Gas-solid two-phase flow interphase heat transfer calculation method, system and equipment

Abstract

The invention relates to the technical field of chemical process simulation, in particular to a gas-solid two-phase flow inter-phase heat transfer calculation method, system and equipment, and solves the problem that current accurate fine grid numerical simulation can only be limited to laboratory scale calculation and cannot be used for large-scale calculation through filtering analysis and fitting to obtain a gas-solid two-phase flow inter-phase heat transfer calculation model. In the process of amplifying to the industrial scale, the calculation cost cannot be borne by using fine grid simulation; and meanwhile, the problem that a high-precision mesoscale gas-solid interphase heat transfer model is lacked in coarse grid calculation is solved, and the calculation precision is ensured while the calculation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of chemical process simulation technology, specifically to a method, system, and equipment for calculating heat transfer between gas and solid phases. Background Technology

[0002] Gas-solid fluidized bed reactors have been widely used in the energy and chemical industry due to their excellent mixing, mass transfer and heat transfer performance. Understanding the flow and heat transfer characteristics of gas-solid two-phase flow systems is of great significance for improving the performance of industrial equipment.

[0003] Since mesoscale structures such as particle agglomerates are ubiquitous in gas-solid two-phase flows, these mesoscale inhomogeneous structures directly affect gas-solid flow characteristics and gas-solid contact efficiency, thereby affecting heat transfer, mass transfer, and chemical reaction processes between the gas and solid phases. Traditional uniform models using coarse-grid methods, which are more suitable for large-scale industrial gas-solid heat transfer simulations, cannot account for the influence of mesoscale structures. Actual gas-solid two-phase flows are often accompanied by the formation of mesoscale structures of varying shapes and sizes, such as particle agglomerates and bubbles. The presence of mesoscale or subgrid-scale inhomogeneous structures directly affects gas-solid flow characteristics and the contact efficiency between the gas and solid phases, thus influencing heat transfer, mass transfer, and chemical reaction processes between the two phases. Because particles located in the center of agglomerates have difficulty contacting the airflow outside the agglomerates, the presence of agglomerates significantly reduces the heat and mass transfer characteristics between the gas and particles. Ignoring the influence of inhomogeneous mesoscale structures may lead to significant discrepancies between predicted results and actual reactor performance, failing to meet practical requirements. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for constructing a gas-solid two-phase flow medium-scale heat transfer model, thereby solving the technical problem of inaccurate predictions in current gas-solid two-phase flow medium-scale heat transfer models.

[0005] The solution of the present invention to the above-mentioned technical problems is as follows: A method for calculating heat transfer between phases in a gas-solid two-phase flow includes the following steps: S1. Set the initial gas-solid two-phase calculation parameters; S2. Fine mesh parameters are obtained through CFD-DEM coupled simulation under initial boundary conditions; S3. Process the fine mesh parameters to obtain the coarse mesh filtering parameters; S4. Based on the coarse grid filtration parameters, obtain the correction amount of the gas-solid phase heat transfer coefficient corresponding to the change of solid filtration volume fraction for different dimensionless temperature differences between the gas and solid phases at different filtration scales. S5. Based on the obtained correction amount of the gas-solid phase heat transfer coefficient, fit the mesoscale gas-solid phase heat transfer coefficient correction model corresponding to the filtration scale, solid filtration volume fraction and dimensionless temperature difference between the gas and solid phases.

[0006] Further specifying, step S2 specifically includes: The solid volume fraction of fine mesh was obtained through CFD-DEM coupled simulation under the control of initial boundary conditions and the mass, momentum, and energy conservation equations. Fine mesh solid velocity Fine mesh gas phase gas content Fine mesh solid phase temperature Fine-grid gas phase velocity and fine mesh gas phase temperature ; in, For the fine grid position coordinates, The time variable is used for transient simulation of time.

[0007] Further specifying, step S3 includes the following steps: S3.1, Based on the solid volume fraction of the fine mesh and weight function Solid filtration volume fraction is obtained through spatial filtration. :

[0008]

[0009] in, These are the coordinates of the coarse grid. If the fine grid is outside the coarse grid, then... If the finer grid is within the coarser grid, then , , For coarse mesh volume, For filtering scale; S3.2, Based on the gas phase content of the fine mesh and weight function The gas phase filter holdup is obtained through spatial filtration. :

[0010] S3.3, Based on the gas phase velocity of the fine mesh and weight function The gas phase filtration velocity was obtained by averaging using Favre. :

[0011] Among them, solid phase filtration rate The unit is m / s; S3.4, Based on the solid phase velocity of the fine mesh and weight function The solid-phase filtration rate was obtained by averaging using Favre. :

[0012] Among them, solid phase filtration rate The unit is m / s; S3.5, Based on the fine mesh vapor phase temperature and weight function The gas phase filtration temperature was obtained by averaging using Favre. :

[0013] Among them, solid phase filtration temperature Units are ; S3.6, Based on the solid phase temperature of the fine mesh and weight function The solid-phase filtration temperature was obtained by averaging using Favre. :

[0014] Among them, solid phase filtration temperature Units are .

[0015] Further specifying, step S4 specifically includes: S4.1 Determine the microscopic gas-solid interphase heat transfer coefficient :

[0016]

[0017] in, The effective thermal conductivity in the gas phase, For fine-grid solid volume fraction, Let be the Nusselt number of the particle. The particle diameter is Let be the Reynolds number of the particle. For Prandtl numbers, For fine-grid gas phase gas holdup; S4.2, Define the correction amount for the gas-solid phase heat transfer coefficient. :

[0018]

[0019] In the formula, The heat transfer coefficient between the gas and solid phases at the filtration scale; This represents the volume fraction of solids filtered. This refers to the gas phase filtration rate. For solid-phase filtration rate, This refers to the gas phase filtration temperature. This is the solid-phase filtration temperature. This is the solid-state temperature of the fine mesh. This refers to the gas phase temperature of the fine mesh. S4.3 Constructing a coarse mesh: Dimensionless gas-solid phase temperature difference between the mesh of interest and the surrounding meshes. :

[0020]

[0021]

[0022] in, The focus is on the solid-phase filtration temperature of the mesh. The focus is on the gas phase filtration temperature of the grid. It is the Favre average solid-phase filtration temperature of the surrounding grid. It is the Favre average vapor phase filtration temperature of the surrounding grid; S4.4 Set multiple filtration scales and obtain the correction amount of the gas-solid phase heat transfer coefficient corresponding to the change of solid filtration volume fraction under different dimensionless temperature differences between the gas and solid phases for each filtration scale.

[0023] Further specifying, step S4.4 specifically includes: Set the data collection interval, data collection time, and multiple filtering scales; Choose the first filtering scale; During the data acquisition time, the corresponding correction amount of the gas-solid phase heat transfer coefficient is obtained according to the data acquisition interval; Record the dimensionless temperature difference between the gas and solid phases and the volume fraction of solid filtration corresponding to different corrections for the gas-solid phase heat transfer coefficients. Based on the range of solid filtration volume fraction variation, multiple sequentially connected solid filtration volume fraction calculation ranges are set. Under the same dimensionless temperature difference between the gas and solid phases, the average value of all gas-solid phase heat transfer coefficient corrections corresponding to each solid filtration volume fraction calculation interval is taken as the final gas-solid phase heat transfer coefficient correction corresponding to the current solid filtration volume fraction. Determine the correction amount of the final gas-solid phase heat transfer coefficient corresponding to the solid filtration volume fraction under different dimensionless temperature differences between the gas and solid phases; Select the next filtration scale and determine the final gas-solid phase heat transfer coefficient correction amount corresponding to the solid filtration volume fraction under different dimensionless temperature differences between the gas and solid phases at the current filtration scale. Until all filtration scales are completed, the correction amount of the final gas-solid phase heat transfer coefficient corresponding to different solid filtration volume fractions under different dimensionless temperature differences between the gas and solid phases is determined.

[0024] Further specifying, the data acquisition time is the [number]th [time]. arrive The data collection interval is every [number] days within the data collection period. The Middle , No. and the , denoted as the relaxation time of the particle.

[0025] Further specifying, step S6 specifically includes: Based on the obtained final gas-solid phase heat transfer coefficient correction, a system containing solid filtration volume fraction is constructed. dimensionless temperature difference between gas and solid phases and dimensionless filtration scale Mesoscale gas-solid phase heat transfer coefficient correction model : When satisfied hour:

[0026]

[0027] When satisfied hour:

[0028]

[0029] in, , , , , , , , , , , , ; When satisfied hour:

[0030]

[0031] When satisfied hour, .

[0032] A modified model for the interphase heat transfer coefficient of gas-solid flow at a mesoscale is obtained by the above-mentioned calculation method for interphase heat transfer in gas-solid two-phase flow.

[0033] A gas-solid two-phase flow interphase heat transfer calculation system, used to implement the above-mentioned gas-solid two-phase flow interphase heat transfer calculation method, includes: The gas-solid parameter setting unit is used to set the initial gas-solid two-phase calculation parameters; Fine mesh parameter calculation unit, used to obtain fine mesh parameters through CFD-DEM coupled simulation under initial boundary conditions; The coarse mesh filtering parameter calculation unit is used to process the fine mesh parameters to obtain the coarse mesh filtering parameters. The three-parameter correction acquisition unit is used to obtain the correction amount of the gas-solid phase heat transfer coefficient corresponding to the change of the dimensionless temperature difference between the gas and solid phases with the solid filtration volume fraction under different filtration scales, based on the coarse grid filtration parameters. The gas-solid two-phase flow interphase heat transfer calculation unit is used to fit a corrected model of the mesoscale gas-solid interphase heat transfer coefficient corresponding to the filtration scale, solid filtration volume fraction, and dimensionless temperature difference between the gas and solid phases, based on the obtained correction amount of the gas-solid interphase heat transfer coefficient.

[0034] A gas-solid two-phase flow interphase heat transfer calculation device includes a non-volatile storage medium and a central processing unit. The non-volatile storage medium stores executable code. When the central processing unit executes the executable code, it implements the gas-solid two-phase flow interphase heat transfer calculation method as described above.

[0035] The beneficial effects of this invention are as follows: 1. This invention obtains a coarse-grid, mesoscale gas-solid two-phase heat transfer model through filtering analysis and fitting. This solves the problem that current accurate fine-grid numerical simulations are limited to laboratory-scale calculations, and the computational cost of using fine-grid simulations is prohibitive when scaling up to industrial scales. At the same time, it solves the problem of lacking a high-precision mesoscale gas-solid interphase heat transfer model in coarse-grid calculations, improving computational efficiency while ensuring computational accuracy.

[0036] 2. The mesoscale gas-solid phase heat transfer coefficient correction model constructed in this invention combines the dimensionless temperature difference between the gas and solid phases with the environmental temperature difference normalization to eliminate dependence and solve the temperature range dependence problem; at the same time, it combines three parameters—solid filtration volume fraction, dimensionless temperature difference between the gas and solid phases, and dimensionless filtration scale—to construct a unified model that considers the influence of temperature difference, thus significantly improving accuracy; this invention can shorten the calculation time, simulate heat transfer more accurately, and meet the needs of practical use. Attached Figure Description

[0037] Figure 1 This is a step diagram illustrating the method for constructing a gas-solid two-phase flow medium-scale heat transfer model for the reactor according to the present invention. Figure 2 For the present invention in filtration scale A graph showing the relationship between the correction amount of the gas-solid phase heat transfer coefficient and the dimensionless temperature difference between the gas and solid phases at different solid filtration volume fractions. Figure 3 For the present invention in terms of filtration scale A graph showing the relationship between the correction amount of the gas-solid phase heat transfer coefficient and the dimensionless temperature difference between the gas and solid phases at different solid filtration volume fractions. Figure 4 For the present invention in filtration scale A graph showing the relationship between the correction amount of the gas-solid phase heat transfer coefficient and the gas-solid filtration temperature difference under different solid filtration volume fractions. Figure 5 For the present invention in filtration scale A graph showing the relationship between the correction amount of the gas-solid phase heat transfer coefficient and the gas-solid filtration temperature difference under different solid filtration volume fractions. Figure 6 The filtration scale of this invention is The corresponding fitting performance plot; Figure 7 Different filtration scales obtained in this invention and The Pearson correlation coefficient and the coefficient obtained from the heat source term method and Pearson correlation coefficient plot; Figure 8 Different filtration scales obtained in this invention and coefficient of determination and obtained according to the heat source term method and The coefficient of determination diagram; Figure 9 For different filtration scales of the present invention and The probability density distribution function of the relative error between them is plotted. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] Example 1 This embodiment provides a method for constructing a corrected model for the heat transfer coefficient between gas and solid phases at a mesoscale, including the following steps: S1. Set the initial gas-solid two-phase calculation parameters; S2. Fine mesh parameters are obtained through CFD-DEM coupled simulation under initial boundary conditions; S3. Process the fine mesh parameters to obtain the coarse mesh filtering parameters; S4. Based on the coarse grid filtration parameters, obtain the correction amount of the gas-solid phase heat transfer coefficient corresponding to the change of solid filtration volume fraction for different dimensionless temperature differences between the gas and solid phases at different filtration scales. S5. Based on the obtained correction amount of the gas-solid phase heat transfer coefficient, fit the mesoscale gas-solid phase heat transfer coefficient correction model corresponding to the filtration scale, solid filtration volume fraction and dimensionless temperature difference between the gas and solid phases.

[0040] To further explain, step S2 specifically involves: The solid volume fraction of fine mesh was obtained through CFD-DEM coupled simulation under the control of initial boundary conditions and the mass, momentum, and energy conservation equations. Fine mesh solid phase velocity Fine mesh gas phase gas content Fine mesh solid phase temperature Fine-grid gas phase velocity and fine mesh gas phase temperature ; in, For the fine grid position coordinates, The time variable is used for transient simulation of time.

[0041] To further explain, step S3 includes the following steps: S3.1, Based on the solid volume fraction of the fine mesh and weight function Solid filtration volume fraction is obtained through spatial filtration. :

[0042]

[0043] in, These are the coordinates of the coarse grid. If the fine grid is outside the coarse grid, then... If the finer grid is within the coarser grid, then , , For coarse mesh volume, For filtering scale; S3.2, Based on the gas phase content of the fine mesh and weight function The gas phase filter holdup is obtained through spatial filtration. :

[0044] S3.3, Based on the gas phase velocity of the fine mesh and weight function The gas phase filtration velocity was obtained by averaging using Favre. :

[0045] Among them, solid phase filtration rate The unit is m / s; S3.4, Based on the solid phase velocity of the fine mesh and weight function The solid-phase filtration rate was obtained by averaging using Favre. :

[0046] Among them, solid phase filtration rate The unit is m / s; S3.5, Based on the fine mesh vapor phase temperature and weight function The gas phase filtration temperature was obtained by averaging using Favre. :

[0047] Among them, solid phase filtration temperature Units are ; S3.6, Based on the solid phase temperature of the fine mesh and weight function The solid-phase filtration temperature was obtained by averaging using Favre. :

[0048] Among them, solid phase filtration temperature Units are .

[0049] To further explain, step S4 specifically involves: S4.1 Determine the microscopic gas-solid interphase heat transfer coefficient :

[0050]

[0051] in, The effective thermal conductivity in the gas phase, For fine-grid solid volume fraction, Let be the Nusselt number of the particle. The particle diameter is Let be the Reynolds number of the particle. For Prandtl numbers, For fine-grid gas phase gas holdup; S4.2, Define the correction amount for the gas-solid phase heat transfer coefficient. :

[0052]

[0053] In the formula, The heat transfer coefficient between the gas and solid phases at the filtration scale; This represents the volume fraction of solids filtered. This refers to the gas phase filtration rate. For solid-phase filtration rate, This refers to the gas phase filtration temperature. This is the solid-phase filtration temperature. This is the solid-state temperature of the fine mesh. This refers to the gas phase temperature of the fine mesh. S4.3 Constructing a coarse mesh: Dimensionless gas-solid phase temperature difference between the mesh of interest and the surrounding meshes. :

[0054]

[0055]

[0056] in, The focus is on the solid-phase filtration temperature of the mesh. The focus is on the gas phase filtration temperature of the grid. It is the Favre average solid-phase filtration temperature of the surrounding grid. It is the Favre average vapor phase filtration temperature of the surrounding grid; S4.4 Set multiple filtration scales and obtain the correction amount of the gas-solid phase heat transfer coefficient corresponding to the change of solid filtration volume fraction under different dimensionless temperature differences between the gas and solid phases for each filtration scale.

[0057] To further explain, step S4.4 specifically involves: Set the data collection interval, data collection time, and multiple filtering scales; The data collection time is the [number]th [time]. arrive The data collection interval is every [number] days within the data collection period. The Middle , No. and the , denoted as the relaxation time of the particle.

[0058] Choose the first filtering scale; During the data acquisition time, the corresponding correction amount of the gas-solid phase heat transfer coefficient is obtained according to the data acquisition interval; Record the dimensionless temperature difference between the gas and solid phases and the volume fraction of solid filtration corresponding to different corrections for the gas-solid phase heat transfer coefficients. The corresponding heat transfer can be directly obtained using the fine mesh parameters. The heat transfer corresponding to the fine mesh is the actual heat transfer corresponding to the coarse mesh. Therefore, in order to obtain the relationship between the correction amount of the gas-solid phase heat transfer coefficient and the dimensionless temperature difference and solid filtration volume fraction of the gas-solid phase, the dimensionless temperature difference and solid filtration volume fraction of the gas-solid phase corresponding to different correction amounts of the gas-solid phase heat transfer coefficient are obtained respectively.

[0059] Based on the range of solid filtration volume fraction variation, multiple sequentially connected solid filtration volume fraction calculation ranges are set. Under the same dimensionless temperature difference between the gas and solid phases, the average value of all gas-solid phase heat transfer coefficient corrections corresponding to each solid filtration volume fraction calculation interval is taken as the final gas-solid phase heat transfer coefficient correction corresponding to the current solid filtration volume fraction. Since the heat transfer at different locations differs for the same dimensionless temperature difference between the gas and solid phases and the same solid filtration volume fraction, the corresponding corrections for the gas-solid phase heat transfer coefficient will also differ. To avoid multiple dependent variables under the same parameters, it is preferable to divide the solid filtration volume fraction variation range into multiple solid filtration volume fraction calculation intervals. For example, the solid filtration volume fraction variation range of 0.05~0.55 is divided into 5 solid filtration volume fraction calculation intervals. The corrections for all gas-solid phase heat transfer coefficients in the calculation interval of 0.05~0.15 are averaged to obtain the final gas-solid phase heat transfer coefficient correction when the solid filtration volume fraction is 0.1. The corrections for all gas-solid phase heat transfer coefficients in the calculation interval of 0.15~0.25 are averaged to obtain the final gas-solid phase heat transfer coefficient correction when the solid filtration volume fraction is 0.2. In this way, the final gas-solid phase heat transfer coefficient corrections for solid filtration volume fractions of 0.1, 0.2, 0.3, 0.4, and 0.5 are obtained respectively.

[0060] Determine the correction amount of the final gas-solid phase heat transfer coefficient corresponding to the solid filtration volume fraction under different dimensionless temperature differences between the gas and solid phases; The correction amount of the final gas-solid phase heat transfer coefficient corresponding to different solid filtration volume fractions under the same dimensionless temperature difference between the gas and solid phases is calculated. Then, the correction amount of the final gas-solid phase heat transfer coefficient corresponding to different solid filtration volume fractions under other dimensionless temperature differences between the gas and solid phases is calculated. Finally, the correction amount of the final gas-solid phase heat transfer coefficient corresponding to different solid filtration volume fractions under different dimensionless temperature differences between the gas and solid phases is obtained under the current filtration scale.

[0061] Select the next filtration scale and determine the final gas-solid phase heat transfer coefficient correction amount corresponding to the solid filtration volume fraction under different dimensionless temperature differences between the gas and solid phases at the current filtration scale. Until all filtration scales are completed, the correction amount of the final gas-solid phase heat transfer coefficient corresponding to different solid filtration volume fractions under different dimensionless temperature differences between the gas and solid phases is determined.

[0062] To further explain, step S6 specifically involves: Based on the obtained final gas-solid phase heat transfer coefficient correction, a system containing solid filtration volume fraction is constructed. dimensionless temperature difference between gas and solid phases and dimensionless filtration scale Mesoscale gas-solid phase heat transfer coefficient correction model : When satisfied hour:

[0063]

[0064] When satisfied hour:

[0065]

[0066] in, , , , , , , , , , , , ; When satisfied hour:

[0067]

[0068] When satisfied hour, .

[0069] Specifically, to illustrate the dimensionless gas-solid filtration temperature difference The classification effect of Q is assessed by filtering the data at different solid volume fractions. The solid filtration volume fraction is calculated by classifying and averaging within the dimensionless gas-solid filtration temperature difference range. The classification interval is 0.005, and the dimensionless temperature difference between the gas and solid phases is [missing value]. The classification interval is 0.01.

[0070] Different solid filtration volume fractions The following is obtained through calculation using fine mesh parameters. That is, the true value, and the dimensionless temperature difference between the gas and solid phases. Relationship, Figure 2 Filtering scale The corresponding result at that time Figure 3 Filtering scale The corresponding result at that time.

[0071] pass Figure 2 and Figure 3 It can be seen that the dimensionless temperature difference between the gas and solid phases... right It has excellent classification ability, with the dimensionless temperature difference between the gas and solid phases. The increase, The value also continues to increase, and this pattern persists as the filtering scale increases.

[0072] To visually compare the dimensionless temperature difference between the gas and solid phases and the temperature difference during gas-solid filtration using a content-dimension dimensionality measurement... The effect of classification is to determine the content, gas-solid filtration, and temperature difference. right The classification effect is drawn on Figure 4 and Figure 5 middle.

[0073] Combination Figures 2-5 dimensionless temperature difference between gas and solid phases right The classification effect is significantly better than that of content-based gas-solid filtration temperature difference. Especially when the filtration scale is small, such as Figure 2 and Figure 4 As shown, this demonstrates the use of a dimensionless temperature difference between the gas and solid phases. Replacement of content dimensions, gas-solid filtration, temperature difference Come to Modeling would be more effective.

[0074] in addition Figure 5 It also shows the content of gas-solid filtration temperature difference. The range is significantly wider than the dimensionless temperature difference between the gas and solid phases. The range, therefore, due to the dimensionless temperature difference between the gas and solid phases. It is a dimensionless quantity, and its range is relatively stable. The dimensionless gas-solid phase filtration temperature difference is used as an index quantity. Modeling is necessary to meet the requirements.

[0075] To further explain, a method based on heat source terms is used to construct a solid filtration volume fraction. dimensionless temperature difference between gas and solid phases and dimensionless filtration scale A three-parameter mesoscale gas-solid phase heat transfer coefficient correction model was used for evaluation, and corresponding fitting performance diagrams were obtained at different filtration scales. The values ​​are respectively , , , , and hour, and The Pearson correlation coefficients were 0.822, 0.964, 0.987, 0.989, 0.992, and 0.992, respectively, based on the filter scale. For example, Figure 6 As shown.

[0076] Obtaining different filtering scales and The Pearson correlation coefficient and the coefficient obtained from the heat source term method and The Pearson correlation coefficient, such as Figure 7 As shown; via Figure 7 Able to see and The Pearson correlation coefficient increases with the increase of the filtering scale, and is superior to existing methods in all aspects.

[0077] Obtaining different filtering scales and coefficient of determination and obtained according to the heat source term method and coefficient of determination ,like Figure 8 As shown; via Figure 8 Able to see and coefficient of determination The efficiency increases with the size of the filter, and is superior to existing methods.

[0078] When obtaining different filter scales and The probability density distribution function PDF of the relative error between them, such as Figure 9 As shown; via Figure 9 Able to see and The size of the filter decreases as the filter size increases, and the distribution also gradually narrows.

[0079] In summary, the mesoscale gas-solid phase heat transfer coefficient correction model constructed in this invention is superior to the existing technology and can be applied to coarse grid heat transfer calculations for gas-solid two-phase flows with a grid size of less than or equal to 40 times the particle diameter. The model constructed in this paper can theoretically be applied to the heat transfer simulation of industrial fluidized bed reactors, meeting practical needs.

[0080] This embodiment also provides a method for calculating interphase heat transfer in gas-solid two-phase flow. The method obtains the interphase heat transfer coefficient of gas-solid flow based on the constructed modified model of the interphase heat transfer coefficient of gas-solid flow, and then performs interphase heat transfer calculation of gas-solid two-phase flow based on the interphase heat transfer coefficient of gas-solid flow.

[0081] Example 2 This embodiment provides a gas-solid two-phase flow interphase heat transfer calculation system to implement the gas-solid two-phase flow interphase heat transfer calculation method described in Embodiment 1, including: The gas-solid parameter setting unit is used to set the initial gas-solid two-phase calculation parameters; Fine mesh parameter calculation unit, used to obtain fine mesh parameters through CFD-DEM coupled simulation under initial boundary conditions; The coarse mesh filtering parameter calculation unit is used to process the fine mesh parameters to obtain the coarse mesh filtering parameters. The three-parameter correction acquisition unit is used to obtain the correction amount of the gas-solid phase heat transfer coefficient corresponding to the change of the dimensionless temperature difference between the gas and solid phases with the solid filtration volume fraction under different filtration scales, based on the coarse grid filtration parameters. The gas-solid two-phase flow interphase heat transfer calculation unit is used to fit a corrected model of the mesoscale gas-solid interphase heat transfer coefficient corresponding to the filtration scale, solid filtration volume fraction, and dimensionless temperature difference between the gas and solid phases, based on the obtained correction amount of the gas-solid interphase heat transfer coefficient.

[0082] Example 3 This embodiment provides a hydropower unit active power control device, including a non-volatile storage medium and a central processing unit. The non-volatile storage medium stores executable code. When the central processing unit executes the executable code, it implements the hydropower unit active power control method as described in Embodiment 1.

[0083] This embodiment also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the gas-solid two-phase flow interphase heat transfer calculation method described in Embodiment 1.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for calculating heat transfer between phases in a gas-solid two-phase flow, characterized in that, Includes the following steps: S1. Set the initial gas-solid two-phase calculation parameters; S2. Fine mesh parameters are obtained through CFD-DEM coupled simulation under initial boundary conditions; S3. Process the fine mesh parameters to obtain the coarse mesh filtering parameters; S4. Based on the coarse grid filtration parameters, obtain the correction amount of the gas-solid phase heat transfer coefficient corresponding to the change of solid filtration volume fraction for different dimensionless temperature differences between the gas and solid phases at different filtration scales. S5. Based on the obtained correction amount of the gas-solid phase heat transfer coefficient, fit the mesoscale gas-solid phase heat transfer coefficient correction model corresponding to the filtration scale, solid filtration volume fraction and dimensionless temperature difference between the gas and solid phases.

2. The method for calculating heat transfer between phases in a gas-solid two-phase flow according to claim 1, characterized in that, Step S2 specifically involves: The solid volume fraction of fine mesh was obtained through CFD-DEM coupled simulation under the control of initial boundary conditions and the mass, momentum, and energy conservation equations. Fine mesh solid velocity Fine mesh gas phase gas content Fine mesh solid phase temperature Fine-grid gas phase velocity and fine mesh gas phase temperature ; in, For the fine grid position coordinates, The time variable is used for transient simulation of time.

3. The method for calculating heat transfer between phases in a gas-solid two-phase flow according to claim 2, characterized in that, Step S3 includes the following steps: S3.1, Based on the solid volume fraction of the fine mesh and weight function Solid filtration volume fraction is obtained through spatial filtration. : in, These are the coordinates of the coarse grid. If the fine grid is outside the coarse grid, then... If the finer grid is within the coarser grid, then , , For coarse mesh volume, For filtering scale; S3.2, Based on the gas phase content of the fine mesh and weight function The gas phase filter holdup is obtained through spatial filtration. : S3.3, Based on the gas phase velocity of the fine mesh and weight function The gas phase filtration velocity was obtained by averaging using Favre. : Among them, solid phase filtration rate The unit is m / s; S3.4, Based on the solid phase velocity of the fine mesh and weight function The solid-phase filtration rate was obtained by averaging using Favre. : Among them, solid phase filtration rate The unit is m / s; S3.5, Based on the fine mesh vapor phase temperature and weight function The gas phase filtration temperature was obtained by averaging using Favre. : Among them, solid phase filtration temperature Units are ; S3.6, Based on the solid phase temperature of the fine mesh and weight function The solid-phase filtration temperature was obtained by averaging using Favre. : Among them, solid phase filtration temperature Units are .

4. The method for calculating heat transfer between phases in a gas-solid two-phase flow according to claim 3, characterized in that, Step S4 specifically involves: S4.1 Determine the microscopic gas-solid interphase heat transfer coefficient : in, The effective thermal conductivity in the gas phase, For fine-grid solid volume fraction, Let be the Nusselt number of the particle. The particle diameter is Let be the Reynolds number of the particle. For Prandtl numbers, For fine-grid gas phase gas holdup; S4.2, Define the correction amount for the gas-solid phase heat transfer coefficient. : In the formula, The heat transfer coefficient between the gas and solid phases at the filtration scale; This represents the volume fraction of solids filtered. For gas phase filtration rate, For solid-phase filtration rate, This refers to the gas phase filtration temperature. This is the solid-phase filtration temperature. This is the solid-state temperature of the fine mesh. This refers to the gas phase temperature of the fine mesh. S4.3 Constructing a coarse mesh: Dimensionless gas-solid phase temperature difference between the mesh of interest and the surrounding meshes. : in, The focus is on the solid-phase filtration temperature of the mesh. The focus is on the gas phase filtration temperature of the grid. It is the Favre average solid-phase filtration temperature of the surrounding grid. It is the Favre average vapor phase filtration temperature of the surrounding grid; S4.4 Set multiple filtration scales and obtain the correction amount of the gas-solid phase heat transfer coefficient corresponding to the change of solid filtration volume fraction under different dimensionless temperature differences between the gas and solid phases for each filtration scale.

5. The method for calculating heat transfer between phases in a gas-solid two-phase flow according to claim 4, characterized in that, Step S4.4 specifically includes: Set the data collection interval, data collection time, and multiple filtering scales; Choose the first filtering scale; During the data acquisition time, the corresponding correction amount of the gas-solid phase heat transfer coefficient is obtained according to the data acquisition interval; Record the dimensionless temperature difference between the gas and solid phases and the volume fraction of solid filtration corresponding to different corrections for the gas-solid phase heat transfer coefficients. Based on the range of solid filtration volume fraction variation, multiple sequentially connected solid filtration volume fraction calculation ranges are set. Under the same dimensionless temperature difference between the gas and solid phases, the average value of all gas-solid phase heat transfer coefficient corrections corresponding to each solid filtration volume fraction calculation interval is taken as the final gas-solid phase heat transfer coefficient correction corresponding to the current solid filtration volume fraction. Determine the correction amount of the final gas-solid phase heat transfer coefficient corresponding to the solid filtration volume fraction under different dimensionless temperature differences between the gas and solid phases; Select the next filtration scale and determine the final gas-solid phase heat transfer coefficient correction amount corresponding to the solid filtration volume fraction under different dimensionless temperature differences between the gas and solid phases at the current filtration scale. Until all filtration scales are completed, the correction amount of the final gas-solid phase heat transfer coefficient corresponding to different solid filtration volume fractions under different dimensionless temperature differences between the gas and solid phases is determined.

6. The method for calculating heat transfer between phases in a gas-solid two-phase flow according to claim 5, characterized in that, The data collection time is the [number]. arrive The data collection interval is each [number] data collection interval within the data collection time. The Middle , No. and the , denoted as the relaxation time of the particle.

7. The method for calculating heat transfer between phases in a gas-solid two-phase flow according to claim 5, characterized in that, Step S6 specifically involves: Based on the obtained final gas-solid phase heat transfer coefficient correction, a system containing solid filtration volume fraction is constructed. dimensionless temperature difference between gas and solid phases and dimensionless filtration scale Mesoscale gas-solid phase heat transfer coefficient correction model : When satisfied hour: When satisfied hour: in, , , , , , , , , , , , ; When satisfied hour: When satisfied hour, .

8. A mesoscale gas-solid phase heat transfer coefficient correction model, characterized in that, The heat transfer calculation method for gas-solid two-phase flow as described in any one of claims 1 to 7 is used.

9. A gas-solid two-phase flow interphase heat transfer calculation system, characterized in that, The method for calculating interphase heat transfer in gas-solid two-phase flow according to any one of claims 1 to 7 includes: The gas-solid parameter setting unit is used to set the initial gas-solid two-phase calculation parameters; Fine mesh parameter calculation unit, used to obtain fine mesh parameters through CFD-DEM coupled simulation under initial boundary conditions; The coarse mesh filtering parameter calculation unit is used to process the fine mesh parameters to obtain the coarse mesh filtering parameters. The three-parameter correction acquisition unit is used to obtain the correction amount of the gas-solid phase heat transfer coefficient corresponding to the change of the dimensionless temperature difference between the gas and solid phases with the solid filtration volume fraction under different filtration scales, based on the coarse grid filtration parameters. The gas-solid two-phase flow interphase heat transfer calculation unit is used to fit a corrected model of the mesoscale gas-solid interphase heat transfer coefficient corresponding to the filtration scale, solid filtration volume fraction, and dimensionless temperature difference between the gas and solid phases, based on the obtained correction amount of the gas-solid interphase heat transfer coefficient.

10. A gas-solid two-phase flow interphase heat transfer calculation device, characterized in that, The system includes a non-volatile storage medium and a central processing unit (CPU). The non-volatile storage medium stores executable code. When the CPU executes the executable code, it implements the gas-solid two-phase flow interphase heat transfer calculation method as described in any one of claims 1 to 7.

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