热金属表面多喷嘴风冷过程气-固耦合传热模拟

目的 获得多喷嘴风冷过程的界面换热系数,并研究风冷工艺参数对界面换热的影响规律.方法 基于Fluent软件对三喷嘴强制风冷传热过程进行"气-固"耦合分析,获得高压气流的流速场和钢板表面温度场.基于"气-固"耦合分析得到钢板表面平均温度曲线,利用自开发的反传热软件计算得到"气-固"耦合界面换热系数,并将界面换热系数以第三类边界条件施加在钢板表面进行瞬态传热分析.结果 对于直径为4 mm的喷嘴,当喷嘴间距为10～16 mm时,喷嘴间距对高压气体的流速场影响较大,气流的卷吸效应随着喷嘴距离的增大而增强;喷嘴间距对界面换热系数影响较小,喷嘴至钢板表面的距离对界面换热系数影响较大;随着喷嘴至钢板表面距离的增大,各股气流逐渐汇合为一股,各股气流的滞止区也逐渐汇合,钢板表面温度更加均匀;将界面换热系数以第三类边界条件施加在钢板表面进行瞬态传热分析,得到的钢板表面温度与"气-固"耦合分析得到的钢板表面平均温度曲线吻合得较好.结论 获得的界面换热系数可为多喷嘴风冷过程数值模拟提供可靠的数据,保证温度场的求解精度.

Gas-Solid Coupling Heat Transfer Simulation of Multi-Nozzle Air-Cooling Process on Hot Metal Surface

In order to calculate the interfacial heat transfer coefficient (IHTC) of multi-nozzle air cooling process and study the influence of air cooling process parameters on the interfacial heat transfer. With Fluent software, air cooling process with three nozzles was simulated to analyze the gas-solid coupling process, and the velocity field of high pressure airflow and the surface temperature field of steel plate were obtained. Based on the gas-solid coupled average surface temperature curve, the IHTC was calculated by the self-developed inverse heat transfer software, and the transient thermal analysis was carried out by applying the IHTC as the third boundary condition to the cooling surface. When the nozzle space varied from 10 mm to 16 mm (nozzle with a diameter of 4 mm), the nozzle space has a great effect on the velocity field of high pressure flow, and the entrapment effect of flow increases with the increase of the nozzle space. The distance between the nozzle and the steel plate has a greater influence on the IHTC than the nozzle space. With the increase of the distance between the nozzle and the surface of the steel plate, each stream of flow converges into one stream gradually, and the stagnation zone of each stream of flow also converges, then the surface temperature of the steel plate becomes more uniform. The IHTC is applied to the surface of the steel plate with the third type of boundary conditions for transient thermal analysis. The surface temperature of the steel plate obtained is in good agreement with the average temperature curve of the steel plate surface obtained by the gas-solid coupling analysis.The calculated IHTC can provide reliable data for the numerical simulation of multi-nozzle air-cooling process and improve the accuracy of temperature field.