Method for simulating combustion process of combustion cell, storage medium and electronic equipment

Abstract

The invention relates to the technical field of natural gas test blowout, in particular to a method for simulating the combustion process of a combustion cell, a storage medium and electronic equipment, and solves the technical problem that potential safety hazards exist due to the fact that a wing wall is often cracked or part of a cell wall is melted in a traditional masonry combustion cell. The method for simulating the combustion process of the combustion cell comprises the steps that structural parameters of a target combustion cell are obtained, simulation combustion parameters are determined, the structural parameters comprise the size and the structure of the target combustion cell, and the simulation combustion parameters comprise parameters related to the combustion process of the target combustion cell; and constructing a simulation combustion cell according to the structural parameters, simulating the combustion process of the simulation combustion cell according to the simulation combustion parameters, and performing visualization processing to obtain a simulation result.

Description

Technical Field

[0001] The present disclosure relates to the technical field of natural gas test gas release, and in particular to a method, storage medium and electronic equipment for simulating a combustion process of a combustion pool. Background Art

[0002] Gas test and gushing is an essential process in the exploration and production of natural gas. The traditional method of gushing is to build a combustion pool with shale bricks using refractory mortar in a safe area outside the well site, and ignite and burn in the combustion pool to complete the gas test and testing operations. At present, the traditional combustion pool is also mainly used in the oil test and testing operations of unconventional gas reservoirs such as shale gas to gushing and burn the natural gas produced in the formation.

[0003] Since the combustion pool is constructed by traditional refractory mortar masonry shale bricks, after drilling and well blowout test, the traditional masonry combustion pool often has cracks in the wing wall or partial melting of the pool wall, which poses a safety hazard and cannot meet the long-term blowout requirements of the test gas blowout process, seriously affecting the normal operation of the natural gas extraction project. Therefore, it is necessary to select the refractory material for the masonry combustion pool based on the pre-estimated wall temperature to meet the safety requirements of the blowout operation. Summary of the invention

[0004] The purpose of the present disclosure is to provide a method, storage medium and electronic device for simulating the combustion process of a combustion pool, so as to solve the deficiencies of the prior art.

[0005] In order to achieve the above objectives, in a first aspect, the present disclosure provides a method for a true combustion pool combustion process, comprising:

[0006] Acquire structural parameters of a target combustion pool, and determine simulated combustion parameters, wherein the structural parameters include the size and structure of the target combustion pool, and the simulated combustion parameters include parameters involved in the combustion process of the target combustion pool;

[0007] A simulated combustion pool is constructed according to the structural parameters, and the combustion process of the simulated combustion pool is simulated according to the simulated combustion parameters, and visualization processing is performed to obtain simulation results.

[0008] Optionally, constructing a simulated combustion pool according to the structural parameters comprises:

[0009] According to the structural parameters, a lubricator grid, a combustion pool flow field grid and an external area grid are constructed respectively, wherein the density of the lubricator grid is greater than the density of the combustion pool flow field grid, and the density of the combustion pool flow field grid is greater than the density of the external area grid;

[0010] The lubricant preventer grid, the combustion pool flow field grid and the external area grid are combined to obtain a simulated combustion pool.

[0011] Optionally, the simulated combustion parameters include turbulence parameters, thermal radiation parameters, combustion characteristic parameters and reaction rate;

[0012] Determining the simulated combustion parameters includes:

[0013] Determining the relationship between the turbulence parameters during the combustion process in the simulated combustion pool through a turbulence model, wherein the turbulence parameters include flow, heat transfer and chemical reaction;

[0014] Determining the thermal radiation parameters in the heat transfer process in the simulated combustion pool through a thermal radiation model;

[0015] The detailed mechanism of the fuel in the simulated combustion pool is simulated by a methane mechanism model to obtain the combustion characteristic parameters;

[0016] The reaction rate is determined according to the application of the simulated combustion pool.

[0017] Optionally, the simulated combustion parameters include boundary conditions, which are used to limit the initial combustion conditions of the simulated combustion pool, wherein the boundary conditions include target static pressure, target thermal conductivity, target natural gas inlet velocity, target methane concentration, target oxygen concentration and target temperature.

[0018] Optionally, the pressure field of the simulation process is determined as follows:

[0019] According to the initial pressure field, the initial velocity field is determined;

[0020] Correcting the initial pressure field according to the initial velocity field to obtain a corrected pressure field;

[0021] Under the modified pressure field, simulating the combustion process of the simulated combustion pool according to the simulated combustion parameters to obtain a simulation result;

[0022] When the simulation result meets a preset convergence condition, the modified pressure field is used as the target pressure field.

[0023] Optionally, the method for simulating the combustion pool combustion process further comprises:

[0024] When the simulation result does not meet the preset convergence condition, the corrected pressure field is used as the initial stress field of the next operation cycle, and the initial velocity field is determined according to the initial pressure field, the initial pressure field is corrected according to the initial velocity field to obtain a corrected pressure field, and under the corrected pressure field, the combustion process of the simulated combustion pool is simulated according to the simulated combustion parameters to obtain a simulation result, until the simulation result meets the preset convergence condition.

[0025] Optionally, the preset convergence condition includes the following conditions:

[0026] The residual between the simulation result and the actual result satisfies a preset residual threshold;

[0027] The simulation results do not change with iterations during the simulation process;

[0028] The simulation results satisfy the conservation of mass and energy;

[0029] The simulation results do not change with the mesh density.

[0030] Optionally, the method for simulating the combustion pool combustion process further includes: setting a Courant number and a solution limit to restrict the simulation process, wherein the Courant number is used to control the time step format during the simulation process, and the solution limit restricts the density and temperature during the simulation process.

[0031] In a second aspect, the present disclosure provides a non-temporary computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0032] In a third aspect, the present disclosure provides an electronic device, including:

[0033] a memory having a computer program stored thereon;

[0034] A processor is used to execute the computer program in the memory to implement the steps of the method described in the first aspect.

[0035] Through the above technical scheme, the present invention constructs a simulated combustion pool according to structural parameters, simulates the combustion process of the simulated combustion pool according to the simulated combustion parameters, and obtains simulation results, thereby determining the wall temperature distribution state and the position of the high temperature point of the combustion pool according to the simulation results, and screening heat-resistant materials to avoid the wing wall cracking or partial melting of the pool wall that often occurs in the masonry combustion pool, thereby reducing safety hazards and meeting the long-term release requirements of the test gas release process, thereby improving the feasibility of normal operation of the natural gas extraction project.

[0036] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0038] Figure 1 The figure is a flow chart of a method for simulating a combustion pool combustion process according to an exemplary embodiment of the present disclosure.

[0039] Figure 2 is a schematic diagram of a simulated combustion pool according to an exemplary embodiment of the present disclosure.

[0040] Figure 3 is a radial nozzle grid diagram shown according to an exemplary embodiment of the present disclosure.

[0041] Figure 4 The figure is a flow chart showing a method for determining a stress field according to an exemplary embodiment of the present disclosure.

[0042] Figure 5 is a schematic diagram showing a simulation result according to an exemplary embodiment of the present disclosure.

[0043] Figure 6 It is a block diagram of a device for simulating a combustion pool combustion process according to an exemplary embodiment of the present disclosure.

[0044] Figure 7 is a block diagram of an electronic device according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0045] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0046] It should be noted that all actions of acquiring signals, information or data in the present disclosure are carried out in compliance with the relevant data protection laws and policies of the country where the device is located and with the authorization given by the owner of the corresponding device.

[0047] As mentioned in the background technology, the refractory materials for building the combustion pool are selected based on the pre-estimated wall temperature of the combustion pool to meet the safety requirements of the blowdown operation. When the natural gas used for oil testing is blown out, the wall temperature of the combustion pool is relatively high (1000℃-1800℃). The estimation of the wall temperature of the combustion pool is crucial for the selection of refractory materials for building the combustion pool and the subsequent evaluation of thermal shock resistance. The high-temperature measurement methods in the relevant technology include: temperature measuring triangle cone, thermal resistor, thermocouple and infrared temperature measurement technology. Among them, thermal resistor temperature measurement is an element that uses the resistance value of a conductor or semiconductor to change with temperature to measure temperature. It is composed of a thermal resistor body, connecting wires and a display instrument. Thermal resistor thermometers are widely used for temperature measurement in the range of -200℃ to +850℃, and can be divided into standard resistance thermometers and industrial thermal resistors according to the accuracy level.

[0048] Among them, thermocouples use the thermoelectric potential (thermoelectric effect) generated by the temperature difference in the loop formed by connecting two conductors of different components (called thermoelectrodes) at both ends to measure temperature. The temperature range that conventional thermocouples can measure is usually -200℃ to +2500℃. Since the measurement accuracy of thermocouples is the temperature difference, the cold end temperature must be known to calculate the hot end temperature. In order to reduce measurement errors, the reference end of the thermocouple should be moved to a place far away from the heat source and where the ambient temperature is more constant.

[0049] The temperature cone (temperature triangle cone) was invented by Dr. Orton in the United States. It is a high-precision ceramic firing temperature indicator. The temperature cone is a cone carefully configured with more than 100 components. The temperature cone bends in a relatively small temperature range. The final bending position is a measure of the heat absorbed by the temperature cone. It will melt at a certain temperature for a certain period of time, and the triangle cone will melt down to play an indicating role. The effective temperature range of the temperature cone is 565℃ to 2015℃, and the temperature deviation obtained by measuring the bending angle of the temperature cone is within 5℃.

[0050] Infrared temperature measurement technology is based on the black body radiation law and all objects with a temperature above absolute zero are constantly emitting infrared radiation energy to the surrounding space. A black body is an idealized radiator that absorbs radiation energy of all wavelengths, has no energy reflection or transmission, and its surface emissivity is 1. These two together constitute infrared temperature measurement technology. The temperature measurement range is the most important performance indicator of a thermometer. Some thermometer products can reach a range of -50℃ to +3000℃.

[0051] The inventors found that conventional high-temperature thermometers face two major challenges in measuring the wall temperature of the combustion pool when natural gas is released and burned. On the one hand, the combustion pool used for drilling and completion release testing is usually large in size, and it is difficult to predict the distribution of high-temperature areas on the wall of the combustion pool and the location of the highest temperature point before experimental measurement. The direct experimental measurement of the high-temperature thermometer is too labor-intensive and costly. On the other hand, common high-temperature thermometers have certain working condition requirements. For example, the structure of the thermal resistor temperature measuring element is complex and the overall size is large, so the thermal response time is too long, which is not suitable for measuring the temperature transient flow area. The temperature range of the thermocouple cold end compensation wire is specified to be (0~200)℃. In order to reduce the measurement error, the reference end of the thermocouple should be moved to a place far away from the heat source and where the ambient temperature is relatively constant. This limits the use of high-temperature thermometers. In addition, direct experimental measurement has high cost, huge workload, insufficient measurement data, and low wall temperature display.

[0052] In view of this, the present disclosure provides a method, device, storage medium and electronic equipment for a true combustion pool combustion process, which can determine the wall temperature distribution state and the position of high temperature points of the combustion pool, screen heat-resistant materials, and avoid the wing wall cracking or partial melting of the pool wall that often occurs in the masonry combustion pool, thereby reducing safety hazards and meeting the long-term release requirements of the test gas release process, thereby improving the feasibility of normal operation of the natural gas extraction project.

[0053] Figure 1 is a flow chart of a method for simulating a combustion pool combustion process according to an exemplary embodiment of the present disclosure, see Figure 1 The method for simulating the combustion process of the combustion pool may include the following steps:

[0054] In step S11, the structural parameters of the target combustion pool are obtained, and the simulated combustion parameters are determined. The structural parameters include the size and structure of the target combustion pool, and the simulated combustion parameters include the parameters involved in the combustion process of the target combustion pool.

[0055] In step S12, a simulated combustion pool is constructed according to the structural parameters, the combustion process of the simulated combustion pool is simulated according to the simulated combustion parameters, and visualization is performed to obtain simulation results.

[0056] It is worth noting that the simulation result obtained after the calculation converges is just a file. For example, when using the FLUENT solver, the calculation and solution only obtain the *.cas and *.dat source files of the software. This type of file cannot be directly recognized by humans, so it is necessary to visualize the converged file. This process is post-processing.

[0057] It is worth noting that the Tecplot series software is a powerful data analysis and visualization software launched by Tecplot, an American company. It provides a variety of drawing formats, including xy curve graphs, 2-D and 3-D surface drawings in various formats, and 3-D volume drawing formats. Moreover, the software is easy to learn and use, and has a user-friendly interface. Moreover, there is a special data interface for FLUENT software, which can directly read in *.cas and *.dat files, or select the output surface and variables in FLUENT software, and then directly output the Tecplot format document. Tecplot is widely used in post-processing, but in addition, there are EnSight and FieldView; EnSight's icon-based user interface is easy to master and supports most mainstream CAE program interfaces and data formats. FieldView is a post-processing tool dedicated to computational fluid dynamics. Its powerful functions enable engineering and R&D personnel to fully express the flow field and physical behavior in the model, and it has an animated intuitive demonstration of fluid analysis. Therefore, post-processing is performed through FieldView in this embodiment.

[0058] The disclosed embodiment simulates the combustion process of the simulated combustion pool to obtain simulation results, thereby determining the distribution of high-temperature areas on the wall of the combustion pool and the location of the highest temperature point during the natural gas test gas blowing process based on the simulation results, providing an important reference for the optimization of refractory materials for the combustion pool, thereby screening out suitable heat-resistant materials, and avoiding the common occurrence of wing wall cracking or partial melting of the pool wall in the masonry combustion pool, thereby reducing safety hazards and meeting the requirements for long-term blowing during the test gas blowing process, thereby improving the feasibility of normal operation of the natural gas extraction project.

[0059] In order to help those skilled in the art better understand the method of simulating the combustion process of a combustion pool provided by the present invention, the steps involved in the method of simulating the combustion process of a combustion pool are described in detail below with examples.

[0060] In a possible embodiment, constructing a simulated combustion pool according to structural parameters may include:

[0061] According to the structural parameters, the lubricator grid, the burning pool flow field grid and the external area grid are constructed respectively. The density of the lubricator grid is greater than the density of the burning pool flow field grid, and the density of the burning pool flow field grid is greater than the density of the external area grid.

[0062] The blowout preventer grid, the burning pool flow field grid and the external area grid are combined to obtain the simulated burning pool.

[0063] It is worth mentioning that in the field of geometric modeling, in addition to the geometric modeling function of ICEM CFD (The Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics) itself, there are also Solidworks, Pro / E and UG; for example, Solidworks is often used by professional 3D designers. This is a model based on parametric features. The system allows the creation of very detailed curvatures. Moreover, it replaces polygonal modeling and uses dimensional sketches, making resizing easy. Models created by other software can be automatically divided into unstructured grids when imported through ICEM CFD.

[0064] Among them, CAD modeling software can create three types of three-dimensional models: wireframe model, surface model and solid model. The display mode of these three models on the computer is the same, that is, they are displayed in a wireframe structure, but users can use specific commands to make the authenticity of the surface model and the solid model appear. In use, you can choose to use an existing CAD model (extract a fluid domain from a solid domain) or directly create a fluid geometry model; and when establishing a fluid geometry model, you can consider simple geometry, that is, remove unnecessary features that may cause complex grids (chamfers, solder joints, etc.) and use symmetry or periodicity; and you also need to consider whether you need to split the model to obtain boundary conditions or create domains. Therefore, in this embodiment, CAD modeling software is used to construct a simulated combustion pool according to structural parameters.

[0065] For example, the standard combustion pool built by PetroChina Northwest Sichuan Gas Mine Company for oil and gas wells in Sichuan and Chongqing has two configurations, A and B. In this example, the A-type combustion pool is taken as an example. The structural parameters of the A-type combustion pool size include 13.3×4.6×3.5m 3 , set to two layers, the upper wall is 60cm, the lower wall is 100cm, and the result is as follows Figure 2 The simulated burning pool is shown.

[0066] It is worth mentioning that the grid construction process includes: using structured grids, and taking into account the calculation accuracy and grid size, to construct a three-level grid. It mainly involves two aspects: First, in view of the large difference in the size of the pipeline at the entrance of the combustion pool and the entire combustion pool flow field, in order to reduce the amount of grids, reduce the calculation time and ensure the quality of the grid and improve the calculation accuracy, an assembled grid is used, that is, an interface is set on the outside of the pipeline, and the part inside the interface and the part outside the interface are divided into structural grids separately, and then the two parts of the grid are spliced. This not only reduces the difficulty of dividing the grid, reduces the amount of grids, but also improves the quality of the grid. The finest part of the inlet pipeline area uses a 0.5mm grid, and the combustion pool flow field uses a centimeter-level grid size. See Figure 3 . Secondly, since it is necessary to consider the external space area of ​​the combustion pool, for example, to establish an external calculation area of ​​50*50*50m, a relatively coarse grid is used in the external calculation area. In addition, considering the symmetry of the model, the model is divided with the middle section of the combustion pool as the symmetry plane to reduce the division of the grid and the consumption of computer time. The external calculation domain flow field (also known as the far field in the following text) uses a grid size of tens to tens of centimeters.

[0067] In a possible embodiment, the method for simulating the combustion process of a combustion pool may further include: gateway quality detection and gateway independence verification.

[0068] It is worth mentioning that the mesh check of FLUENT provides information on the calculation area, volume statistics, network topology and periodic boundaries. Usually, after the mesh file is read into the FLUENT solver, the correctness of the mesh quality is checked immediately. Mesh errors will cause errors in the iterative solution after the working condition setting. After completing the mesh quality check and substituting it into the subsequent numerical calculation, it is also necessary to compare the calculation results under different numbers of mesh conditions to determine the independence of the results from the mesh, that is, the mesh independence check.

[0069] In a possible embodiment, the simulation combustion parameters include turbulence parameters, heat radiation parameters, combustion characteristic parameters and reaction rate;

[0070] Determining the simulated combustion parameters may include:

[0071] The relationship between the turbulence parameters during the combustion process in the simulated combustion pool is determined through a turbulence model, wherein the turbulence parameters include flow, heat transfer and chemical reaction.

[0072] It is worth noting that combustion involves the interaction of flow, heat transfer and chemical reaction. Natural gas combustion belongs to subsonic turbulence, and it is necessary to select a suitable turbulence model to accurately simulate and solve. There are many turbulent combustion models, such as Spalatrt-Allmaras model, k-ε model, k-ω model, DES model, Reynolds pressure model (RSM) and large eddy model (LES). Different turbulence models contain different calculation equations, so the time for computer solution calculation will also be different. Although the accuracy of the LES model is much higher than that of the k-ε model and k-ω model of the Reynolds average class, it is unbearable to apply it to the calculation of long-term natural gas release and combustion. The k-ε model selected for natural gas combustion in the test gas test is acceptable in terms of calculation time and simulation result accuracy. FLUENT is one of the most commonly used software for simulating fluid flow and heat transfer. FLUENT is used in this embodiment to achieve this.

[0073] The thermal radiation parameters in the heat transfer process in the simulated combustion pool are determined through a thermal radiation model.

[0074] It is worth mentioning that as one of the three major forms of heat transfer, thermal radiation is a common form of heat transfer without the aid of other media, and it is more important at high temperatures. The radiation heat transfer is proportional to the fourth power of the object's temperature. FLUENT provides multiple radiation models, and users need to select the appropriate radiation heat transfer model for specific radiation heat transfer situations. The radiation models in FLUENT include the P1 model, Rosseland model, DTRM model, S2S model, DO model, and MC model. The MC model has the highest accuracy and the highest computational cost compared to other radiation models. The DO model is used to solve combustion-related face-to-face radiation problems, with moderate computational cost and memory requirements. In addition, if the DO or P1 model is selected, the gas absorption coefficient needs to be changed to WSGGM (weighted average gray gas model). The DO model can be used to quickly and accurately select the thermal radiation of the spray flame to the wall of the combustion pool. The default iteration parameter is 10. Increasing this parameter makes it easier to converge but takes more time.

[0075] The detailed mechanism of the fuel in the simulated combustion pool is simulated through the methane mechanism model to obtain the combustion characteristic parameters.

[0076] It is worth noting that in order to more accurately obtain the combustion characteristics of hydrocarbon fuels, it is necessary to couple the kinetic mechanism of fuel combustion with the flow equations for numerical solution. The chemical reaction mechanism used for alternative fuel combustion simulation can be divided into detailed reaction mechanism and general reaction mechanism. The detailed mechanism can well reproduce the combustion characteristics of the fuel, but the detailed mechanism is faced with the challenges of huge computational complexity and strong chemical rigidity when applied to actual chemical-turbulent combustion simulation. The general mechanism can save computational costs well, and the actual chemical-turbulent combustion simulation usually adopts the general reaction mechanism with limited precision. In terms of combustion mechanism, since the vast majority of natural gas is methane, the natural gas mechanism model is replaced by the methane mechanism model during the combustion calculation process. Foreign scholars have proposed many detailed chemical reaction kinetic mechanisms suitable for methane, among which the representative ones include GRI 3.0 mechanism, San Diego mechanism, Princeton mechanism, USC-II mechanism, Aramco Mech 1.3 mechanism, etc. Here, the Princeton methane detailed mechanism, which can accurately describe the combustion characteristics of natural gas and has the smallest mechanism size, is used for the final natural gas combustion mechanism file used in FLUENT simulation, which should include the thermodynamic parameters of the components in the form of 7 parameters. The Princeton methane detailed mechanism includes 21 components and 93 reactions, as shown in Table 1 below.

[0077] Mechanism source Alternative fuels Number of components Number of reactions GRI3.0 C0-C3 53 325 San Diego C0-C3 50 244 Princeton C0-C1 21 93 USC-II C0-C4 111 784 Aramco Mech 1.3 C0-C4 124 766

[0078] Table 1

[0079] The reaction rate is determined according to the application of the simulated combustion pool.

[0080] It is worth noting that FLUENT provides five models for combustion simulation applications. Table 3 lists the main application scenarios of the combustion model and indicates whether it is based on a fast response model or a finite rate model. The combustion model of ANASYS FLUENT (fluid simulation software) is shown in Table 2 below.

[0081]

[0082] Table 2

[0083] It can be seen that FLUENT is suitable for the simulation calculation of subsonic turbulent combustion of natural gas rapid injection. The laminar flamelet model needs to assume that the turbulent flame is a collection of laminar flames, and the internal structure of the laminar flame is not affected by turbulence. The combustion state of a certain point in the flow field can be regarded as the statistical average of the combustion states of multiple laminar flamelets. Laminar flamelets can characterize all particles and temperatures through a small number of variables. The main advantage of the laminar flamelet model is that detailed chemical reaction mechanisms can be introduced through the calculation of laminar flamelets. Here, the detailed mechanism of methane with Princeton 21 components can be used. Since laminar flames can be expressed as a function of the mixture fraction and the scalar dissipation rate, a laminar flame database can be established through a large number of calculations or experiments. As long as the local mixture fraction and scalar dissipation rate can be calculated in turbulence, the corresponding values ​​can be called in the laminar flame database, which can greatly reduce the amount of calculation of turbulent flames.

[0084] It is worth mentioning that the heat transfer involved in the calculation of the combustion pool wall temperature mainly consists of three modes: heat conduction inside the combustion pool wall, heat convection between the combustion pool wall and the environment, and heat radiation of the sprayed flame to the combustion pool wall.

[0085] There is a certain temperature difference between the blocks of the combustion pool, and heat is exchanged through heat conduction. The key to heat conduction calculation lies in the thermal conductivity of the material, which is usually a constant and a function of temperature. The wall material of the combustion pool uses shale bricks with an average thermal conductivity of 0.75w / m·k at room temperature. As the combustion proceeds, the ambient temperature surges, and the thermal conductivity of shale bricks increases at high temperatures.

[0086] Convective heat transfer usually refers to natural convection that does not rely on external forces such as pumps or fans. Forced convection is caused by the existence of external forces, such as forced convection due to changes in external wind pressure. Without considering the wind, the heat convection between the wall of the combustion pool and the environment is treated as natural convection. The key lies in the convection heat transfer coefficient of the material. In FLUENT, there is no need to set the convection heat transfer coefficient separately. Only flow conditions need to be given, such as the boundary conditions of the inlet. Wind can accelerate gas convection. The stronger the wind, not only the faster the convection, but also the positive and negative pressures on the surface of the house, forming a cyclone zone around the building (structure); changes in wind direction will change the direction of gas convection.

[0087] In a possible embodiment, the simulated combustion parameters include boundary conditions, which are used to limit the initial combustion conditions of the simulated combustion pool, wherein the boundary conditions include target static pressure, target thermal conductivity, target natural gas inlet velocity, target methane concentration, target oxygen concentration and target temperature.

[0088] It is worth noting that the wall of the combustion pool is the wall boundary, the small round tube is the methane transportation pipeline (the pipeline area is hollowed out here because the transportation of natural gas in long-distance pipelines is not considered here), and the end face of the pipeline extending into the combustion pool is set as the velocity inlet. The boundary of the external calculation domain, the bottom surface is the wall, and the other surfaces are the pressure outlet boundaries.

[0089] For example, PetroChina's Northwest Sichuan Gas Mine uses standard combustion pools, namely Type A and Type B combustion pools. Take the inlet condition of a Type A quasi-combustion pool as an example: the static pressure is 0 (one standard atmospheric pressure), the component methane comes from the methane transportation pipeline, and the oxygen comes from the natural pressure outlet boundary, with concentrations of 1.00 mol / L and 0.21 mol / L respectively. The initial temperature of the numerical simulation is 15°C at room temperature. The inlet flow rates of Type A and Type B combustion pools are 700,000 cubic meters and 1 million cubic meters per day, respectively, which are converted into inlet flow rates of 255.1 and 178.6 m / s, respectively. See Table 3 below.

[0090]

[0091] Table 3

[0092] In one possible embodiment, see Figure 4 , the pressure field of the simulation process can be determined as follows:

[0093] According to the initial pressure field, the initial velocity field is determined;

[0094] Correcting the initial pressure field according to the initial velocity field to obtain a corrected pressure field;

[0095] Under the corrected pressure field, the combustion process of the simulated combustion pool is simulated according to the simulated combustion parameters to obtain the simulation results;

[0096] When the simulation results meet the preset convergence conditions, the corrected pressure field is used as the target pressure field.

[0097] It is worth noting that FLUENT has two solvers, namely, a pressure-based solver and a density-based solver. The solvers of the two solvers also solve the same object. However, for the research object of the present invention, the result of using the pressure-based solver is more accurate. The pressure-based solver uses momentum and pressure as the main variables. FLUENT provides four pressure-velocity coupling algorithms. That is, SIMPLE algorithm, SIMPLEC algorithm, PISO algorithm and Coupled.

[0098] The SIMPLE algorithm is the most widely used flow field calculation method in engineering practice. Its basic idea is to obtain the velocity field by solving the discrete form of the momentum equation for a given pressure field. Because the pressure is assumed or inaccurate, the velocity field obtained from it generally does not meet the conditions of the continuity equation, so the given pressure field needs to be corrected.

[0099] In a possible embodiment, the method for simulating the combustion process of the combustion pool further includes:

[0100] When the simulation result does not meet the preset convergence condition, the corrected pressure field is used as the initial stress field of the next operation cycle, and the initial velocity field is determined according to the initial pressure field, the initial pressure field is corrected according to the initial velocity field to obtain a corrected pressure field, and under the corrected pressure field, the combustion process of the simulated combustion pool is simulated according to the simulated combustion parameters to obtain a simulation result, until the simulation result meets the preset convergence condition.

[0101] For example, see Figure 4 The SIMPLE algorithm consists of two steps: the first step is to assume a pressure field, and then solve the momentum equation from the predicted pressure field to obtain a velocity field; the second step is to solve the continuity equation with the obtained velocity field, and then correct the pressure field. If the corrected result converges, the result is directly obtained. If it does not converge, the corrected pressure field is returned to perform the next cycle of calculation.

[0102] In a possible embodiment, the preset convergence condition may include the following conditions:

[0103] The residual between the simulation result and the actual result satisfies a preset residual threshold;

[0104] The simulation results do not change with iterations during the simulation process;

[0105] The simulation results satisfy the conservation of mass and energy;

[0106] The simulation results do not change with the mesh density.

[0107] It is worth noting that the calculation in the simulation process is a steady-state calculation. For the steady-state calculation, the convergence criteria are as follows:

[0108] A. The residual of the simulation results meets the requirements. The convergence index of the specific parameters is: the preset residual threshold corresponding to the energy equation is 10 -6 ; The preset residual threshold corresponding to the NOx equation is 10 -6 ; The preset residual threshold corresponding to the radiation equation is 10 -6 ; The preset residual threshold corresponding to the component equation is 10 -5 ; The default residual threshold for other parameters is 10 -4 .

[0109] B. Physical quantities at sensitive locations in the simulation results, such as velocity, temperature, and pressure, do not continue to change as the iteration proceeds.

[0110] C. The physical quantities at the outlet in the simulation results, such as velocity, temperature and pressure, do not continue to change as the iteration proceeds.

[0111] D. Conservation of mass and energy of simulation results.

[0112] E. The simulation results are independent of the grid, that is, for the results obtained using a certain grid, if the grid is encrypted and then calculated again, the results will remain unchanged.

[0113] F. Independence of the treatment of the near-wall region in the simulation results. The use of wall functions may be misunderstood in some cases, such as flow around. In this case, the independence of the calculation results from the wall function or the treatment of the near-wall region should be checked.

[0114] G. Independence of inlet boundary conditions in simulation results.

[0115] In a possible embodiment, the simulation method for simulating the combustion pool combustion process also includes initialization processing.

[0116] It is worth noting that when starting the calculation, an initial value must be set for the flow field, that is, initialization. The closer the initialization value is to the most converged solution, the faster the calculation will be. Otherwise, the calculation will be longer or even non-convergent.

[0117] For example, there are two initialization methods in FLUENT, global initialization and local initialization.

[0118] 1) Global initialization

[0119] The global initialization of the flow field before calculation is set in the Solution Initialization panel. This panel pops up when you perform the Solve / Initialization operation. The initialization steps are as follows.

[0120] ①Set the initial value

[0121] If you want to use the initial values ​​set on a certain area for global initialization, you should first select the area name for which you need to define the initial values ​​in the Compute from drop-down list, and set the values ​​of each variable in the Initial Values ​​option group. The values ​​of the variables in all flow field areas will complete the initialization process based on the set initial values.

[0122] If the average value is used to initialize the flow field and the variables are set in the item group, select all-zones in the Compute from drop-down list. FLUENT will then calculate the initial values ​​based on the values ​​set on the boundaries to complete the initialization of the flow field.

[0123] If you want to change the value of a variable, you can directly enter the new variable value in the corresponding text box.

[0124] ② If a moving grid is used in the calculation, you can decide whether to set the initial value as absolute speed or relative speed by selecting the Absolute (absolute speed) radio option or the Relative to Cell Zone (relative to the grid area) radio option. The default setting is relative speed.

[0125] ③After checking all the initial value settings, you can click the Initialization button to start the initialization of the flow field. If the initialization is restarted during the calculation process, you must confirm with Initialize to overwrite the calculated values ​​with the new initial values.

[0126] The meanings of some buttons in the initialization panel are as follows.

[0127] 1. Click the Initialize button to save the initial value settings and perform initialization calculations.

[0128] 2. Reset button. If there is an error in the initialization process, such as an error in the initial value or using the wrong area as the starting area, you can click this button to restore the initial value to the default value.

[0129] 2) Local initialization

[0130] After completing global initialization, you may need to locally patch the values ​​of some variables. Local patching is set in the Patch dialog box.

[0131] Because local patching does not affect other variables of the flow field, it is also possible to use local patching to change the values ​​of certain variables during the calculation process, thereby artificially intervening in the calculation process.

[0132] The steps for local repair are as follows.

[0133] ① Select the variable name that needs to be patched in the Variable list.

[0134] ② Select the area where the variables to be patched are located in Zones to Patch or Registers to Patch.

[0135] ③If you need to patch the value of the variable to a constant, enter the value of the variable directly in the text box. If you need to define the variable with a pre-set function, you can check the Use Field Function checkbox and select the appropriate field function in the Fick Function list.

[0136] ④ If the variable to be patched is speed, in addition to defining the magnitude of the speed, it is also necessary to define whether the speed is absolute or relative.

[0137] ⑤Click the Patch button to update the flow field data.

[0138] Local patching is usually performed on a certain flow field area, while local patching with a marked area can be used to patch the variable values ​​on a portion of the grid in a certain flow field area. The marked area can be marked with the physical coordinates of the grid, the volume characteristics of the grid, the gradient of the variable, or other parameters. After creating the marked area, the initial value on the marked area can be locally patched.

[0139] In a possible embodiment, the method for simulating the combustion pool combustion process may also include: setting the Courant number and the solution limit to limit the simulation process, wherein the Courant number is used to control the time step format during the simulation process, and the solution limit limits the density and temperature during the simulation process.

[0140] It is worth noting that in FLUENT's coupled solution method, the Courant number (CFL) plays a major role in controlling the time step format. The Courant number is a range defined by linear stability theory, within which the calculation format is stable. Given a Courant number, a time step can be obtained accordingly. The larger the Courant number, the longer the time step and the faster the calculation converges. Therefore, in the calculation, the Courant number is taken as the maximum value as possible within the allowable range. The stability limits of coupled implicit and explicit solvers are different. Explicit solvers have a larger range of restrictions and require a smaller Courant number than implicit solvers.

[0141] For example, taking the Courant number in the coupled explicit format as an example, the range of the Courant number in the explicit format and the implicit format is very different. In the explicit format, the range of the Courant number is very small, while in the implicit format, the range is much larger. In the multi-step format used by FLUENT, it can be considered that the Courant number is stable within a range of less than 2.5. Since the control equation is nonlinear, the value of the Courant number generally does not reach the limit value obtained by linear stability analysis. In the explicit format of the coupled algorithm, the default value set by the system is 1.0. This value can be appropriately enlarged in some two-dimensional problems, but it should not exceed 2.0.

[0142] It is worth noting that the maximum and minimum values ​​of the flow field variables during the calculation process can be set in the SolutionLimits dialog box. Perform the Solve / Controls / Limits operation to pop up the dialog box. Setting the solution variable limits is to avoid non-physical solutions in the calculation, such as density or temperature becoming negative or the solution far exceeding the true value.

[0143] For example, in FLUENT, the daily temperature change rate limit can be set at the same time to avoid negative temperature values ​​due to excessive temperature changes. The default setting for the temperature change rate is 0.2, that is, the temperature change rate cannot exceed 20%.

[0144] For example, by using the above method to simulate the combustion process of the combustion pool, the numerical simulation of the A2 type combustion pool of the Northwest Sichuan Gas Mine of PetroChina under a certain working condition can be obtained as follows: Figure 5 The inner wall temperature distribution diagram is shown.

[0145] In the disclosed embodiments, it is clear that the combustion of natural gas, the object of numerical simulation, is a compressible fluid, and its motion is turbulent. According to the conversion of flow rate and pipe diameter, the gas flow velocity is subsonic flow. Based on whether the physical quantity of the flow changes with time and the time-consuming calculation capacity, steady flow is selected. The distribution of high-temperature areas on the wall of the combustion pool and the location of the highest temperature point during the natural gas test gas release process are obtained through combustion numerical simulation, which provides an important reference for the optimization of refractory materials for the combustion pool, thereby avoiding the problem of inaccurate temperature measurement in the screening process of high-temperature heat-resistant materials.

[0146] Based on the same inventive concept, the present disclosure also provides a device for simulating the combustion process of a combustion pool, see Figure 6 The device for simulating the combustion process of the combustion pool includes an acquisition module 601 and a simulation module 602.

[0147] The acquisition module 601 is used to acquire the structural parameters of the target combustion pool and determine the simulated combustion parameters, the structural parameters include the size and structure of the target combustion pool, and the simulated combustion parameters include the parameters involved in the combustion process of the target combustion pool;

[0148] The simulation module 602 is used to construct a simulated combustion pool according to the structural parameters, simulate the combustion process of the simulated combustion pool according to the simulated combustion parameters, and perform visualization to obtain simulation results.

[0149] The disclosed embodiment simulates the combustion process of the simulated combustion pool to obtain simulation results, thereby determining the distribution of high-temperature areas on the wall of the combustion pool and the location of the highest temperature point during the natural gas test gas blowing process based on the simulation results, providing an important reference for the optimization of refractory materials for the combustion pool, thereby screening out suitable heat-resistant materials, and avoiding the common occurrence of wing wall cracking or partial melting of the pool wall in the masonry combustion pool, thereby reducing safety hazards and meeting the requirements for long-term blowing during the test gas blowing process, thereby improving the feasibility of normal operation of the natural gas extraction project.

[0150] Optionally, the simulation module 602 is used to construct the lubricator grid, the combustion pool flow field grid and the external area grid respectively according to the structural parameters, the density of the lubricator grid is greater than the density of the combustion pool flow field grid, and the density of the combustion pool flow field grid is greater than the density of the external area grid;

[0151] The blowout preventer grid, the burning pool flow field grid and the external area grid are combined to obtain the simulated burning pool.

[0152] Optionally, when the simulated combustion parameters include turbulence parameters, thermal radiation parameters, combustion characteristic parameters and reaction rate, the acquisition module 601 is used to determine the relationship between the turbulence parameters in the combustion process in the simulated combustion pool through a turbulence model, and the turbulence parameters include flow, heat transfer and chemical reaction;

[0153] Determining the thermal radiation parameters in the heat transfer process in the simulated combustion pool through a thermal radiation model;

[0154] The detailed mechanism of the fuel in the simulated combustion pool is simulated by a methane mechanism model to obtain the combustion characteristic parameters;

[0155] The reaction rate is determined according to the application of the simulated combustion pool.

[0156] Optionally, the simulated combustion parameters include boundary conditions, which are used to limit the initial combustion conditions of the simulated combustion pool, wherein the boundary conditions include target static pressure, target thermal conductivity, target natural gas inlet velocity, target methane concentration, target oxygen concentration and target temperature.

[0157] Optionally, the simulation module 602 is used to determine the initial velocity field according to the initial pressure field;

[0158] Correcting the initial pressure field according to the initial velocity field to obtain a corrected pressure field;

[0159] Under the corrected pressure field, the combustion process of the simulated combustion pool is simulated according to the simulated combustion parameters to obtain the simulation results;

[0160] When the simulation results meet the preset convergence conditions, the corrected pressure field is used as the target pressure field.

[0161] Optionally, the simulation module 602 is used to use the corrected pressure field as the initial stress field of the next operation cycle when the simulation result does not meet the preset convergence condition, and to determine the initial velocity field based on the initial pressure field, to correct the initial pressure field based on the initial velocity field to obtain a corrected pressure field, and under the corrected pressure field, to simulate the combustion process of the simulated combustion pool according to the simulated combustion parameters to obtain a simulation result, until the simulation result meets the preset convergence condition.

[0162] Optionally, the preset convergence condition may include the following conditions:

[0163] The residual between the simulation result and the actual result satisfies a preset residual threshold;

[0164] The simulation results do not change with iterations during the simulation process;

[0165] The simulation results satisfy the conservation of mass and energy;

[0166] The simulation results do not change with the mesh density.

[0167] Optionally, the simulation module 602 is further used to set the Courant number and solve the limit to limit the simulation process, wherein the Courant number is used to control the time step format during the simulation process, and the solution limit limits the density and temperature during the simulation process.

[0168] Optionally, the simulation module 602 is also used to visualize the simulation results.

[0169] Regarding the device for simulating the combustion process of the combustion pool in the above embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment of the method, and will not be elaborated here.

[0170] Based on the same inventive concept, the present disclosure also provides an electronic device, including:

[0171] a memory having a computer program stored thereon;

[0172] A processor is used to execute the computer program in the memory to implement the steps of the method for simulating the combustion process of the combustion pool.

[0173] The disclosed embodiment simulates the combustion process of the simulated combustion pool to obtain simulation results, thereby determining the distribution of high-temperature areas on the wall of the combustion pool and the location of the highest temperature point during the natural gas test gas blowing process based on the simulation results, providing an important reference for the optimization of refractory materials for the combustion pool, thereby screening out suitable heat-resistant materials, and avoiding the common occurrence of wing wall cracking or partial melting of the pool wall in the masonry combustion pool, thereby reducing safety hazards and meeting the requirements for long-term blowing during the test gas blowing process, thereby improving the feasibility of normal operation of the natural gas extraction project.

[0174] Figure 7 FIG. 7 is a block diagram of an electronic device 700 according to an exemplary embodiment. Figure 7 As shown, the electronic device 700 may include: a processor 701 and a memory 702. The electronic device 700 may also include one or more of a multimedia component 703, an input / output (I / O) interface 704, and a communication component 705.

[0175] Wherein, processor 701 is used to control the overall operation of the electronic device 700, to complete all or part of the steps in the method of the above-mentioned simulation combustion pool combustion process. Memory 702 is used to store various types of data to support the operation of the electronic device 700, and these data may for example include instructions of any application or method for operating on the electronic device 700, and data related to the application, such as structural parameters, simulation combustion parameters, etc. The memory 702 can be implemented by any type of volatile or non-volatile storage device or their combination, such as static random access memory (Static Random Access Memory, SRAM for short), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, EEPROM for short), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, EPROM for short), programmable read-only memory (Programmable Read-Only Memory, PROM for short), read-only memory (Read-Only Memory, ROM for short), magnetic storage, flash memory, disk or optical disk. Multimedia component 703 may include screen and audio component. The screen may be, for example, a touch screen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signal may be further stored in the memory 702 or sent through the communication component 705. The audio component also includes at least one speaker for outputting audio signals. The I / O interface 704 provides an interface between the processor 701 and other interface modules, and the other interface modules may be keyboards, mice, buttons, etc. These buttons may be virtual buttons or physical buttons. The communication component 705 is used for wired or wireless communication between the electronic device 700 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IOT, eMTC, or other 5G, etc., or a combination of one or more of them, is not limited here. Therefore, the corresponding communication component 705 may include: Wi-Fi module, Bluetooth module, NFC module, etc.

[0176] In an exemplary embodiment, the electronic device 700 can be implemented by one or more application specific integrated circuits (ASIC), digital signal processors (DSP), digital signal processing devices (DSPD), programmable logic devices (PLD), field programmable gate arrays (FPGA), controllers, microcontrollers, microprocessors or other electronic components to execute the above-mentioned method of simulating the combustion process of the combustion pool.

[0177] In another exemplary embodiment, a computer-readable storage medium including program instructions is also provided, and when the program instructions are executed by a processor, the steps of the method for simulating the combustion process of the combustion pool described above are implemented. For example, the computer-readable storage medium can be the memory 702 including the program instructions, and the program instructions can be executed by the processor 701 of the electronic device 700 to complete the method for simulating the combustion process of the combustion pool described above.

[0178] In another exemplary embodiment, a computer program product is also provided. The computer program product includes a computer program executable by a programmable device, and the computer program has a code portion for executing the above-mentioned method of simulating the combustion process of a burning pool when executed by the programmable device.

[0179] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0180] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0181] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for simulating the combustion process of a combustion pool, characterized in that: include: Acquire structural parameters of a target combustion pool, and determine simulated combustion parameters, wherein the structural parameters include the size and structure of the target combustion pool, and the simulated combustion parameters include parameters involved in the combustion process of the target combustion pool; A simulated combustion pool is constructed according to the structural parameters, and the combustion process of the simulated combustion pool is simulated according to the simulated combustion parameters, and visualization processing is performed to obtain simulation results.

2. The method for simulating the combustion process of a combustion pool according to claim 1, characterized in that: The method of constructing a simulated combustion pool according to the structural parameters comprises: According to the structural parameters, a lubricator grid, a combustion pool flow field grid and an external area grid are constructed respectively, wherein the density of the lubricator grid is greater than the density of the combustion pool flow field grid, and the density of the combustion pool flow field grid is greater than the density of the external area grid; The lubricant preventer grid, the combustion pool flow field grid and the external area grid are combined to obtain a simulated combustion pool.

3. The method for simulating the combustion process of a combustion pool according to claim 1, characterized in that: The simulation combustion parameters include turbulence parameters, thermal radiation parameters, combustion characteristic parameters and reaction rate; Determining the simulated combustion parameters includes: Determining the relationship between the turbulence parameters during the combustion process in the simulated combustion pool through a turbulence model, wherein the turbulence parameters include flow, heat transfer and chemical reaction; Determining the thermal radiation parameters in the heat transfer process in the simulated combustion pool through a thermal radiation model; The detailed mechanism of the fuel in the simulated combustion pool is simulated by a methane mechanism model to obtain the combustion characteristic parameters; The reaction rate is determined according to the application of the simulated combustion pool.

4. The method for simulating the combustion process of a combustion pool according to claim 1, characterized in that: The simulated combustion parameters include boundary conditions, which are used to limit the initial combustion conditions of the simulated combustion pool, wherein the boundary conditions include target static pressure, target thermal conductivity, target natural gas inlet velocity, target methane concentration, target oxygen concentration and target temperature.

5. The method for simulating the combustion process of a combustion pool according to any one of claims 1 to 4, characterized in that: The pressure field during the simulation is determined as follows: According to the initial pressure field, the initial velocity field is determined; Correcting the initial pressure field according to the initial velocity field to obtain a corrected pressure field; Under the modified pressure field, simulating the combustion process of the simulated combustion pool according to the simulated combustion parameters to obtain a simulation result; When the simulation result meets a preset convergence condition, the modified pressure field is used as the target pressure field.

6. The method for simulating the combustion process of a combustion pool according to claim 5, characterized in that: The method for simulating the combustion pool combustion process also includes: When the simulation result does not meet the preset convergence condition, the corrected pressure field is used as the initial stress field of the next operation cycle, and the initial velocity field is determined according to the initial pressure field, the initial pressure field is corrected according to the initial velocity field to obtain a corrected pressure field, and under the corrected pressure field, the combustion process of the simulated combustion pool is simulated according to the simulated combustion parameters to obtain a simulation result, until the simulation result meets the preset convergence condition.

7. The method for simulating the combustion process of a combustion pool according to claim 5, characterized in that: The preset convergence conditions include the following conditions: The residual between the simulation result and the actual result satisfies a preset residual threshold; The simulation results do not change with iterations during the simulation process; The simulation results satisfy the conservation of mass and energy; The simulation results do not change with the mesh density.

8. The method for simulating the combustion process of a combustion pool according to claim 1, characterized in that: The method for simulating the combustion pool combustion process also includes: setting the Courant number and the solution limit to restrict the simulation process, wherein the Courant number is used to control the time step format during the simulation process, and the solution limit restricts the density and temperature during the simulation process.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method described in any one of claims 1 to 8 are implemented.

10. An electronic device, characterized in that: include: a memory having a computer program stored thereon; A processor, configured to execute the computer program in the memory to implement the steps of the method according to any one of claims 1 to 8.

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