Combustion chamber nitrogen oxide emission prediction method and device, equipment and medium

Abstract

The invention discloses a prediction method, device and equipment for combustion chamber nitrogen oxide emission and a medium, the prediction method comprises the steps that calculation is conducted on multiple encrypted target grids through a fluid dynamic model, a parameter field of a simulation combustion chamber is obtained, and the parameter field comprises one or more of a velocity field, a component field and a temperature field; dividing the simulated combustion chamber into a pure flow area, a combustion reaction area and a post-combustion area according to the airflow flowing direction and the combustion reaction progress of the simulated combustion chamber; according to the parameter field and a corresponding first preset condition, the pure flow zone and the combustion reaction zone are partitioned, a plurality of zones are obtained, and the zones serve as a plurality of grid chemical reactors; and calculating the plurality of chemical reactors by utilizing a fluid dynamic model according to a chemical reaction mechanism to obtain the concentration of the nitric oxide at the outlet of the simulated combustion chamber. According to the embodiment of the invention, the emission amount of the nitric oxide in the combustion chamber can be accurately predicted, and the error is small.

Description

Technical Field

[0001] This application belongs to the field of predicting nitrogen oxide emissions in combustion chambers, and particularly relates to a method, device, equipment, and medium for predicting nitrogen oxide emissions in combustion chambers. Background Technique

[0002] Combustion chamber NOx emissions are one of the important conditions for market access of heavy-duty gas turbines (hereinafter referred to as "gas turbines"), and are also evaluation indicators for measuring the advantages and disadvantages of combustion chamber design methods. Achieving rapid prediction and analysis of NOx emissions under wide operating conditions of the combustion chamber is an important way to shorten the iterative optimization design cycle of the combustion chamber.

[0003] The Computational Fluid Dynamics-Chemical Reactor Network (CFD-CRN) method is one of the main methods for predicting nitrogen oxides (NOx) at present. In the CFD-CRN method in related technologies, first, computational fluid dynamics (CFD) simulation is used to obtain the flow field, temperature field, etc., and then the simulation results of the chemical reactor network (CRN) are used. According to a certain zoning criterion, the combustion chamber calculation domain is divided into interconnected ideal chemical reactors, and then a detailed chemical reaction mechanism is used to solve the CRN to predict NOx emissions. Among them, the zoning criterion used by CRN is the key factor affecting the calculation accuracy, and the realization of grid independence in CFD calculation is the main link affecting the calculation efficiency. The usual method is to encrypt the existing initial grid multiple times, so the encryption criterion is also an important factor affecting the calculation accuracy.

[0004] However, the CFD-CRN method in related technologies is currently applicable to a single operating condition, and large errors will occur when applied to other operating conditions. Therefore, there is a large error between the amount of nitrogen oxide generated and the predicted amount in the prediction method in related technologies, and it is urgently needed to be modified. Summary of the Invention

[0005] The embodiments of this application provide a method, device, equipment, and medium for predicting nitrogen oxide emissions in a combustion chamber, which can quickly and accurately predict nitrogen oxide emissions in the combustion chamber on the basis of reducing the calculation amount.

[0006] In a first aspect, the embodiments of this application provide a method for predicting nitrogen oxide emissions in a combustion chamber. The prediction method includes:

[0007] Calculating on multiple encrypted target grids using a fluid dynamics model to obtain a parameter field of the simulated combustion chamber, where the parameter field includes one or more of a velocity field, a component field, and a temperature field;

[0008] The simulated combustion chamber is divided into a pure flow region, a combustion reaction region, and a post-combustion region according to the air flow direction and the progress of the combustion reaction in the simulated combustion chamber;

[0009] The pure flow region and the combustion reaction region are respectively partitioned according to the parameter field and the corresponding first preset conditions to obtain a plurality of regions, and the plurality of regions are used as a plurality of grid chemical reactors;

[0010] The concentrations of nitrogen oxides at the outlet of the simulated combustion chamber are obtained by calculating the plurality of chemical reactors using a fluid dynamics model according to the chemical reaction mechanism.

[0011] In some alternative embodiments, the parameter field includes: oxygen mass fraction, fuel gas mass fraction, axial air flow velocity, and fuel consumption rate; the first preset conditions include a first preset threshold group and a second preset threshold group;

[0012] The pure flow region and the combustion reaction region are respectively partitioned according to the parameter field and the first preset conditions of the simulated combustion chamber to obtain a plurality of regions, including:

[0013] The pure flow region is divided into an air inlet region, a fuel inlet region, and a premixed region according to the oxygen mass fraction, the fuel gas mass fraction, and the corresponding first preset threshold group;

[0014] The combustion reaction region is divided into a recirculation region, a flame front region, and a main flame region according to the axial air flow velocity, the fuel consumption rate, and the corresponding second preset threshold group.

[0015] In some alternative embodiments, the pure flow region is divided into an air inlet region, a fuel inlet region, and a premixed region according to the oxygen mass fraction, the fuel gas mass fraction, and the corresponding first preset threshold group, including:

[0016] The region in the pure flow region where the oxygen mass fraction Y O2 ≥ 0.229 is divided into the air inlet region;

[0017] The region in the pure flow region where the fuel mass fraction Y f ≥ 0.999 is divided into the fuel inlet region;

[0018] The remaining region in the pure flow region is divided into the premixed region.

[0019] In some alternative embodiments, the parameter field includes: local equivalence ratio and average equivalence ratio in the premixed region;

[0020] After the remaining region in the pure flow region is divided into the premixed region, the prediction method further includes:

[0021] The premixed region is divided into a first fuel-rich region and a first fuel-lean region according to the local equivalence ratio and the average equivalence ratio in the premixed region, wherein the local equivalence ratio of the first fuel-rich region ≥Average equivalence ratio of the premixed zone Local equivalence ratio of the first fuel lean zone <Average equivalence ratio of the premixed zone

[0022] In some alternative embodiments, according to the axial gas flow velocity, the fuel consumption rate, and the corresponding second preset threshold group, the combustion reaction zone is divided into a recirculation zone, a flame front zone, and a main flame zone, including:

[0023] Dividing the region where the axial gas flow velocity v a ≤0 into the recirculation zone;

[0024] Dividing the region where the fuel consumption rate η < 99% into the flame front zone;

[0025] Dividing the remaining region in the combustion reaction zone into the main flame zone.

[0026] In some alternative embodiments, after dividing the region where the fuel consumption rate η < 99% into the flame front zone, the prediction method further includes:

[0027] According to the fuel consumption rate, the local equivalence ratio before combustion, and the corresponding third preset threshold group, dividing the flame front zone into a second fuel rich zone and a second fuel lean zone.

[0028] In some alternative embodiments, according to the fuel consumption rate, the local equivalence ratio before combustion, and the corresponding third preset threshold group, dividing the flame front zone into a second fuel rich zone and a second fuel lean zone, including:

[0029] According to the fuel consumption rate η ≤ 90% and the fuel consumption rate satisfying 90% < η ≤ 99%, dividing the flame front zone into a first region and a second region along the axis of the simulated combustion chamber;

[0030] According to the average equivalence ratio φ f of the flame front zone and the local equivalence ratio φ 0 before combustion, dividing the first region into a second fuel rich zone and a second fuel lean zone along the axis of the simulated combustion chamber; dividing the second region into a third fuel rich zone and a third fuel lean zone, where the φ 0 of the second fuel rich zone ≥ φ f , the φ 0 of the second fuel lean zone < φ f , the φ 0 of the third fuel rich zone ≥ φ f , and the φ 0 of the third fuel lean zone < φ f .

[0031] In some alternative embodiments, after dividing the remaining region in the combustion reaction zone into the main flame zone, the prediction method further includes:

[0032] According to the local equivalence ratio φ before combustion 0 , the main flame is divided into a fourth fuel-rich zone and a fourth fuel-lean zone, where the φ of the fourth fuel-rich zone 0 ≥φ m , and the φ of the fourth fuel-lean zone 0 <φ m .

[0033] In some alternative embodiments, before calculating using a hydrodynamic model on multiple encrypted target grids to obtain the parameter field of the simulated combustion chamber, the prediction method further includes:

[0034] Performing multiple encryption processes on the encrypted region using an encryption criterion until the concentration of nitrogen oxides does not change with the total number of target grids, to obtain multiple encrypted target grids.

[0035] In some alternative embodiments, before performing multiple encryption processes on the encrypted region using an encryption criterion until the concentration of nitrogen oxides does not change with the total number of target grids, to obtain multiple encrypted target grids, the prediction method further includes:

[0036] Performing a first division on the computational domain of the simulated combustion chamber to obtain initial grids;

[0037] Calculating using a hydrodynamic model based on the initial grids to obtain the maximum velocity gradient and the maximum turbulent kinetic energy gradient

[0038] According to the maximum velocity gradient and the maximum turbulent kinetic energy gradient Performing a second division on the initial grids to obtain a central zone, an annular zone, and a post-combustion zone;

[0039] Under a second preset condition, determining the encrypted regions in the central zone, the annular zone, and the post-combustion zone.

[0040] In some alternative embodiments, the second preset condition includes:

[0041] The central zone and the annular zone satisfy: the region;

[0042] The post-combustion zone satisfies: the region.

[0043] In some alternative embodiments, performing multiple encryption processes on the encrypted region using an encryption criterion until the concentration of nitrogen oxides does not change with the total number of target grids, to obtain multiple encrypted target grids, includes:

[0044] Using different velocity gradients for the encrypted region Perform encryption processing according to the encryption criterion. The encryption processing includes adding a new grid point at the midpoint of each grid line within the encrypted area, so that an initial three-dimensional grid becomes eight new grids.

[0045] In some alternative embodiments, calculate multiple chemical reactors according to the chemical reaction mechanism using a hydrodynamic model to obtain the concentration of nitrogen oxides at the outlet of the simulated combustion chamber, including:

[0046] Calculate multiple chemical reactors according to the chemical reaction mechanism using a hydrodynamic model to obtain the physical parameters in the grid. The physical parameters include volume, average pressure, temperature, and mass flow rate;

[0047] According to the physical parameters, use reaction kinetics software to calculate and solve multiple chemical reactors to obtain the components and temperature in each chemical reactor;

[0048] According to the components and temperature in the chemical reactor, obtain the concentration of nitrogen oxides at the outlet of the simulated combustion chamber.

[0049] In a second aspect, an embodiment of the present application provides a prediction device for nitrogen oxide emissions from a combustion chamber, including:

[0050] A data acquisition module, configured to calculate using a hydrodynamic model on multiple encrypted target grids to obtain a parameter field of the simulated combustion chamber. The parameter field includes one or more of a velocity field, a component field, and a temperature field;

[0051] A first partitioning module, configured to divide the simulated combustion chamber into a pure flow area, a combustion reaction area, and a post-combustion area according to the airflow direction of the simulated combustion chamber and the progress of the combustion reaction;

[0052] A second partitioning module, configured to partition the pure flow area and the combustion reaction area respectively according to the parameter field of the simulated combustion chamber and a first preset condition to obtain multiple areas, and use the multiple areas as multiple grid chemical reactors;

[0053] A calculation module, configured to calculate multiple chemical reactors according to the chemical reaction mechanism using a hydrodynamic model to obtain the concentration of nitrogen oxides at the outlet of the simulated combustion chamber.

[0054] In a third aspect, an embodiment of the present application provides a prediction electronic device for nitrogen oxide emissions from a combustion chamber, including: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, the prediction method for nitrogen oxide emissions from the combustion chamber in the first aspect is implemented.

[0055] Fourthly, an embodiment of the present application provides a computer-readable storage medium, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the prediction method for the nitrogen oxide emissions of the combustion chamber in the first aspect is implemented.

[0056] Fifthly, an embodiment of the present application provides a computer program product. When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device is enabled to implement the prediction method for the nitrogen oxide emissions of the combustion chamber in the first aspect.

[0057] The embodiments of the present application provide a prediction method, device, equipment and medium for the nitrogen oxide emissions of a combustion chamber. Under different working conditions, the combustion chamber airflow direction and the combustion reaction progress are used for zoning. According to the combustion reaction progress, the main generation areas of nitrogen oxides (NOx) with a relatively fast combustion reaction rate are divided, which can reduce the number of chemical reactors, reduce the calculation amount, and make the zoning criterion of the simulated combustion chamber universal under various working conditions, improving the prediction accuracy. The combustion chamber airflow direction can reflect the non-uniformity of fuel / air, and this non-uniformity is a key factor affecting the NOx concentration in the combustion chamber. Zoning according to the airflow direction can reduce the number of chemical reactors and the calculation amount. Combining the two can appropriately zone the simulated combustion chamber, so that the grid chemical reactors have an appropriate number, and on the basis of reducing the calculation amount, improve the accuracy of predicting the nitrogen oxide emissions of the combustion chamber. Description of the Drawings

[0058] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0059] Figure 1 Shows a schematic longitudinal section of a gas turbine combustion chamber.

[0060] Figure 2 Shows a schematic cross-section of the head of the gas turbine combustion chamber in Embodiment 1.

[0061] Figure 3 Shows a flowchart of the prediction method for the nitrogen oxide emissions of the combustion chamber provided by an embodiment of the present application.

[0062] Figure 4 Shows a schematic diagram of the initial grid of the simulated combustion chamber in an embodiment of the present application.

[0063] Figure 5 Shows a comparison diagram before and after the encryption of the annular area in an embodiment of the present application.

[0064] Figure 6Shows the schematic diagram of the target grid after encryption of the simulated combustion chamber in an embodiment of the present application.

[0065] Figure 7 Is the structural schematic diagram of the prediction device for the nitrogen oxide emission of the combustion chamber provided in an embodiment of the present application;

[0066] Figure 8 Shows the hardware structural schematic diagram of the prediction electronic device for the nitrogen oxide emission of the combustion chamber provided in an embodiment of the present application

[0067] Explanation of reference numerals:

[0068] 101, flow guiding bushing; 102, flame tube; 103, main combustion hole; 104, annular zone nozzle; 105, mixing hole; 106, transition section; 107, central nozzle; 200, prediction device; 201, data acquisition module; 202, first zoning module; 203, second zoning module; 204, calculation module; 300, prediction electronic device; 301, memory; 302, processor; 303, communication interface; 304, bus. Detailed implementation manners

[0069] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than limiting the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present application by showing examples of the present application.

[0070] Computational Fluid Dynamics-Chemical Reactor Network (CFD-CRN) is one of the main methods for predicting nitrogen oxides (NOx) at present. Among them, the zoning criterion used in the Chemical Reactor Network (CRN) is the key factor affecting the calculation accuracy. The zoning criterion includes two parts: one is the physical parameter for zoning; the other is to determine the zoning critical value or threshold of each physical parameter. Commonly used zoning criteria include arbitrary temperature criteria, substance component concentration criteria, etc.

[0071] In the related art, the zoning criterion in the prediction of nitrogen oxides (NOx) still needs to be determined by analyzing each working condition one by one. Even for the same combustion chamber, the applicable working condition range of these zoning criteria is small, only applicable to a single working condition, and large errors will occur when applied in other working conditions. This poses a challenge to predicting the NOx concentration in the combustion chamber and affects the accuracy of the prediction results.

[0072] To solve the above technical problems, the embodiments of the present application provide a method, device, equipment and medium for predicting the nitrogen oxide emissions of a combustion chamber. The following will introduce in detail a method, device, equipment and medium for predicting the nitrogen oxide emissions of a combustion chamber provided by the embodiments of the present application with reference to the accompanying drawings.

[0073] First, the combustion chamber provided by the embodiments of the application is introduced below, which can be the combustion chamber of a gas turbine.

[0074] Figure 1 Shows a schematic longitudinal section of a gas turbine combustion chamber. Figure 2 Shows a schematic cross-section of the head of the gas turbine combustion chamber in Embodiment 1.

[0075] See Figure 1 , the gas turbine combustion chamber includes a guide bushing 101, a flame tube 102, main combustion holes 103, an annular zone nozzle 104, mixing holes 105, a transition section 106, etc. The head of the combustion chamber adopts a radially graded structure, which is divided into a central nozzle and an annular zone. The inlet air flows along the guide bushing, and part of the air reaches the head of the combustion chamber.

[0076] Please refer to Figure 2 , through the annular zone nozzle 104 and the central nozzle 107 of the central swirler, fuel can be mixed and enter the interior of the flame tube 102, and another part of the air directly enters the flame tube 102 through the mixing holes 105 and the main combustion holes 103.

[0077] Figure 3 Shows a schematic flow chart of a method for predicting the nitrogen oxide emissions of a combustion chamber provided by the embodiments of the present application. As Figure 3 shown, the method for predicting the nitrogen oxide emissions of the combustion chamber may include steps S100 to S400.

[0078] Step 100, calculate using a hydrodynamic model on multiple encrypted target grids to obtain a parameter field of the simulated combustion chamber, where the parameter field includes one or more of a velocity field, a component field, and a temperature field.

[0079] In this step, the velocity field may include velocity vectors in three directions and a velocity gradient. The velocity vectors are usually in the x, y, and z directions in a Cartesian coordinate system, describing the movement speed and direction of the fluid at each point in space. The velocity gradient can represent the rate of change of the velocity in space. It can be an air flow velocity field, etc. The component field may include various chemical components in the combustion chamber and their mass fractions, generation rates, consumption rates, etc., such as CO 2 , N 2 , O 2 , CO, H 2Related components of components such as O and nitrogen oxides. Parameters in the temperature field include temperature, temperature gradient, heat flux density, etc. Heat flux density: The amount of heat passing through a unit area per unit time, which is a parameter closely related to the temperature field.

[0080] Step 200, divide the simulated combustion chamber into a pure flow zone, a combustion reaction zone, and a post-combustion zone according to the flow direction of the airflow in the simulated combustion chamber and the progress of the combustion reaction.

[0081] In this step, the pure flow zone refers to the area through which the airflow passes before combustion occurs, the combustion reaction zone is the area where the combustion reaction occurs, and the post-combustion zone refers to the area where the airflow flows after the combustion reaction ends. Among them, the content of nitrogen oxides in the post-combustion zone is relatively stable and can be less likely to be further subdivided into grids for calculation. In some alternative embodiments, in order to improve the prediction accuracy, the pure flow zone and the combustion reaction zone can be further subdivided.

[0082] Step 300, divide the pure flow zone and the combustion reaction zone respectively according to the parameter field and the corresponding first preset condition to obtain multiple regions, and use the multiple regions as multiple grid chemical reactors.

[0083] Step 400, calculate the concentration of nitrogen oxides at the outlet of the simulated combustion chamber by using the fluid dynamics model for multiple chemical reactors according to the chemical reaction mechanism.

[0084] According to the embodiments of the present application, the parameter field of the simulated combustion chamber is calculated by using the fluid dynamics model. Under different working conditions, the simulated combustion chamber is divided into a pure flow zone, a combustion reaction zone, and a post-combustion zone according to the flow direction of the airflow in the simulated combustion chamber and the progress of the combustion reaction. Among them, by dividing the main generation area of nitrogen oxides (NOx) with a relatively fast combustion reaction rate according to the progress of the combustion reaction, the number of chemical reactors can be reduced, the calculation amount can be reduced, and the zoning criterion of the simulated combustion chamber can be made universal under various working conditions, improving the prediction accuracy. The flow direction of the airflow in the combustion chamber can reflect the non-uniformity of fuel / air, and this non-uniformity is a key factor affecting the NOx concentration in the combustion chamber. By zoning according to the flow direction of the airflow, the number of chemical reactors can be reduced, and the calculation amount can be reduced. Then, secondary zoning is carried out, and the fluid dynamics model is used to calculate multiple chemical reactors to predict the concentration of nitrogen oxides at the outlet of the simulated combustion chamber. The simulated combustion chamber can be appropriately zoned to make the number of grid chemical reactors appropriate, and on the basis of reducing the calculation amount, the accuracy of predicting the nitrogen oxide emissions of the combustion chamber can be improved.

[0085] Since the present application divides the simulated combustion chamber into a pure flow zone, a combustion reaction zone, and a post-combustion zone according to the flow direction of the airflow in the simulated combustion chamber and the progress of the combustion reaction, it is applicable to multiple operating conditions of the same type of combustion chamber and has good prediction accuracy under multiple operating conditions.

[0086] As an example, the combustion chamber includes two operating modes, which are switched at a relative load Ne = 0.8: when Ne < 0.8, combustion occurs in the annular region; when Ne > 0.8, in order to reduce NOx emissions, the annular region serves as a premixed region and no combustion occurs. Thus, the combustion chamber can reduce NOx emissions by plugging the mixing holes or reducing the mixing hole diameter. The principle is that after the mixing hole diameter is reduced, the flow distribution changes, the air flow rate flowing to the head of the combustion chamber increases, the equivalence ratio of the combustion zone at the head of the combustion chamber decreases, and the flame temperature decreases, thereby reducing NOx emissions. Two operating conditions of the simulated combustion chamber corresponding to the combustion chamber are taken as examples.

[0087] In some alternative embodiments, before step 100 of calculating the parameter field of the simulated combustion chamber using the computational fluid dynamics model on multiple encrypted target grids, the prediction method further includes:

[0088] Step 050, performing multiple encryption processes on the encrypted region using an encryption criterion until the concentration of nitrogen oxides does not change with the total number of target grids, to obtain multiple encrypted target grids.

[0089] The encryption criterion of the embodiments of the present application is particularly applicable to dry low-NOx combustion chambers with a radial staging structure.

[0090] Performing multiple encryption processes on the encrypted region using an encryption criterion until the concentration of nitrogen oxides does not change with the total number of target grids can be understood as: the computational fluid dynamics model uses the NOx concentration as a criterion for judging grid independence during calculation.

[0091] In the calculation using the computational fluid dynamics model, the realization of grid independence is the main link affecting the calculation efficiency. The usual method is to perform multiple encryptions on the existing initial grid to form several sets of grids, and then use these grids for numerical calculation and observe the calculation results. When these results no longer change with the total number of grids, it is considered that grid independence has been achieved. In the related art, it is determined manually, but it is difficult for a single person to accurately judge the key regions that need to be encrypted, and often uniform encryption is carried out on the entire field. The conventional adaptive mesh refinement (AMR) technology can intelligently judge the grid encryption positions. Its basic principle is to set an encryption criterion and a given threshold, and the local grids in the computational domain that are greater than this encryption criterion threshold will be encrypted. The encryption criterion includes the physical parameters used and their thresholds, where the physical parameters include velocity gradient, temperature gradient, turbulent kinetic energy gradient, etc., which can be used alone or in combination; and the threshold determines the encryption range of the entire field.

[0092] This adaptive mesh refinement technology (AMR refinement technology) that utilizes physical parameters such as velocity gradient, temperature gradient, and turbulent kinetic energy gradient and their thresholds typically uses the same criterion throughout the entire field. However, due to the multi-scale characteristics of the combustion chamber mesh or the variation of multiple parameters, it is impossible to achieve refinement of all key regions during refinement. Moreover, in related technologies, the criterion for achieving grid independence is usually that the velocity field no longer changes, while ignoring that the NOx concentration is still changing with the number of grids, increasing the computational workload.

[0093] From this analysis, the hydrodynamic model of this application uses the NOx concentration as the criterion for judging grid independence during calculation. This method performs multiple refinement processes on the refinement region using the refinement criterion until the concentration of nitrogen oxides does not change with the total number of target grids, resulting in appropriately refined multiple target grids after refinement. On the basis of improving the accuracy of nitrogen oxides, the computational workload is reduced, and grid independence can be achieved with only one refinement during the calculation, improving the computational efficiency.

[0094] In addition, since the NOx concentration is the result of the combined action of the internal temperature field, component field, flow field, etc. of the combustion chamber, it is more reasonable for the present invention to use the NOx concentration as the criterion for grid independence.

[0095] In some optional embodiments, before step 050, that is, before performing multiple refinement processes using the refinement criterion until the concentration of nitrogen oxides does not change with the total number of target grids to obtain multiple refined target grids after refinement, the prediction method further includes:

[0096] Step 010, perform a first division on the computational domain of the simulated combustion chamber to obtain an initial grid;

[0097] In this step, any method can be used to divide the initial grid. For example, the partitioned structured grid generation method or the octree unstructured grid generation method can be used for division. As an example, a schematic diagram of the initial grid of the simulated combustion chamber is as Figure 4 shown. Calculations can be performed on this initial grid using the hydrodynamic model, or further partitioning can be carried out.

[0098] Step 020, perform calculations using the hydrodynamic model based on the initial grid to obtain the maximum velocity gradient and the maximum turbulent kinetic energy gradient

[0099] In this step, before step 020, the operating conditions can be obtained, and then calculations can be performed using the hydrodynamic model based on the initial grid.

[0100] Step 030, according to the maximum velocity gradient and the maximum turbulent kinetic energy gradient Perform a second division on the initial grid to obtain a central region, an annular region, and a post-combustion region;

[0101] Step 040, under a second preset condition, determine the encrypted regions in the central region, the annular region, and the post-combustion region.

[0102] In some alternative embodiments, in step 040, the second preset condition includes:

[0103] The central region and the annular region satisfy: the region;

[0104] The post-combustion region satisfies: the region.

[0105] In some alternative embodiments, step 050 performs multiple encryption processes on the encrypted regions using an encryption criterion until the concentration of nitrogen oxides does not change with the total number of target grids, obtaining multiple encrypted target grids, specifically including:

[0106] Use different velocity gradients in the encryption criterion to perform encryption processing on the encrypted regions. The encryption processing includes adding a new grid point at the midpoint of each grid line in the encrypted region, so that an initial three-dimensional grid becomes 8 new grids.

[0107] As an example, after performing encryption processing on the encrypted regions using different velocity gradients in the encryption criterion, multiple encrypted target grids of the simulated combustion chamber are obtained, as shown in Figure 5 . It can be seen from Figure 5 that the grids in Figure 5 are encrypted and refined in some regions compared to the grids in Figure 4 , and the grid density is higher in some regions.

[0108] As an example, step 040, under a second preset condition, determines the encrypted regions in the central region, the annular region, and the post-combustion region, specifically including one or more of the following:

[0109] Determine the region in the central region that satisfies the first velocity gradient threshold θ = 0.025 as the encrypted region of the central region;

[0110] Determine the region in the annular region that satisfies the second velocity gradient threshold θ = 0.05 as the encrypted region of the annular region; it can be understood in this step that: when the annular region satisfies the second velocity gradient threshold of 1, no encryption is required;

[0111] Determine the region in the combustion region that satisfies the third velocity gradient and turbulent kinetic energy gradient thresholds of 0.01 respectively as the encrypted region of the annular region.

[0112] As an example, the comparison diagrams of the annular region before and after encryption are as follows Figure 6 As shown, it can be seen from the figure that the grid density of some areas in the encrypted annular region is higher than that before encryption. This indicates that the encryption process has refined the grid, which is beneficial for taking into account the computational workload and more precisely subdividing the chemical reaction conditions in the grid, and can more accurately predict the emissions of nitrogen oxides.

[0113] In some embodiments, the method for determining the encrypted region in the encryption criterion includes: using the velocity gradient encryption criterion in the central region, setting the threshold θ = 0.025; using the velocity gradient encryption criterion in the annular region. Combustion occurs in the annular region, and the threshold θ = 0.05; no combustion occurs, and the threshold θ = 1; using the velocity gradient and the turbulent kinetic energy gradient joint encryption criterion in the post-combustion region, with the threshold θ = 0.01. Thus, on the basis of reducing the computational workload of calculations based on the hydrodynamic model, the prediction accuracy is improved.

[0114] In some alternative embodiments, in step 100, the parameter field includes: oxygen mass fraction, fuel gas mass fraction, axial gas flow velocity, and fuel consumption rate; the first preset condition includes a first preset threshold group and a second preset threshold group;

[0115] In order to further subdivide the grid of the simulated combustion chamber and improve the accuracy of nitrogen oxide emissions, in step 300, that is, partitioning the pure flow region and the combustion reaction region respectively according to the parameter field of the simulated combustion chamber and the first preset condition to obtain multiple regions, which specifically includes:

[0116] Step 310, dividing the pure flow region into an air inlet region, a fuel inlet region, and a premixed region according to the oxygen mass fraction, the fuel gas mass fraction, and the corresponding first preset threshold group;

[0117] Step 320, dividing the combustion reaction region into a recirculation region, a flame front region, and a main flame region according to the axial gas flow velocity, the fuel consumption rate, and the corresponding second preset threshold group.

[0118] According to the embodiments of the present application, the combustion reaction progress is reflected by the axial gas flow velocity and the fuel consumption rate η. η is a relative variable. Under different working conditions, the η criterion can be used to identify and divide the main NOx generation regions with a relatively fast combustion reaction rate, making the combustion chamber partitioning criterion universal under various working conditions and improving the accuracy of the prediction results.

[0119] In some alternative embodiments, according to the distribution position of the simulated combustion chamber, the recirculation region is divided into a central recirculation region and a corner recirculation region.

[0120] In some alternative embodiments, to further subdivide the grid of the simulated combustion chamber and improve the accuracy of nitrogen oxide emissions, in step 310, according to the oxygen mass fraction, the fuel mass fraction, and the corresponding first preset threshold group, the pure flow region is divided into an air inlet region, a fuel inlet region, and a premixed region, which specifically includes:

[0121] Step 311, divide the region in the pure flow region where the oxygen mass fraction Y O2 ≥ 0.229 into the air inlet region;

[0122] Step 312, divide the region in the pure flow region where the fuel mass fraction Y f ≥ 0.999 into the fuel inlet region;

[0123] Step 313, divide the remaining region in the pure flow region into the premixed region.

[0124] In some alternative embodiments, in step 100, the parameter field includes: the local equivalence ratio and the average equivalence ratio of the premixed region;

[0125] After step 313, which divides the remaining region in the pure flow region into the premixed region, the prediction method further includes:

[0126] Step 314, divide the premixed region into a first fuel-rich region and a first fuel-lean region according to the local equivalence ratio and the average equivalence ratio of the premixed region, where the local equivalence ratio of the first fuel-rich region ≥ the average equivalence ratio of the premixed region The local equivalence ratio of the first fuel-lean region < the average equivalence ratio of the premixed region

[0127] As an example, the calculation formula for the average equivalence ratio of the premixed region is:

[0128] where L 0 is the theoretical combustion air quantity of the fuel (kg air / kg fuel), G pf is the mass flow rate of the fuel entering the premixed region; G pa is the mass flow rate of the air entering the premixed region;

[0129] According to the embodiments of the present application, dividing by the average equivalence ratio accurately reflects the uneven premixing of fuel / air, and the uneven premixing is a key factor affecting the NOx concentration in the combustion chamber, thus ensuring the accuracy of the predicted nitrogen oxide results after zoning.

[0130] In some alternative embodiments, to further subdivide the grid of the simulated combustion chamber and improve the accuracy of nitrogen oxide emissions, in step 320, according to the axial gas flow velocity, the fuel consumption rate, and the corresponding second preset threshold group, the combustion reaction zone is divided into a recirculation zone, a flame front zone, and a main flame zone, which specifically includes:

[0131] Step 321, divide the region where the axial gas flow velocity v a ≤0 into the recirculation zone;

[0132] Step 322, divide the region where the fuel consumption rate η≤99% into the flame front zone;

[0133] Step 323, divide the remaining region in the combustion reaction zone into the main flame zone.

[0134] As an example, the definition of the fuel consumption rate η is:

[0135] where Y f is the local fuel mass fraction in the combustion reaction zone, and Y f，in is the fuel mass fraction at the inlet of the combustion reaction zone.

[0136] In some alternative embodiments, to further subdivide the grid of the simulated combustion chamber and improve the accuracy of nitrogen oxide emissions, after step 322 of dividing the region where the fuel consumption rate η<99% into the flame front zone, the prediction method further includes:

[0137] Step 324, according to the fuel consumption rate, the local equivalence ratio before combustion, and the corresponding third preset threshold group, divide the flame front zone into a second fuel-rich zone and a second fuel-lean zone.

[0138] In this step, the "two-dimensional" division method is used to subdivide the flame front zone, that is, the fuel consumption rate and the local equivalence ratio before combustion are subdivided, which is the grid subdivision of the simulated combustion chamber and improves the accuracy of the prediction result.

[0139] In some alternative embodiments, to further subdivide the grid of the simulated combustion chamber and improve the accuracy of nitrogen oxide emissions, step 324 of dividing the flame front zone into a second fuel-rich zone and a second fuel-lean zone according to the fuel consumption rate, the local equivalence ratio before combustion, and the corresponding third preset threshold group includes:

[0140] Step 3241, according to the fuel consumption rate η≤99% and the fuel consumption rate satisfying 90%<η≤99%, divide the flame front zone into a first region and a second region in the axial direction of the simulated combustion chamber;

[0141] Step 3242, according to the average equivalence ratio φ f of the flame front zone and the local equivalence ratio φ 0, in the axial direction of the simulated combustion chamber, the first region is divided into a second fuel-rich region and a second fuel-lean region; the second region is divided into a third fuel-rich region and a third fuel-lean region, where the φ of the second fuel-rich region 0 ≥φ f , the φ of the second fuel-lean region 0 <φ f , the φ of the third fuel-rich region 0 ≥φ f , the φ of the third fuel-lean region 0 <φ f .

[0142] As an example, the local equivalence ratio before combustion is calculated by the mass fractions of methane, oxygen, and combustion products containing carbon and hydrogen elements (including CO 2 , CO, H 2 O), and the calculation formula of is:

[0143]

[0144] In some alternative embodiments, after step 323 of dividing the remaining region in the combustion reaction zone into the main flame zone, the prediction method further includes:

[0145] Step 3231, according to the local equivalence ratio φ before combustion 0 , the main flame zone is divided into a fourth fuel-rich region and a fourth fuel-lean region, where the φ of the fourth fuel-rich region 0 ≥φ m , the φ of the fourth fuel-lean region 0 <φ m .

[0146] As an example, the average equivalence ratio of the pilot main flame zone, the calculation formula is:

[0147] where G mf is the mass flow rate of fuel entering the main flame zone; G ma is the mass flow rate of air entering the main flame zone;

[0148] In some alternative embodiments, in step 400, according to the chemical reaction mechanism, the fluid dynamics model is used to calculate multiple chemical reactors to obtain the concentration of nitrogen oxides at the outlet of the simulated combustion chamber, including:

[0149] Step 410, according to the chemical reaction mechanism, the fluid dynamics model is used to calculate multiple chemical reactors to obtain the physical parameters in the grid, and the physical parameters include volume, average pressure, temperature, and mass flow rate;

[0150] In this step, the volume can be the partition volume V, which is the sum of the volumes of the volume meshes within the partition; the average pressure P and temperature T of the reactor can be calculated using the volume-weighted average method:

[0151]

[0152] The mass flow rate between partitions can be calculated by performing an area integral on the product of the normal velocity v n at the contact surface between partitions and the density ρ;

[0153]

[0154] Step 420: According to the physical parameters, use reaction kinetics software to calculate and solve multiple chemical reactors to obtain the components and temperatures in each chemical reactor;

[0155] In this step, Cantera can be used to calculate and solve multiple chemical reactors. The reaction kinetics software can be software such as Gri-Mech 3.0.

[0156] Step 430: Obtain the concentration of nitrogen oxides at the outlet of the simulated combustion chamber based on the components and temperatures in the chemical reactor.

[0157] In this step, Cantera can be used to obtain the concentration of nitrogen oxides at the outlet of the simulated combustion chamber based on the components and temperatures in the chemical reactor. As an example, it can be converted to the NOx concentration under a 15% O 2 content, and the calculation formula can be:

[0158]

[0159] As an example 1, the operating conditions of the simulated combustion chamber can be: the mixing hole diameter D jet = 50.8 mm, the relative load Ne = 1.0 condition, and no combustion occurs in the annular region under this condition;

[0160] Step 1: Divide the initial calculation grid for the combustion chamber calculation domain;

[0161] Step 2: Use the initial grid to perform calculations using the hydrodynamic model to obtain the maximum velocity gradient and the maximum turbulent kinetic energy gradient

[0162] Among them, the detailed CFD calculations are as follows: The SIMPLE algorithm, Realizable k-ε turbulence model, and Eddy Dissipation combustion model are used. The reaction mechanism is the methane-air two-step reaction mechanism, and the DO (discrete ordinates) model is adopted for the radiation model; the operating pressure is set to 1486 kPa; the boundary conditions are set as follows: The "mass-flow-inlet" boundary condition is used for the air inlet: the flow rate is 15.4 kg / s and the temperature is 675 K; the "mass-flow-inlet" boundary condition is also used for the fuel inlet: the flow rate is 0.31 kg / s and the temperature is 288 K; the "outflow" boundary condition is used for the combustion chamber outlet; the combustion chamber wall is set as "wall", with a mixed heat boundary condition and an average heat transfer coefficient of 2868 W / (m 2 ·K);

[0163] Step 3: Divide the initial mesh of the combustion chamber into several regions: the central region, the annular region, and the post-combustion region; the following refinement criteria are set for each region: The velocity gradient refinement criterion is used for the central region, and the threshold θ = 0.025 is set; the velocity gradient refinement criterion is used for the annular region, and the threshold θ = 1; the velocity gradient and the turbulent kinetic energy gradient joint refinement criterion is used for the post-combustion region, and the threshold θ = 0.01;

[0164] Determine the refinement positions within each region. The positions in the central region are those that meet the following conditions:

[0165] The threshold for the annular region is 1, and no refinement is required;

[0166] The refinement positions in the post-combustion region are those that meet the following conditions:

[0167]

[0168] Add a new grid point at the midpoint of each grid line at the refinement positions to complete the refinement, resulting in multiple target grids after refinement.

[0169] Step 4: Perform calculations using the hydrodynamic model based on the multiple target grids after refinement to obtain parameter fields such as the velocity field, component field, and temperature field of the combustion chamber, and then construct a chemical reactor network, which specifically includes the following steps:

[0170] Step 5: Sequentially divide the internal region of the combustion chamber into three major regions: the pure flow region, the combustion reaction region, and the post-combustion region;

[0171] The pure flow region is subdivided into an air inlet region, a fuel inlet region, and a premixing region; among them, the fuel inlet region is further subdivided according to the nozzle type into: an annular region nozzle, a central nozzle, and a pilot fuel inlet region; the premixing region is also subdivided according to the nozzle type into: a central premixing region and an annular premixing region, and is divided into a fuel-rich region and a fuel-lean region according to the average equivalence ratio of the central premixing region and the average equivalence ratio of the annular premixing region The pure flow region contains a total of 8 regions. The names, numbers, partitioning criteria used, and regional locations of each region are shown in Table 1;

[0172] The combustion reaction region is subdivided into a recirculation region, a flame front region, and a main flame region; among them, the recirculation region is divided into a central recirculation region and a corner recirculation region according to the distribution location; the flame front region is divided into a pilot flame region, a central nozzle premixed flame, and an annular region outlet premixed flame according to the nozzle type. For the central nozzle flame and the annular region outlet flame adopting the premixed combustion mode, the two-dimensional partitioning method is used to further divide it into 8 regions; the main flame region is divided into a fuel-rich region and a fuel-lean region according to its average equivalence ratio The combustion reaction region contains a total of 13 regions. The names, numbers, partitioning criteria used, and regional locations of each region are shown in Table 1;

[0173] In the post-combustion region, the flow and mixing of the gas flow occur and are not further subdivided; the combustion chamber is divided into a total of 22 regions, as shown in Table 1.

[0174] Table 1 Partitioning criteria of the combustion chamber in Example 1

[0175]

[0176]

[0177] Step 6: Statistically calculate the volume V, average pressure P, temperature T of the 22 partitions, and the mass flow rate between the partitions; the partition volume V is the sum of the volumes of the body grids within the partition; the average pressure P and temperature T of the reactor are calculated using the volume-weighted average method: the mass flow rate between the partitions is calculated by performing an area integral on the product of the normal velocity v n of the contact surface between the partitions and the density ρ;

[0178] Step 7: Use the detailed chemical reaction mechanism of Gri-Mech 3.0 to solve the CRN, and calculate that the NOx concentration at the outlet of the combustion chamber is: 28.4 ppm (@15% O 2 ), while the experimental value, that is, the actual value is 29.1 ppm (@15% O 2 ), and the prediction error in this example is only 2.4%.

[0179] To illustrate the accuracy of the CRN zoning criterion proposed in Example 1, a comparative Example 1 using the temperature zoning criterion (Takahashi Dong et al., Automatic Generation Method of Chemical Reactor Network for Predicting NOx Emissions, Journal of Tsinghua University (Science and Technology), 2023, 63(04): 612-622) was compared. The calculation result of Comparative Example 1 was 6.67 ppm (@15% O 2 ), and the error reached 77.1%.

[0180] As another Example 2, the operating conditions of this combustion chamber include: the mixing hole diameter D jet = 69.85 mm, the relative load Ne = 0.5 condition, and there is combustion in the annular region under this condition. The initial grid design of this embodiment is the same as that of Example 1 above. In terms of adaptive grid encryption, the difference from Example 1 is only in the setting of the encryption criterion and threshold in the annular region: in this Example 2, the velocity gradient encryption criterion is used in the annular region and the threshold θ = 0.05. Then, the positions that need to be encrypted in the annular region are:

[0181]

[0182] In terms of zoning, the main difference between Example 2 and Example 1 is also in the annular region: since there is combustion in the annular region, it should be divided according to the criterion of the combustion reaction zone and is subdivided into the flame front zone and the main flame zone; among them, the flame front zone uses the two-dimensional division method and is subdivided into 4 zones; the main flame zone is divided into the fuel-rich zone and the lean zone according to the average equivalence ratio of the annular region . The annular region of Embodiment 2 contains a total of 6 zones. The names, numbers, zoning criteria used, and regional positions of each zone are shown in Table 2; the zoning criteria for the remaining zones are the same as those of Embodiment 1.

[0183] Table 2 Zoning criteria for the annular region of Example 2.

[0184]

[0185] The volume V, average pressure P, temperature T of all zones and the mass flow between zones were statistically calculated; the detailed chemical reaction mechanism of Gri-Mech 3.0 was used to solve the CRN, and the calculated NOx concentration at the combustion chamber outlet was: 92.6 ppm (@15% O2), while the experimental value, that is, the actual value, was 87 ppm (@15% O 2 ). The error of this Example 2 was only 6.4%, which also verified that the CRN zoning criterion proposed by the present invention is applicable to different load conditions under the same structure combustion chamber.

[0186] To illustrate the accuracy of Example 2, a comparison was made with Comparative Example 2 using the conventional CRN partitioning method (Takahashi Dong et al., Automatic Generation Method of Chemical Reactor Network for Predicting NOx Emissions, Journal of Tsinghua University (Science and Technology), 2023, 63(04): 612-622). The calculation result of Comparative Example 2 was 9.4 ppm (@15% O 2 ), and the error reached 89.1%.

[0187] Figure 7 The structural schematic diagram of the prediction device for nitrogen oxide emissions in a combustion chamber provided by an embodiment of the present application is shown. As Figure 7 shown, the prediction device 200 for nitrogen oxide emissions in the combustion chamber may include a data acquisition module 201, a first partitioning module 202, a second partitioning module 203, and a calculation module 204.

[0188] The data acquisition module 201 is configured to perform calculations using a hydrodynamic model on multiple encrypted target grids to obtain a parameter field of the simulated combustion chamber. The parameter field includes one or more of a velocity field, a component field, and a temperature field.

[0189] The first partitioning module 202 is configured to divide the simulated combustion chamber into a pure flow region, a combustion reaction region, and a post-combustion region according to the flow direction of the gas flow in the simulated combustion chamber and the progress of the combustion reaction.

[0190] The second partitioning module 203 is configured to partition the pure flow region and the combustion reaction region respectively according to the parameter field of the simulated combustion chamber and a first preset condition to obtain multiple regions, and use the multiple regions as multiple grid chemical reactors.

[0191] The calculation module 204 is configured to perform calculations on the multiple chemical reactors using a hydrodynamic model according to a chemical reaction mechanism to obtain the concentration of nitrogen oxides at the outlet of the simulated combustion chamber.

[0192] In some optional embodiments, the prediction device 200 for nitrogen oxide emissions in the combustion chamber further includes:

[0193] An encryption module, configured to perform multiple encryption processes on the encrypted region using an encryption criterion until the concentration of nitrogen oxides does not change with the total number of target grids, to obtain multiple encrypted target grids.

[0194] In some optional embodiments, the prediction device 200 for nitrogen oxide emissions in the combustion chamber further includes:

[0195] An initial partitioning module, configured to perform a first partitioning on the calculation domain of the simulated combustion chamber to obtain an initial grid.

[0196] A velocity calculation module, configured to perform calculations using a hydrodynamic model based on the initial grid to obtain the maximum velocity gradient and the maximum turbulent kinetic energy gradient

[0197] A speed initial encryption module, which is used to perform a second division on the initial grid according to the maximum speed gradient and the maximum turbulent kinetic energy gradient to obtain a central region, an annular region, and a post-combustion region;

[0198] A first encryption determination module, which is used to determine the encrypted regions in the central region, the annular region, and the post-combustion region under a second preset condition.

[0199] In some optional embodiments, in step 040, the second preset condition includes:

[0200] The central region and the annular region satisfy: regions;

[0201] The post-combustion region satisfies: regions.

[0202] In some optional embodiments, the encryption module includes:

[0203] An encryption execution module, which is used to perform encryption processing on the encrypted regions using different speed gradient encryption criteria. The encryption processing includes adding a new grid point at the midpoint of each grid line in the encrypted region, so that an initial three-dimensional grid becomes 8 new grids.

[0204] In some optional embodiments, the second partitioning module 203 specifically includes:

[0205] A pure flow region partitioning module, which is used to divide the pure flow region into an air inlet region, a fuel inlet region, and a premixed region according to the oxygen mass fraction, the fuel mass fraction, and the corresponding first preset threshold group;

[0206] A combustion reaction region partitioning module, which is used to divide the combustion reaction region into a recirculation region, a flame front region, and a main flame region according to the axial gas flow velocity and the fuel consumption rate and the corresponding second preset threshold group.

[0207] In some optional embodiments, the combustion reaction region partitioning module includes a recirculation region partitioning module, which is used to divide the recirculation region into a central recirculation region and a corner recirculation region according to the distribution position of the simulated combustion chamber.

[0208] In some optional embodiments, the pure flow region partitioning module specifically includes:

[0209] A first sub-module for partitioning the pure flow region, which is used to divide the region in the pure flow region where the oxygen mass fraction Y O2 ≥0.229 into an air inlet region;

[0210] The second partition submodule of the pure flow area is used to convert the fuel mass fraction Y in the pure flow area f The area ≥0.999 is divided into a fuel inlet area; the third partitioning submodule of the pure flow area is used to divide the remaining area in the pure flow area into a premixing area.

[0211] In some optional embodiments, the pure flow area partitioning module includes a premixing area partitioning module, which specifically includes: a premixing area partitioning submodule, which is used to divide the premixing area into a first fuel-rich area and a first fuel-lean area according to the local equivalence ratio and the average equivalence of the premixing area, wherein the local equivalence ratio of the first fuel-rich area is ≥ Average equivalent ratio of premixing zone Local equivalence ratio of the first fuel-lean region <Average equivalence ratio in premixing zone

[0212] In some optional embodiments, the combustion reaction zone partitioning module specifically includes: a reflow zone partitioning module, which is used to adjust the axial airflow velocity v a The area where the fuel consumption rate η is less than 99% is divided into the recirculation area; the flame front area zoning module is used to divide the area where the fuel consumption rate η is less than 99% into the flame front area; the main flame area zoning module is used to divide the remaining area in the combustion reaction area into the main flame area.

[0213] In some optional embodiments, the combustion reaction zone partitioning module specifically includes: a combustion reaction zone partitioning sub-module, which is used to divide the flame front zone into a second fuel-rich zone and a second fuel-lean zone according to the fuel consumption rate and the local equivalence ratio before combustion and the corresponding third preset threshold group.

[0214] In some optional embodiments, the combustion reaction zone partitioning submodule includes:

[0215] A one-dimensional partitioning module, used for dividing the flame front area in the axial direction of the simulated combustion chamber into a first area and a second area according to the fuel consumption rate η≤90% and the fuel consumption rate satisfying 90%<η≤90%;

[0216] Two-dimensional partitioning module for the flame front area according to the average equivalence ratio φ f and the local equivalence ratio before combustion φ o , the first region is divided into a second fuel-rich region and a second fuel-lean region in the axial direction of the simulated combustion chamber; the second region is divided into a third fuel-rich region and a third fuel-lean region, wherein the φ 0 ≥φ f , φ in the second fuel-lean region 0 <φ f , φ in the third fuel-rich region 0 ≥φ f , φ in the third fuel-lean region 0 <φ f .

[0217] In some alternative embodiments, the combustion reaction discrimination zone module specifically includes:

[0218] A fuel concentration zoning module, configured to divide the main flame zone into a fourth fuel-rich zone and a fourth fuel-lean zone according to the local equivalence ratio φ before combustion, where the φ of the fourth fuel-rich zone 0 , and the φ of the fourth fuel-lean zone 0 ≥φ m , and the φ of the fourth fuel-lean zone 0 <φ m .

[0219] In some alternative embodiments, the calculation module 204 includes:

[0220] A physical parameter calculation module, configured to calculate multiple chemical reactors according to a chemical reaction mechanism using a computational fluid dynamics model to obtain physical parameters in the grid, where the physical parameters include volume, average pressure, temperature, and mass flow rate;

[0221] A chemical reactor state calculation module, configured to calculate and solve multiple chemical reactors according to the physical parameters using reaction kinetics software to obtain the components and temperature in each chemical reactor;

[0222] A nitrogen oxide prediction sub-module, configured to obtain the concentration of nitrogen oxides at the outlet of the simulated combustion chamber according to the components and temperature in the chemical reactor.

[0223] Figure 8 FIG. shows a schematic hardware structure diagram of a prediction electronic device for nitrogen oxide emissions from a combustion chamber provided in an embodiment of the present application.

[0224] As Figure 8 shown, the prediction electronic device 300 for nitrogen oxide emissions from a combustion chamber includes a memory 301, a processor 302, and a computer program stored on the memory 301 and executable on the processor 302. When the processor 301 executes the program, the steps in any of the above method embodiments are implemented.

[0225] Exemplarily, the program may be divided into one or more modules / units, and one or more modules / units are stored in the memory 302 and executed by the processor 301 to complete the present application. One or more modules / units may be a series of program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the program in the device.

[0226] Specifically, the above-mentioned processor 301 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured as one or more integrated circuits for implementing the embodiments of the present application.

[0227] The memory 302 may include a mass memory for data or instructions. By way of example and not limitation, the memory 302 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. In a suitable case, the memory 302 may include a removable or non-removable (or fixed) medium. In a suitable case, the memory 302 may be internal or external to the integrated gateway disaster recovery device. In a specific embodiment, the memory 302 is a non-volatile solid-state memory.

[0228] The memory 301 may include a read-only memory (ROM), a random access memory (RAM), a magnetic disk storage medium device, an optical storage medium device, a flash memory device, an electrical, optical, or other physical / tangible memory storage device. Thus, generally, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method for predicting the nitrogen oxide emissions of the combustion chamber according to the embodiments of the present application.

[0229] The processor 302 runs a computer program corresponding to the executable program code by reading the executable program code stored in the memory 301, so as to implement the method for predicting the nitrogen oxide emissions of the combustion chamber in the above embodiments.

[0230] In some examples, the prediction electronic device 300 for the nitrogen oxide emissions of the combustion chamber may further include a communication interface 303 and a bus 304. Among them, as Figure 8 shown, the memory 301, the processor 302, and the communication interface 303 are connected through the bus 304 and complete communication with each other.

[0231] The communication interface 303 is mainly used to implement communication between the various modules, devices, units, and / or devices in the embodiments of the present application. The input device and / or output device may also be accessed through the communication interface 303.

[0232] The bus 304 includes hardware, software, or both, and couples the components of the prediction electronic device 300 for combustion chamber nitrogen oxide emissions to each other. By way of example and not limitation, the bus 304 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low pin count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-E) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses or a combination of two or more of these. Where appropriate, the bus 304 may include one or more buses. Although the embodiments of the present application describe and illustrate specific buses, the present application contemplates any suitable bus or interconnect.

[0233] The fourth aspect of the present application further provides a computer-readable storage medium, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the prediction method for combustion chamber nitrogen oxide emissions in the above embodiments can be implemented, and the same technical effects can be achieved. To avoid repetition, it will not be elaborated here. Among them, the above computer-readable storage medium may include a non-transitory computer-readable storage medium, such as a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disc, etc., which is not limited herein.

[0234] The embodiments of the present application provide a computer program product. When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device is caused to execute the prediction method for combustion chamber nitrogen oxide emissions in the above embodiments, and the same technical effects can be achieved. To avoid repetition, it will not be elaborated here.

[0235] It should be clear that the various embodiments in this specification are all described in a progressive manner. For the parts that are the same or similar among the various embodiments, reference can be made to each other. The key point of each embodiment is to illustrate the differences from other embodiments. For the apparatus embodiments, device embodiments, computer-readable storage medium embodiments, and computer program product embodiments, reference can be made to the description part of the method embodiments for the relevant parts. This application is not limited to the specific steps and structures described above and shown in the figures. Those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of this application. And, for the sake of simplicity, the detailed description of known method technologies is omitted here.

[0236] The above has described various aspects of this application with reference to the flowcharts and / or block diagrams of the methods, apparatuses (systems), and computer program products according to the embodiments of this application. It should be understood that each block in the flowchart and / or block diagram, and the combination of each block in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing devices to generate a machine, such that these instructions executed by the processor of the computer or other programmable data processing devices enable the implementation of the functions / actions specified in one or more blocks of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It should also be understood that each block in the block diagram and / or flowchart, and the combination of the blocks in the block diagram and / or flowchart, can also be implemented by dedicated hardware that performs the specified functions or actions, or can be implemented by the combination of dedicated hardware and computer instructions.

[0237] Those skilled in the art should be able to understand that the above embodiments are all exemplary rather than restrictive. Different technical features that appear in different embodiments can be combined to achieve beneficial effects. Those skilled in the art should be able to understand and implement other variant embodiments of the disclosed embodiments based on the study of the drawings, the specification, and the claims. In the claims, the term "comprising" does not exclude other devices or steps; the quantifier "one" does not exclude a plurality; the terms "first" and "second" are used to label names rather than to indicate any specific order. Any reference signs in the claims should not be construed as limiting the scope of protection. The functions of multiple parts in the claims can be implemented by a single hardware or software module. The fact that certain technical features appear in different dependent claims does not mean that these technical features cannot be combined to achieve beneficial effects.

Claims

1. A method for predicting combustion chamber nitrogen oxide emissions, characterized in that: The prediction method comprises: Calculating using a fluid dynamics model on the encrypted multiple target grids to obtain a parameter field of a simulated combustion chamber, wherein the parameter field includes one or more of a velocity field, a component field, and a temperature field; The simulated combustion chamber is divided into a pure flow zone, a combustion reaction zone and a post-combustion zone according to the airflow direction and the combustion reaction progress in the simulated combustion chamber; Partitioning the pure flow area and the combustion reaction area according to the parameter field and the corresponding first preset condition to obtain a plurality of areas, and using the plurality of areas as a plurality of grid chemical reactors; The concentration of nitrogen oxides at the outlet of the simulated combustion chamber is obtained by calculating the concentration of nitrogen oxides at the outlet of the simulated combustion chamber using a fluid dynamics model according to the chemical reaction mechanism.

2. The prediction method according to claim 1, characterized in that: The parameter field includes: oxygen mass fraction, fuel gas mass fraction, axial airflow velocity and fuel consumption rate; the first preset condition includes a first preset threshold group and a second preset threshold group; The pure flow area and the combustion reaction area are divided into zones according to the parameter field of the simulated combustion chamber and the first preset condition to obtain a plurality of zones, including: According to the oxygen mass fraction and the fuel gas mass fraction and the corresponding first preset threshold value group, the pure flow area is divided into an air inlet area, a fuel inlet area and a premixing area; According to the axial air flow velocity and the fuel consumption rate and the corresponding second preset threshold value group, the combustion reaction zone is divided into a recirculation zone, a flame front zone and a main flame zone.

3. The prediction method according to claim 2, characterized in that: The method of dividing the pure flow area into an air inlet area, a fuel inlet area and a premixing area according to the oxygen mass fraction and the fuel gas mass fraction and the corresponding first preset threshold value group includes: The oxygen mass fraction Y in the pure flow area O2 The area ≥0.229 is divided into the air inlet area; The fuel mass fraction Y in the pure flow region f The area ≥0.999 is divided into the fuel inlet area; The remaining area in the pure flow zone is divided into the premixing zone.

4. The prediction method according to claim 3, characterized in that: The parameter field includes: local equivalence ratio and average equivalence in the premixing zone; After dividing the remaining area in the pure flow area into the premixing area, the prediction method further includes: The premixing zone is divided into a first fuel-rich zone and a first fuel-lean zone according to the local equivalence ratio and the average equivalence of the premixing zone, wherein the local equivalence ratio of the first fuel-rich zone is ≥ Average equivalent ratio of premixing zone The local equivalence ratio of the first fuel lean region <Average equivalence ratio in premixing zone 5. The prediction method according to claim 2, characterized in that: The method of dividing the combustion reaction zone into a recirculation zone, a flame front zone and a main flame zone according to the axial airflow velocity and the fuel consumption rate and the corresponding second preset threshold value group includes: The axial air flow velocity v a The area ≤0 is divided into the reflow zone; The area with fuel consumption rate η<99% is divided into the flame front area; The remaining area in the combustion reaction zone is divided into the main flame zone.

6. The prediction method according to claim 5, characterized in that: After dividing the area with fuel consumption rate η<99% into flame front areas, the prediction method further comprises: The flame front area is divided into a second fuel-rich area and a second fuel-lean area according to the fuel consumption rate and the pre-combustion local equivalence ratio and the corresponding third preset threshold group.

7. The prediction method according to claim 6, characterized in that: The step of dividing the flame front area into a second fuel-rich area and a second fuel-lean area according to the fuel consumption rate and the local equivalence ratio before combustion and the corresponding third preset threshold group comprises: According to the fuel consumption rate η≤90% and the fuel consumption rate satisfies 90%<η≤99%, the flame front is divided into a first area and a second area in the axial direction of the simulated combustion chamber; According to the average equivalent ratio φ of the flame front area f and the local equivalence ratio φ0 before combustion, the first region is divided into a second fuel-rich region and a second fuel-lean region in the axial direction of the simulated combustion chamber; the second region is divided into a third fuel-rich region and a third fuel-lean region, wherein φ0 of the second fuel-rich region ≥ φ f , the second fuel lean region φ0<φ f , the third fuel-rich region φ0≥φ f , the third fuel lean region φ0<φ f .

8. The prediction method according to claim 5, characterized in that: After dividing the remaining area in the combustion reaction zone into the main flame zone, the prediction method further comprises: According to the local equivalence ratio φ0 before combustion, the main flame area is divided into a fourth fuel-rich area and a fourth fuel-lean area, wherein φ0 of the fourth fuel-rich area ≥ φ m , the fourth fuel lean region φ0<φ m .

9. The method according to claim 1, characterized in that: Before performing calculations using a fluid dynamics model on the encrypted multiple target grids to obtain a parameter field of a simulated combustion chamber, the prediction method further includes: The encrypted area is encrypted multiple times using an encryption criterion until the concentration of nitrogen oxides does not change with the total number of target grids, thereby obtaining multiple encrypted target grids.

10. The method according to claim 9, characterized in that Before performing multiple encryption processes using the encryption criteria until the concentration of nitrogen oxides does not change with the total number of target grids to obtain multiple encrypted target grids, the prediction method further includes: The computational domain of the simulated combustion chamber is first divided to obtain an initial grid; Based on the initial grid, the maximum velocity gradient is calculated using the fluid dynamics model. and the maximum turbulent kinetic energy gradient According to the maximum velocity gradient and the maximum turbulent kinetic energy gradient Performing a second division on the initial grid to obtain a central area, an annular area, and a post-combustion area; Under the second preset condition, the encrypted areas in the central area, the annular area and the post-combustion area are determined.

11. The method according to claim 10, characterized in that The second preset condition includes: The central area and the annular area satisfy: area; The post-combustion zone satisfies: and area.

12. The method according to claim 9, characterized in that The method of performing multiple encryption processes on the encrypted area using the encryption criteria until the concentration of nitrogen oxides does not change with the total number of target grids, thereby obtaining multiple encrypted target grids, including: Use different velocity gradients for the densification areas The encryption rule performs an encryption process, which includes adding a new grid point at the midpoint of each grid line in the encryption area, so that an initial three-dimensional grid becomes 8 new grids.

13. The method according to claim 1, characterized in that The method of calculating the concentration of nitrogen oxides at the outlet of the simulated combustion chamber by using a fluid dynamics model for the plurality of chemical reactors according to the chemical reaction mechanism comprises: Calculating the plurality of chemical reactors using a fluid dynamics model according to a chemical reaction mechanism to obtain physical parameters in a grid, wherein the physical parameters include volume, average pressure, temperature and mass flow rate; According to the physical parameters, using reaction kinetics software to calculate and solve the plurality of chemical reactors, to obtain the components and temperature in each of the chemical reactors; The concentration of nitrogen oxides at the outlet of the simulated combustion chamber is obtained according to the components and temperature in the chemical reactor.

14. A device for predicting nitrogen oxide emissions from a combustion chamber, characterized in that: include: A data acquisition module, used to perform calculations on multiple encrypted target grids using a fluid dynamics model to obtain a parameter field of a simulated combustion chamber, wherein the parameter field includes one or more of a velocity field, a component field, and a temperature field; The first partitioning module is used to divide the simulated combustion chamber into a pure flow zone, a combustion reaction zone and a post-combustion zone according to the flow direction of the simulated combustion chamber airflow and the progress of the combustion reaction; A second partitioning module is used to partition the pure flow area and the combustion reaction area according to the parameter field of the simulated combustion chamber and the first preset condition to obtain a plurality of areas, and use the plurality of areas as a plurality of grid chemical reactors; The calculation module is used to calculate the concentration of nitrogen oxides at the outlet of the simulated combustion chamber by using a fluid dynamics model according to the chemical reaction mechanism of the plurality of chemical reactors.

15. An electronic device for predicting nitrogen oxide emissions from a combustion chamber, characterized in that: include: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the method for predicting combustion chamber nitrogen oxide emissions as claimed in any one of claims 1 to 13 is implemented.

16. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the method for predicting combustion chamber nitrogen oxide emissions as claimed in any one of claims 1 to 13 is implemented.

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