in the reaction, the 7th and 14th parameters are used as the entropy constants to be optimized.

[0074] In a specific example of this embodiment, for common species, their standard NASA7 coefficients are as follows:

[0075] The standard NASA coefficients of O are successively 2.56942078E+00, -8.59741137E-05, 4.19484589E-08, -1.00177799E-11, 1.22833691E-15, 2.92175791E+04, 4.78433864E+00, 3.16826710E+00, -3.27931884E-03, 6.64306396E-06, -6.12806624E-09, 2.11265971E-12, 2.91222592E+04, 2.05193346E+00;

[0076] The standard NASA coefficients of O2 are successively 3.28253784E+00, 1.48308754E-03, -7.57966669E-07, 2.09470555E-10, -2.16717794E-14, -1.08845772E+03, 5.45323129E+00, 3.78245636E+00, -2.99673416E-03, 9.84730201E-06, -9.68129509E-09, 3.24372837E-12, -1.06394356E+03, 3.65767573E+00;

[0077] The standard NASA coefficients of H are 2.50000001E+00, -2.30842973E-11, 1.61561948E-14, -4.73515235E-18, 4.98197357E-22, 2.54736599E+04, -4.46682914E-01, 2.50000000E+00, 7.05332819E-13, -1.99591964E-15, 2.30081632E-18, -9.27732332E-22, 2.54736599E+04, -4.46682853E-01 in sequence;

[0078] The standard NASA coefficients of H2 are 3.33727920E+00, -4.94024731E-05, 4.99456778E-07, -1.79566394E-10, 2.00255376E-14, -9.50158922E+02, -3.20502331E+00, 2.34433112E+00, 7.98052075E-03, -1.94781510E-05, 2.01572094E-08, -7.37611761E-12, -9.17935173E+02, 6.83010238E-01 in sequence;

[0079] The standard NASA coefficients of OH are 3.09288767E+00, 5.48429716E-04, 1.26505228E-07, -8.79461556E-11, 1.17412376E-14, 3.85865700E+0, 4.47669610E+00, 3.99201543E+00, -2.40131752E-03, 4.61793841E-06, -3.88113333E-09, 1.36411470E-12, 4.61508056E+03, -1.03925458E-01 in sequence;

[0080] The standard NASA coefficients of H2O are 3.03399249E+00, 2.17691804E-03, -1.64072518E-07, -9.70419870E-11, 1.68200992E-14, -3.00042971E+04, 4.96677010E+00, 4.19864056E+00, -2.03643410E-03, 6.52040211E-06, -5.48797062E-09, 1.77197817E-12, -3.02937267E+04, -8.49032208E-01 in sequence;

[0081] The standard NASA coefficients of HO2 are 4.01721090E+00, 2.23982013E-03, -6.33658150E-07, 1.14246370E-10, -1.07908535E-14, 1.11856713E+02, 3.78510215E+00, 4.30179801E+00, -4.74912051E-03, 2.11582891E-05, -2.42763894E-08, 9.29225124E-12, 2.94808040E+02, 3.71666245E+00 in sequence;

[0082] The standard NASA coefficients of H2O2 are 4.16500285E+00, 4.90831694E-03, -1.90139225E-06, 3.71185986E-10, -2.87908305E-14, -1.78617877E+04, 2.91615662E+00, 4.27611269E+00, -5.42822417E-04, 1.67335701E-05, -2.15770813E-08, 8.62454363E-12, -1.77025821E+04, 3.43505074E+00 in sequence;

[0083] The standard NASA coefficients of C are 2.49266888E+00, 4.79889284E-05, -7.24335020E-08, 3.74291029E-11, -4.87277893E-15, 8.54512953E+04, 4.80150373E+00, 2.55423955E+00, -3.21537724E-04, 7.33792245E-07, -7.32234889E-10, 2.66521446E-13, 8.54438832E+04, 4.53130848E+00 in sequence;

[0084] The standard NASA coefficients of CH are 2.87846473E+00, 9.70913681E-04, 1.44445655E-07, -1.30687849E-10, 1.76079383E-14, 7.10124364E+04, 5.48497999E+00, 3.48981665E+00, 3.23835541E-04, -1.68899065E-06, 3.16217327E-09, -1.40609067E-12, 7.07972934E+04, 2.08401108E+00 in sequence;

[0085] The standard NASA coefficients of CH2 are 2.87410113E+00, 3.65639292E-03, -1.40894597E-06, 2.60179549E-10, -1.87727567E-14, 4.62636040E+04, 6.17119324E+00, 3.76267867E+00, 9.68872143E-04, 2.79489841E-06 -3.85091153E-09, 1.68741719E-12, 4.60040401E+04, 1.56253185E+00 in sequence;

[0086] The standard NASA coefficients of CH2(S) are 2.29203842E+00, 4.65588637E-03, -2.01191947E-06, 4.17906000E-10, -3.39716365E-14, 5.09259997E+04, 8.62650169E+00, 4.19860411E+00, -2.36661419E-03, 8.23296220E-06, -6.68815981E-09, 1.94314737E-12, 5.04968163E+04, -7.69118967E-01 in sequence;

[0087] The standard NASA coefficients of CH3 are 2.28571772E+00, 7.23990037E-03, -2.98714348E-06, 5.95684644E-10, -4.67154394E-14, 1.67755843E+04, 8.48007179E+00, 3.67359040E+00, 2.01095175E-03, 5.73021856E-06, -6.87117425E-09, 2.54385734E-12, 1.64449988E+04, 1.60456433E+00 in sequence;

[0088] The standard NASA coefficients of CH4 are 7.48514950E-02, 1.33909467E-02, -5.73285809E-06, 1.22292535E-09, -1.01815230E-13, -9.46834459E+03, 1.84373180E+01, 5.14987613E+00, -1.36709788E-02, 4.91800599E-05, -4.84743026E-08, 1.66693956E-11, -1.02466476E+04, -4.64130376E+00 in sequence;

[0089] The standard NASA coefficients of CO are 2.71518561E+00, 2.06252743E-03, -9.98825771E-07, 2.30053008E-10, -2.03647716E-14, -1.41518724E+04, 7.81868772E+00, 3.57953347E+00, -6.10353680E-04, 1.01681433E-06, 9.07005884E-10, -9.04424499E-13, -1.43440860E+04, 3.50840928E+00 in sequence;

[0090] The standard NASA coefficients of CO2 are 3.85746029E+00, 4.41437026E-03, -2.21481404E-06, 5.23490188E-10, -4.72084164E-14, -4.87591660E+04, 2.27163806E+00, 2.35677352E+00, 8.98459677E-03, -7.12356269E-06, 2.45919022E-09, -1.43699548E-13, -4.83719697E+04, 9.90105222E+00 in sequence;

[0091] The standard NASA coefficients of HCO are 2.77217438E+00, 4.95695526E-03, -2.48445613E-06, 5.89161778E-10, -5.33508711E-14, 4.01191815E+03, 9.79834492E+00, 4.22118584E+00, -3.24392532E-03, 1.37799446E-05, -1.33144093E-08, 4.33768865E-12, 3.83956496E+03, 3.39437243E+00 in sequence;

[0092] The standard NASA coefficients of CH2O are 1.76069008E+00, 9.20000082E-03, -4.42258813E-06, 1.00641212E-09, -8.83855640E-14, -1.39958323E+04, 1.36563230E+01, 4.79372315E+00, -9.90833369E-03, 3.73220008E-05, -3.79285261E-08, 1.31772652E-11, -1.43089567E+04, 6.02812900E-01 in sequence;

[0093] The standard NASA coefficients of CH2OH are 3.69266569E+00, 8.64576797E-03, -3.75101120E-06, 7.87234636E-10, -6.48554201E-14, -3.24250627E+03, 5.81043215E+00, 3.86388918E+00, 5.59672304E-03, 5.93271791E-06, -1.04532012E-08, 4.36967278E-12, -3.19391367E+03, 5.47302243E+00 in sequence;

[0094] The standard NASA coefficients of CH3O are 0.03770799E+02, 0.07871497E-01, -0.02656384E-04, 0.03944431E-08, -0.02112616E-12, 0.12783252E+03, 0.02929575E+02, 0.02106204E+02, 0.07216595E-01, 0.05338472E-04, -0.07377636E-07, 0.02075610E-10, 0.09786011E+04, 0.13152177E+02 in sequence;

[0095] The standard NASA coefficients of CH3OH are 1.78970791E+00, 1.40938292E-02, -6.36500835E-06, 1.38171085E-09, -1.17060220E-13, -2.53748747E+04, 1.45023623E+01, 5.71539582E+00, -1.52309129E-02, 6.52441155E-05, -7.10806889E-08, 2.61352698E-11, -2.56427656E+04, -1.50409823E+00 in sequence;

[0096] The standard NASA coefficients of C2H are 3.16780652E+00, 4.75221902E-03, -1.83787077E-06, 3.04190252E-10, -1.77232770E-14, 6.71210650E+04, 6.63589475E+00, 2.88965733E+00, 1.34099611E-02, -2.84769501E-05, 2.94791045E-08, -1.09331511E-11, 6.68393932E+04, 6.22296438E+00 in sequence;

[0097] The standard NASA coefficients of C2H2 are 4.14756964E+00, 5.96166664E-03, -2.37294852E-06, 4.67412171E-10, -3.61235213E-14, 2.59359992E+04, -1.23028121E+00, 8.08681094E-01, 2.33615629E-02, -3.55171815E-05, 2.80152437E-08, -8.50072974E-12, 2.64289807E+04, 1.39397051E+01 in sequence;

[0098] The standard NASA coefficients of C2H3 are 3.01672400E+00, 1.03302292E-02, -4.68082349E-06, 1.01763288E-09, -8.62607041E-14, 3.46128739E+04, 7.78732378E+00, 3.21246645E+00, 1.51479162E-03, 2.59209412E-05, -3.57657847E-08, 1.47150873E-11, 3.48598468E+04, 8.51054025E+00 in sequence;

[0099] The standard NASA coefficients of C2H4 are 2.03611116E+00, 1.46454151E-02, -6.71077915E-06, 1.47222923E-09, -1.25706061E-13, 4.93988614E+03, 1.03053693E+01, 3.95920148E+00, -7.57052247E-03, 5.70990292E-05, -6.91588753E-08, 2.69884373E-11, 5.08977593E+03, 4.09733096E+00 in sequence;

[0100] The standard NASA coefficients of C2H5 are 1.95465642E+00, 1.73972722E-02, -7.98206668E-06, 1.75217689E-09, -1.49641576E-13, 1.28575200E+04, 1.34624343E+01, 4.30646568E+00, -4.18658892E-03, 4.97142807E-05, -5.99126606E-08, 2.30509004E-11, 1.28416265E+04, 4.70720924E+00 in sequence;

[0101] The standard NASA coefficients of C2H6 are 1.07188150E+00, 2.16852677E-02, -1.00256067E-05, 2.21412001E-09, -1.90002890E-13, -1.14263932E+04, 1.51156107E+01, 4.29142492E+00, -5.50154270E-03, 5.99438288E-05, -7.08466285E-08, 2.68685771E-11, -1.15222055E+04, 2.66682316E+00 in sequence;

[0102] The standard NASA coefficients of CH2CO are 4.51129732E+00, 9.00359745E-03, -4.16939635E-06, 9.23345882E-10, -7.94838201E-14, -7.55105311E+03, 6.32247205E-01, 2.13583630E+00, 1.81188721E-02, -1.73947474E-05, 9.34397568E-09, -2.01457615E-12, -7.04291804E+03, 1.22156480E+01 in sequence;

[0103] The standard NASA coefficients of HCCO are 0.56282058E+01, 0.40853401E-02, -0.15934547E-05, 0.28626052E-09, -0.19407832E-13, 0.19327215E+05, -0.39302595E+01, 0.22517214E+01, 0.17655021E-01, -0.23729101E-04, 0.17275759E-07, -0.50664811E-11, 0.20059449E+05, 0.12490417E+02 in sequence;

[0104] The standard NASA coefficients of HCCOH are 0.59238291E+01, 0.67923600E-02, -0.25658564E-05, 0.44987841E-09, -0.29940101E-13, 0.72646260E+04, -0.76017742E+01, 0.12423733E+01, 0.31072201E-01, -0.50866864E-04, 0.43137131E-07, -0.14014594E-10, 0.80316143E+04, 0.13874319E+02 in sequence;

[0105] The standard NASA coefficients of H2CN are 0.52097030E+01, 0.29692911E-02, -0.28555891E-06, -0.16355500E-09, 0.30432589E-13, 0.27677109E+05, -0.44444780E+01, 0.28516610E+01, 0.56952331E-02, 0.10711400E-05, -0.16226120E-08, -0.23511081E-12, 0.28637820E+05, 0.89927511E+01 in sequence;

[0106] The standard NASA coefficients of HCN are 0.38022392E+01, 0.31464228E-02, -0.10632185E-05, 0.16619757E-09, -0.97997570E-14, 0.14407292E+05, 0.15754601E+01, 0.22589886E+01, 0.10051170E-01, -0.13351763E-04, 0.10092349E-07, -0.30089028E-11, 0.14712633E+05, 0.89164419E+01 in sequence;

[0107] The standard NASA coefficients of HNO are 0.29792509E+01, 0.34944059E-02, -0.78549778E-06, 0.57479594E-10, -0.19335916E-15, 0.11750582E+05, 0.86063728E+01, 0.45334916E+01, -0.56696171E-02, 0.18473207E-04, -0.17137094E-07, 0.55454573E-11, 0.11548297E+05, 0.17498417E+01 in sequence;

[0108] The standard NASA coefficients of N are 0.24159429E+01, 0.17489065E-03, -0.11902369E-06, 0.30226245E-10, -0.20360982E-14, 0.56133773E+05, 0.46496096E+01, 0.25000000E+01, 0.00000000E+00, 0.00000000E+00, 0.00000000E+00, 0.00000000E+00, 0.56104637E+05, 0.41939087E+01 in sequence;

[0109] The standard NASA coefficients of NNH are 0.37667544E+01, 0.28915082E-02, -0.10416620E-05, 0.16842594E-09, -0.10091896E-13, 0.28650697E+05, 0.44705067E+01, 0.43446927E+01, -0.48497072E-02, 0.20059459E-04, -0.21726464E-07, 0.79469539E-11, 0.28791973E+05, 0.29779410E+01 in sequence;

[0110] The standard NASA coefficients of N2O are 0.48230729E+01, 0.26270251E-02, -0.95850874E-06, 0.16000712E-09, -0.97752303E-14, 0.80734048E+04, -0.22017207E+01, 0.22571502E+01, 0.11304728E-01, -0.13671319E-04, 0.96819806E-08, -0.29307182E-11, 0.87417744E+04, 0.10757992E+02 in sequence;

[0111] The standard NASA coefficients of NH are 0.27836928E+01, 0.13298430E-02, -0.42478047E-06, 0.78348501E-10, -0.55044470E-14, 0.42120848E+05, 0.57407799E+01, 0.34929085E+01, 0.31179198E-03, -0.14890484E-05, 0.24816442E-08, -0.10356967E-11, 0.41880629E+05, 0.18483278E+01 in sequence;

[0112] The standard NASA coefficients of NH2 are 0.28347421E+01, 0.32073082E-02, -0.93390804E-06, 0.13702953E-09, -0.79206144E-14, 0.22171957E+05, 0.65204163E+01, 0.42040029E+01, -0.21061385E-02, 0.71068348E-05, -0.56115197E-08, 0.16440717E-11, 0.21885910E+05, -0.14184248E+00;

[0113] The standard NASA coefficients of NH3 are 0.26344521E+01, 0.56662560E-02, -0.17278676E-05, 0.23867161E-09, -0.12578786E-13, -0.65446958E+04, 0.65662928E+01, 0.42860274E+01, 0.46605230E-02, 0.21718513E-04, -0.22808887E-07, 0.82638046E-11, -0.67417285E+04, -0.62537277E+00;

[0114] The standard NASA coefficients of NO are 0.32606056E+01, 0.11911043E-02, -0.42917048E-06, 0.69457669E-10, -0.40336099E-14, 0.99209746E+04, 0.63693027E+01, 0.42184763E+01, -0.46389760E-02, 0.11041022E-04, -0.93361354E-08, 0.28035770E-11, 0.98446230E+04, 0.22808464E+01;

[0115] The standard NASA coefficients of NO2 are 0.48847542E+01, 0.21723956E-02, -0.82806906E-06, 0.15747510E-09, -0.10510895E-13, 0.23164983E+04, -0.11741695E+00, 0.39440312E+01, -0.15854290E-02, 0.16657812E-04, -0.20475426E-07, 0.78350564E-11, 0.28966179E+04, 0.63119917E+01;

[0116] The standard NASA coefficients of HCNO are 6.59860456E+00, 3.02778626E-03, -1.07704346E-06, 1.71666528E-10, -1.01439391E-14, 1.79661339E+04, -1.03306599E+01, 2.64727989E+00, 1.27505342E-02, -1.04794236E-05, 4.41432836E-09, -7.57521466E-13, 1.92990252E+04, 1.07332972E+01 in sequence;

[0117] The standard NASA coefficients of HOCN are 5.89784885E+00, 3.16789393E-03, -1.11801064E-06, 1.77243144E-10, -1.04339177E-14, -3.70653331E+03, -6.18167825E+00, 3.78604952E+00, 6.88667922E-03, -3.21487864E-06, 5.17195767E-10, 1.19360788E-14, -2.82698400E+03, 5.63292162E+00 in sequence;

[0118] The standard NASA coefficients of HNCO are 6.22395134E+00, 3.17864004E-03, -1.09378755E-06, 1.70735163E-10, -9.95021955E-15, -1.66599344E+04, -8.38224741E+00, 3.63096317E+00, 7.30282357E-03, -2.28050003E-06, -6.61271298E-10, 3.62235752E-13, -1.55873636E+04, 6.19457727E+00 in sequence;

[0119] The standard NASA coefficients of NCO are 0.51521845E+01, 0.23051761E-02, -0.88033153E-06, 0.14789098E-09, -0.90977996E-14, 0.14004123E+05, -0.25442660E+01, 0.28269308E+01, 0.88051688E-02, -0.83866134E-05, 0.48016964E-08, -0.13313595E-11, 0.14682477E+05, 0.95504646E+01 in sequence;

[0120] The standard NASA coefficients of CN are 0.37459805E+01, 0.43450775E-04, 0.29705984E-06, -0.68651806E-10, 0.44134173E-14, 0.51536188E+05, 0.27867601E+01, 0.36129351E+01, -0.95551327E-03, 0.21442977E-05, -0.31516323E-09, -0.46430356E-12, 0.51708340E+05, 0.39804995E+01 in sequence;

[0121] The standard NASA coefficients of HCNN are 0.58946362E+01, 0.39895959E-02, -0.15982380E-05, 0.29249395E-09, -0.20094686E-13, 0.53452941E+05, -0.51030502E+01, 0.25243194E+01, 0.15960619E-01, -0.18816354E-04, 0.12125540E-07, -0.32357378E-11, 0.54261984E+05, 0.11675870E+02 in sequence;

[0122] The standard NASA coefficients of N2 are 0.02926640E+02, 0.14879768E-02, 0.05684760E-05, 0.10097038E-09, -0.06753351E-13, -0.09227977E+04, 0.05980528E+02, 0.03298677E+02, 0.14082404E-02, -0.03963222E-04, 0.05641515E-07, -0.02444854E-10, -0.10208999E+04, 0.03950372E+02 in sequence;

[0123] The standard NASA coefficients of AR are 0.02500000E+02, 0.00000000E+00, 0.00000000E+00, 0.00000000E+00, 0.00000000E+00, -0.07453750E+04, 0.04366000E+02, 0.02500000E+02, 0.00000000E+00, 0.00000000E+00, 0.00000000E+00, 0.00000000E+00, -0.07453750E+04, 0.04366000E+02;

[0124] The standard NASA coefficients of C3H8 are 0.75341368E+01, 0.18872239E-01, -0.62718491E-05, 0.91475649E-09, -0.47838069E-13, -0.16467516E+05, -0.17892349E+02, 0.93355381E+00, 0.26424579E-01, 0.61059727E-05, -0.21977499E-07, 0.95149253E-11, -0.13958520E+05, 0.19201691E+02;

[0125] The standard NASA coefficients of C3H7 are 0.77026987E+01, 0.16044203E-01, -0.52833220E-05, 0.76298590E-09, -0.39392284E-13, 0.82984336E+04, -0.15480180E+02, 0.10515518E+01, 0.25991980E-01, 0.23800540E-05, -0.19609569E-07, 0.93732470E-11, 0.10631863E+05, 0.21122559E+02;

[0126] The standard NASA coefficients of CH3CHO are 0.54041108E+01, 0.11723059E-01, -0.42263137E-05, 0.68372451E-09, -0.40984863E-13, -0.22593122E+05, -0.34807917E+01, 0.47294595E+01, -0.31932858E-02, 0.47534921E-04, -0.57458611E-07, 0.21931112E-10, -0.21572878E+05, 0.41030159E+01 in sequence;

[0127] The standard NASA coefficients of CH2CHO are 0.05975670E+02, 0.08130591E-01, -0.02743624E-04, 0.04070304E-08, -0.02176017E-12, 0.04903218E+04, -0.05045251E+02, 0.03409062E+02, 0.10738574E-01, 0.01891492E-04, 0.07158583E-07, 0.02867385E-10, 0.15214766E+04, 0.09558290E+02 in sequence.

[0128] For different species, in the above NASA coefficient data, their corresponding high and low temperature ranges are marked. For example, for CH3CHO, its corresponding low temperature range is (200 - 1000K) and high temperature range is (1000 - 6000K). For CH2CHO, its corresponding low temperature range is (300 - 1000) and high temperature range is (1000 - 5000K); for H2, the first 7 are for the low temperature range (200 - 1000K) and the last 7 are for the high temperature range (1000 - 3500K). This segmented processing can more accurately fit the thermodynamic properties of substances in different temperature intervals.

[0129] In this embodiment, in the above NASA coefficient data, for each species, the 7th and 14th parameters are the entropy constants to be optimized and .

[0130] In step S3 of the embodiment of the present invention, the entropy constants of all species in the overall reaction (total number of species * 2 parameters) are optimized. Specifically, step S3 includes the following sub-steps:

[0131] S31. Form the corresponding minimalist mechanism according to the entropy constants of each reaction species;

[0132] S32. Calculate the combustion equilibrium temperatures corresponding to the minimalist mechanism and the detailed mechanism under different states within the set state range;

[0133] S33. Compare the combustion equilibrium temperatures corresponding to the minimalist mechanism and the detailed mechanism to obtain the relative error of the combustion equilibrium temperature under different states, and take the maximum value among them as the relative error of the combustion equilibrium temperature between the minimalist mechanism and the detailed mechanism within the set state range;

[0134] S34. Adjust the entropy constant values of the participating reaction species, and use the optimization algorithm to optimize the relative error of the combustion equilibrium temperature with different combinations of entropy constant values as inputs, and determine the combination of entropy constants corresponding to the minimum relative error of the combustion equilibrium temperature within the set state range as the entropy constant optimization result.

[0135] In this embodiment, the set state range includes a pressure range of 0.5 - 10 atm, a temperature range of 1000 - 2000 K, and an equivalence ratio range of 0.5 - 2.0.

[0136] In step S34 of this embodiment, when adjusting the entropy constant values of the participating reaction species, at the same state, for the same species, the change amount of its corresponding two entropy constant values is the same to ensure accurate calculation of the entropy value at the intermediate temperature (1000 K); for example, if the entropy constant is executed +1, then it is necessary to correspondingly execute +1 for

[0137] Step S34 of this embodiment includes the following sub-steps:

[0138] S34-1. Initialize and generate different combinations of entropy constant values as several points for the optimization algorithm;

[0139] S34-2. Sort the current several points according to the values of the objective function, and determine the worst point, the second-worst point, and the best point among them; where the objective function is the relative error of the combustion equilibrium temperature corresponding to different points;

[0140] S34-3. Calculate the center point of other points except the worst point;

[0141] S34-4. Calculate the reflection point according to the calculated center point;

[0142] When the relative error of the combustion equilibrium temperature corresponding to the reflection point is less than the relative error of the combustion equilibrium temperature corresponding to the best point, calculate the expansion point and determine whether the relative error of the combustion equilibrium temperature corresponding to the expansion point is less than the relative error of the combustion equilibrium temperature corresponding to the reflection point; if so, replace the current worst point with the expansion point and return to step S34-2; if not, replace the current worst point with the reflection point and return to step S34-2;

[0143] ​When the relative error of the combustion equilibrium temperature corresponding to the reflection point is less than the relative error of the combustion equilibrium temperature corresponding to the second worst point and greater than or equal to the relative error of the combustion equilibrium temperature corresponding to the optimal point, replace the current worst point with the reflection point and return to step S34-2;

[0144] When the relative error of the combustion equilibrium temperature corresponding to the reflection point is greater than or equal to the relative error of the combustion equilibrium temperature corresponding to the second worst point and less than the relative error of the combustion equilibrium temperature corresponding to the worst point, calculate the outer contraction point and determine whether the relative error of the combustion equilibrium temperature corresponding to the outer contraction point is less than the relative error of the combustion equilibrium temperature corresponding to the reflection point. If so, replace the current worst point with the outer contraction point and return to step S34-2; if not, replace all points except the optimal point and return to step S34-2;

[0145] When the relative error of the combustion equilibrium temperature corresponding to the reflection point is greater than or equal to the relative error of the combustion equilibrium temperature corresponding to the worst point, calculate the inner contraction point and determine whether the relative error of the combustion equilibrium temperature corresponding to the inner contraction point is less than the relative error of the combustion equilibrium temperature corresponding to the worst point. If so, replace the current worst point with the inner contraction point and return to step S34-2; if not, replace all points except the optimal point and return to step S34-2;

[0146] S34-5. Repeat steps S34-2 to S34-4 until the termination condition is met. Take the entropy constant combination corresponding to the optimal point with the minimum relative error of the combustion equilibrium temperature as the entropy constant optimization result; wherein, the termination condition is reaching the set number of iterations or the minimum relative error of the combustion equilibrium temperature being less than or equal to the set error threshold.

[0147] In this embodiment, the reflection point is , the expansion point is , the outer contraction point is , the inner contraction point is , and the replaced point is ;

[0148] In the formula, represents the calculated center point, represents the current worst point, represents the current optimal point, represents the point before replacement, represents the reflection coefficient, represents the expansion coefficient, represents the contraction coefficient, represents the fallback coefficient.

[0149] In this embodiment, a fast implementation method of the above optimization process is provided. The Nelder-Mead optimization function provided by the scipy library is used. This function only needs to input the function fun to be minimized and the initial value x0, without setting other optional parameters. Here, the function fun is the operation process for determining the relative error of the combustion equilibrium temperature, and the initial value x0 is the initial value of the entropy constant of each species mentioned above.

[0150] In an embodiment of the present invention, a specific experimental example of the above solution is provided.

[0151] In this embodiment, taking the hydrogen mechanism as an example, the relatively reliable KS mechanism is selected as the reference mechanism, and the hydrogen single-step mechanism reaction formula H2 + 0.5O2 <=> H2O is constructed. The initial entropy constants of each species are as follows in the table:

[0152] Table 2: Initial Entropy Constants of Each Species in the Hydrogen Single-Step Mechanism Reaction

[0153]

[0154] For the single-step mechanism, the relative error of the equilibrium temperature with the KS mechanism is evaluated within a wide range. Finally, the average relative error of the equilibrium temperature between the single-step mechanism and the KS mechanism is 8.91%, and the maximum relative error of the equilibrium temperature is 18.70%. When the equivalence ratio is 1, the distribution result of the relative error of the equilibrium temperature is as Figure 2 shown.

[0155] By using the method of the present invention, the entropy constants of each species in the single-step reaction are optimized, and the final results of the entropy constants of each species are shown in Table 3;

[0156] Table 3: Entropy Constants of Each Species in the Optimized Hydrogen Single-Step Mechanism Reaction

[0157]

[0158] Similarly, the equilibrium temperature error within a wide range is evaluated for the single-step mechanism after the entropy constant optimization. The results show that the average relative error of the equilibrium temperature is 1.53%, which is a decrease of 7.38% compared with the original single-step mechanism; the maximum relative error of the equilibrium temperature is 4.13%, which is a decrease of 14.57% compared with the original single-step mechanism. This proves the superiority of the method. Figure 3 Shows the distribution diagram of the relative error of the equilibrium temperature after the entropy constant optimization when the equivalence ratio is 1.

[0159] From Figure 2As can be seen, when the equivalence ratio is 1, the errors of the original single-step mechanism are generally large, especially in the high-temperature and low-pressure region. The maximum relative error reaches about 0.145 (14.5%) (red area). Even in the medium-pressure and temperature regions, there are obvious error gradients, indicating that the original mechanism has systematic deviations in predicting the thermodynamic equilibrium state. The overall average relative error is 8.96%, and the maximum error reaches 14.70%, and the accuracy does not meet the strict requirements; From Figure 3 As can be seen, the overall color of the error map tends to be cold, indicating that the errors are significantly reduced. Especially in the medium-high temperature and high-pressure regions, the errors are better controlled. The average error is reduced to 2.87%, compared with Figure 2 a decrease of 5.99%, and the maximum error is reduced to 4.13%, which is Figure 2 a reduction of 10.57% compared with Figure 2 and Figure 3 From the comparison results, after the entropy constant optimization, both the average and maximum relative errors have decreased significantly, intuitively proving that the entropy constant optimization method can effectively improve the description ability of the single-step mechanism for the thermodynamic equilibrium state.

[0160] In the present invention, specific embodiments are used to elaborate the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

[0161] Those of ordinary skill in the art will realize that the embodiments described herein are for helping readers understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations that do not depart from the essence of the present invention according to the technical revelations disclosed in the present invention, and these deformations and combinations are still within the protection scope of the present invention.

Claims

1. A minimalist mechanism generation method based on entropy constant correction, characterized in that, It includes the following steps: S1. Construct a single-step reaction equation when the fuel is fully burned, and then determine the species participating in the reaction; S2. Determine the standard NASA7 coefficients of the species participating in the reaction, and find the entropy constant to be optimized; S3. For all species participating in the reaction, using their current entropy constant as the initial value, with the goal of minimizing the relative error of the combustion equilibrium temperature between the reduced mechanism and the detailed mechanism within the set state range, optimize the entropy constant; During the optimization process, adjust the entropy constant values of the species participating in the reaction, and use different combinations of entropy constant values as inputs to optimize the relative error of the combustion equilibrium temperature using an optimization algorithm; S4. Generate a reduced mechanism based on the optimized entropy constant.

2. The minimalist mechanism generation method based on entropy constant correction according to claim 1, wherein, The specific content of step S1 is as follows: According to the numbers of carbon atoms, hydrogen atoms and oxygen atoms in the fuel used, calculate the stoichiometric coefficient of oxygen required for complete combustion; According to the stoichiometric coefficient of oxygen, construct a single-step reaction equation for the fuel used, and determine the species participating in the reaction.

3. The minimalist mechanism generation method based on entropy constant correction according to claim 1, wherein In step S2, among the standard NASA7 coefficients of the species participating in the reaction, the 7th and 14th parameters are used as the entropy constants to be optimized.

4. The minimalist mechanism generation method based on entropy constant correction according to claim 1, characterized in that Step S3 includes the following sub-steps: S31. Form the corresponding reduced mechanism according to the entropy constant of each species participating in the reaction; S32. Calculate the combustion equilibrium temperatures corresponding to the reduced mechanism and the detailed mechanism under different states within the set state range; S33. Compare the combustion equilibrium temperatures corresponding to the reduced mechanism and the detailed mechanism, obtain the relative error of the combustion equilibrium temperature under different states, and take the maximum value as the relative error of the combustion equilibrium temperature between the reduced mechanism and the detailed mechanism within the set state range; S34. Adjust the entropy constant values of the species participating in the reaction, and use different combinations of entropy constant values as inputs to optimize the relative error of the combustion equilibrium temperature using an optimization algorithm, and determine the combination of entropy constants corresponding to the minimum relative error of the combustion equilibrium temperature within the set state range as the optimization result of the entropy constant.

5. The minimalist mechanism generation method based on entropy constant correction according to claim 1, characterized in that, The set state range includes a pressure range of 0.5 - 10 atm, a temperature range of 1000 - 2000 K, and an equivalence ratio range of 0.5 - 2.

0.

6. The minimalist mechanism generation method based on entropy constant correction according to claim 4, characterized in that In step S33, when adjusting the entropy constant values of the species participating in the reaction, under the same state, for the same species, the change amounts of its corresponding two entropy constant values are the same.

7. The minimalist mechanism generation method based on entropy constant correction according to claim 4, characterized in that Step S34 includes the following sub-steps: S34-1. Initialize and generate different combinations of entropy constant values as several points of the optimization algorithm; S34-2. Sort the current several points according to the values of the objective function, and determine the worst point, the second-worst point and the best point among them; where the objective function is the relative error of the combustion equilibrium temperature corresponding to different points; S34-3. Calculate the center point of other points except the worst point; S34-4. Calculate the reflection point according to the calculated center point; When the relative error of the combustion equilibrium temperature corresponding to the reflection point is less than the relative error of the combustion equilibrium temperature corresponding to the optimal point, calculate the expansion point, and determine whether the relative error of the combustion equilibrium temperature corresponding to the expansion point is less than the relative error of the combustion equilibrium temperature corresponding to the reflection point; if so, replace the current worst point with the expansion point, and return to step S34-2; if not, replace the current worst point with the reflection point, and return to step S34-2; When the relative error of the combustion equilibrium temperature corresponding to the reflection point is less than the relative error of the combustion equilibrium temperature corresponding to the second worst point and greater than or equal to the relative error of the combustion equilibrium temperature corresponding to the optimal point, replace the current worst point with the reflection point, and return to step S34-2; When the relative error of the combustion equilibrium temperature corresponding to the reflection point is greater than or equal to the relative error of the combustion equilibrium temperature corresponding to the second worst point and less than the relative error of the combustion equilibrium temperature corresponding to the worst point, calculate the outer contraction point, and determine whether the relative error of the combustion equilibrium temperature corresponding to the outer contraction point is less than the relative error of the combustion equilibrium temperature corresponding to the reflection point; if so, replace the current worst point with the outer contraction point, and return to step S34-2; if not, replace all points except the optimal point, and return to step S34-2; When the relative error of the combustion equilibrium temperature corresponding to the reflection point is greater than or equal to the relative error of the combustion equilibrium temperature corresponding to the worst point, calculate the inner contraction point, and determine whether the relative error of the combustion equilibrium temperature corresponding to the inner contraction point is less than the relative error of the combustion equilibrium temperature corresponding to the worst point; if so, replace the current worst point with the inner contraction point, and return to step S34-2; if not, replace all points except the optimal point, and return to step S34-2; S34-5. Repeat steps S34-2 to S34-4 until the termination condition is met, and use the entropy constant combination corresponding to the optimal point with the minimum relative error of the combustion equilibrium temperature as the entropy constant optimization result; where the termination condition is reaching the set number of iterations or the minimum relative error of the combustion equilibrium temperature being less than or equal to the set error threshold.

8. The minimalist mechanism generation method based on entropy constant correction according to claim 7, characterized in that, The reflection point is , the expansion point is , the outward contraction point is , the inward contraction point is , the replaced point is ; In the formula, represents the calculated center point, represents the current worst point, represents the current best point, represents the point before replacement, represents the reflection coefficient, represents the expansion coefficient, represents the contraction coefficient, represents the back-off coefficient.

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