CN-122021458-A - Molten steel temperature field calculation method and related device based on thermal power balance and flow field characteristics

CN122021458ACN 122021458 ACN122021458 ACN 122021458ACN-122021458-A

Abstract

The application discloses a molten steel temperature field calculation method based on thermal power balance and flow field characteristics and a related device, and relates to the technical field of ferrous metallurgy continuous casting process control, wherein the method comprises the steps of determining a deviation correction coefficient according to a blank drawing speed at the current moment and a casting blank section size, correcting an enthalpy loss distribution function, obtaining a corrected enthalpy loss distribution function at the current moment, and determining a flow field correction source item at the current moment by combining the thermal balance correction enthalpy loss coefficient at the current moment; the method comprises the steps of calculating a heat conduction item at the current moment according to the temperature field distribution at the current moment, calculating a boundary heat flow item at the current moment according to the boundary condition at the current moment, correcting a source item based on a flow field, combining the heat conduction item and the boundary heat flow item at the current moment, updating enthalpy values of all nodes at the current moment, obtaining the temperature field distribution at the next moment through table lookup interpolation, and performing time stepping to the next moment and circulation until pouring is finished. The application improves the calculation precision of the molten steel temperature field in the crystallizer.

Inventors

LIAN TIANLONG
DUAN HUAMEI
WANG WENXUE
ZENG JING
LONG MUJUN
CHEN DENGFU

Assignees

重庆大学
中国重型机械研究院股份公司

Dates

Publication Date: 20260512
Application Date: 20260331

Claims (10)

1. The method for calculating the molten steel temperature field based on the thermal power balance and the flow field characteristics is characterized by comprising the following steps of: Acquiring field data at the current moment, wherein the field data comprise a blank pulling speed, boundary conditions, a crystallizer water inlet and outlet temperature and a crystallizer copper plate cooling water flow; Determining a deviation correction coefficient of the current moment according to the blank drawing speed of the current moment and the preset casting blank section size, and correcting a pre-constructed enthalpy loss distribution function by using the deviation correction coefficient of the current moment to obtain a corrected enthalpy loss distribution function of the current moment; Determining a flow field correction source item at the current moment according to the corrected enthalpy loss distribution function at the current moment and the heat balance correction enthalpy loss coefficient at the current moment, wherein the heat balance correction enthalpy loss coefficient at the current moment is calculated according to the field data at the current moment and the enthalpy of each node at the current moment; According to the temperature field distribution at the current moment, calculating a heat conduction item at the current moment, and according to the boundary condition at the current moment, calculating a boundary heat flow item at the current moment; Based on the flow field correction source item at the current moment, the heat conduction item at the current moment and the boundary heat flow item at the current moment, iteratively updating the enthalpy values of all nodes at the current moment to obtain the enthalpy values of all nodes at the next moment; according to the enthalpy value of each node at the next moment, table lookup interpolation is carried out through a thermophysical parameter mapping relation, and the temperature field distribution at the next moment is obtained; and (3) stepping the time to the next moment, and returning to the step of acquiring the field data at the current moment until the casting process is finished.
2. The method for calculating a molten steel temperature field based on thermal power balance and flow field characteristics according to claim 1, wherein the pre-constructed enthalpy loss distribution function is obtained by: Constructing a three-dimensional flow field coupling model of the crystallizer, and performing simulation calculation on the three-dimensional flow field coupling model of the crystallizer to obtain enthalpy loss data of a molten steel section of the crystallizer in a stable state; Normalizing the space coordinates corresponding to the enthalpy loss data to obtain node normalized coordinates; and fitting the enthalpy loss data and the corresponding node normalized coordinates to obtain an enthalpy loss distribution function.
3. The method for calculating the molten steel temperature field based on the thermal power balance and the flow field characteristics according to claim 2, wherein the calculation formula of the node normalized coordinates is: ; Wherein, the And Normalizing coordinates for the nodes; And Is a node corner mark; is the step length in the X direction; is the step length in the Y direction; The section width of the casting blank is in mm; The thickness of the section of the casting blank is in mm; the enthalpy loss distribution function has the expression: ; Wherein, the Is that And Is a distribution function of enthalpy value loss; 、、、、、、、、、、、、、、、、、 And Fitting coefficients; And Coordinates are normalized for the nodes.
4. The molten steel temperature field calculation method based on the thermal power balance and the flow field characteristics according to claim 1, wherein the calculation formula of the corrected enthalpy loss distribution function at the current moment is: ; Wherein, the For the current moment Correcting the enthalpy value loss distribution function; Is that And Is a distribution function of enthalpy value loss; And The coefficient is corrected for the degree of deviation.
5. The method for calculating a molten steel temperature field based on the characteristics of heat power balance and flow field according to claim 1, wherein the calculation formula of the heat balance correction enthalpy loss coefficient at the present moment is: ; Wherein, the For the current moment A heat balance correction enthalpy loss coefficient; For the current moment The cooling energy loss of the wide copper plate of the crystallizer; For the current moment The cooling energy loss of the narrow-side copper plate of the crystallizer; For the current moment The energy loss of the whole molten steel in the crystallizer.
6. The method for calculating the molten steel temperature field based on the thermal power balance and the flow field characteristics according to claim 1, wherein the heat conduction item at the current moment is calculated according to the temperature field distribution at the current moment, specifically: ; Wherein, the For the current moment Node Is a heat conducting item of (a); the standard quality of the grid where the node [ i, j, k ] is located at 20 ℃; to calculate a time step; Is a surrounding node; the number of surrounding nodes that are nodes [ i, j, k ]; For the current moment The area of the shared surface of the grid where the node [ i, j, k ] is located and the grid where the node around the node (r) is located; For the current moment The integrated thermal conductivity between node [ i, j, k ] and its (r) th surrounding nodes; For the current moment Corner marks of the r-th surrounding nodes of the nodes [ i, j, k ]; for node [ i, j, k ] at the current time Is a temperature field distribution of (a); For the current moment The perpendicular line distance between the connection line of the node [ i, j, k ] and the (r) th surrounding node of the node [ i, j, k ] and the common surface of the grid where the two nodes are located; According to the boundary condition of the current moment, calculating a boundary heat flow item of the current moment, specifically: ; Wherein, the For the current moment Node B [ i, j, k ] [ r ] [ t ] is the boundary heat flow term of the node [ i, j, k ] at the current moment The boundary area corresponding to the r coordinate axis of the grid; For the current moment Boundary heat flux density corresponding to the (r) th coordinate axis of the grid where the node [ i, j, k ] is located.
7. The molten steel temperature field calculation method based on the thermal power balance and the flow field characteristics according to claim 1, wherein the calculation formula of the flow field correction source term at the current moment is: ; Wherein, the For the current moment A flow field correction source term; For the current moment A heat balance correction enthalpy loss coefficient; For a modified enthalpy loss distribution function.
8. The molten steel temperature field calculation method based on the heat power balance and the flow field characteristics according to claim 1, wherein the iterative updating is performed on the enthalpy value of each node at the current moment based on the flow field correction source item at the current moment, the heat conduction item at the current moment and the boundary heat flow item at the current moment to obtain the enthalpy value of each node at the next moment, specifically: ; Wherein, the For the next time t+ [ delta ] t node Is updated by the enthalpy value; For the current moment Node Enthalpy value of (2); Is a weight proportionality coefficient; For the current moment Node Is a heat conducting item of (a); For the current moment Node Boundary heat flow terms of (2); For the current moment Node Is a flow field correction source term.
9. A computer device comprising a memory, a processor and a computer program stored on the memory and capable of running on the processor, characterized in that the processor executes the computer program to implement the method of calculating a molten steel temperature field based on thermal power balance and flow field characteristics according to any one of claims 1-8.
10. A computer-readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed by a processor, implements the molten steel temperature field calculation method based on thermal power balance and flow field characteristics as claimed in any one of claims 1 to 8.

Description

Molten steel temperature field calculation method and related device based on thermal power balance and flow field characteristics Technical Field The application relates to the technical field of control of a ferrous metallurgy continuous casting process, in particular to a molten steel temperature field calculation method based on thermal power balance and flow field characteristics and a related device. Background In the continuous casting production process, the crystallizer is used as an initial stage of solidification forming of molten steel, and the distribution characteristic of the temperature field of the molten steel in the crystallizer is one of core factors for determining uniform growth of a solidified shell of a casting blank and final casting blank quality. The accurate calculation of the temperature field of molten steel in the crystallizer has direct influence on the optimal allocation of dynamic secondary cooling water and the accurate setting of dynamic soft reduction process parameters, and is also an important foundation for guaranteeing the smooth running of the continuous casting production process and the reliable operation of a steel leakage forecasting system. At present, for analysis of a molten steel temperature field in a crystallizer, solving calculation is generally performed by constructing a differential equation of a Fourier heat conduction law based on classical theory of heat transfer. In a conventional calculation model, the central region of the mold is usually preset as the highest temperature hot zone, and the distribution simulation of the entire temperature field is performed based on this. The traditional heat transfer calculation method is widely applied to various industrial thermal process analyses. However, the actual conditions in continuous casting crystallizers are extremely complex. After molten steel is injected into a crystallizer through a submerged nozzle, a specific flow field shape is formed. In the actual production process, after molten steel flowing in from the submerged nozzle enters the crystallizer, a part of molten steel flowing out from the nozzle side holes forms a short-circuit flow, and the flow directly rushes to and approaches to the wide-surface areas on two sides of a casting blank, and then continuously flows to the lower part. This flow field driven convective heat transfer mechanism causes the high temperature molten steel to be carried more to the side regions of the mold where heat is collected. In contrast, the molten steel located in the middle of the mold experiences more cooling environment due to its longer flow path and is less directly affected by the main flow, and its temperature is rather relatively low, as shown in fig. 1. The temperature distribution characteristic dominated by the actual flow field enables the crystallizer to actually present a distribution state of 'hot at two sides and cold in the middle'. The traditional calculation method is difficult to accurately reflect the temperature redistribution phenomenon driven by the actual flow field. In the prior art, even if the model is attempted to be corrected by empirically amplifying parameters such as the heat conductivity coefficient, the calculated temperature distribution form cannot be fundamentally changed, and the objective physical process of transferring the high-temperature region to two sides cannot be effectively simulated. This results in systematic deviations between the simulation results of the temperature field and the measured data, which in turn affect the accuracy of the continuous casting process control model. Disclosure of Invention The application aims to provide a molten steel temperature field calculation method and a related device based on thermal power balance and flow field characteristics, which can obviously improve the calculation precision of the molten steel temperature field in a crystallizer and provide an accurate data basis for the subsequent dynamic secondary cooling water control and dynamic soft reduction process. In order to achieve the above object, the present application provides the following solutions: In a first aspect, the application provides a molten steel temperature field calculation method based on thermal power balance and flow field characteristics, comprising the following steps: Acquiring field data at the current moment, wherein the field data comprise a blank pulling speed, boundary conditions, a crystallizer water inlet and outlet temperature and a crystallizer copper plate cooling water flow; Determining a deviation correction coefficient of the current moment according to the blank drawing speed of the current moment and the preset casting blank section size, and correcting a pre-constructed enthalpy loss distribution function by using the deviation correction coefficient of the current moment to obtain a corrected enthalpy loss distribution function of the current moment; Determining a flow field c