差异演化算法在热连轧工作辊温度仿真中的应用

针对热连轧工作辊温度仿真计算,给出了忽略热载荷在时域内初始相位差的轴对称模型。通过对模型特点的分析,指出忽略热载荷在时域内初始相位差的轴对称模型实际是一种三维仿真模型,并根据此仿真模型建立了变步长计算温度场的有限差分方程。由氧化铁皮厚度的线性函数来近似表示工作辊与轧件等效换热系数,由喷射区水冷换热系数和喷射区之间的水冷系数计算得到工作辊与冷却液等效换热系数。针对差异演化算法后期收敛速度下降,甚至有时会陷入局部最优点的缺陷,提出根据种群聚集度来动态调整缩放因子,同时引入求解域内的均匀变异操作。并用改进后的差异演化算法对两种等效换热系数进行了优化。仿真结果与实测结果规律一致,证明忽略热载荷在时域内初始相位差的轴对称模型经差异演化算法优化参数后能准确预报工作辊的温度场。

Research on Work Roll Temperature with Improved Differential Evolution in Hot Strip Rolling Process

In accordance with the dynamic forming process of work roll temperature field,a kind of axisymmetrical model,neglecting initial phase difference of thermal load model was proposed.Through the analysis of the axisymmetrical model,it was pointed out that the neglecting initial phase difference of thermal load model was a 3 dimension-model in essence.The finite difference equations with various steps were developed based on this simulation model.The roll bite effective heat transfer coefficient was approximated as a linear function of the scale thickness.The cooling effective heat transfer coefficient was expressed as a function of heat transfer coefficient associated with spray cooling and inter-spray cooling.Aiming at convergence speed of different evolutionary fall in final stage,sometimes the result trap to local optimum,the scaling factor was changed dynamically based on the aggregation degree of the population,and the uniformity mutation operation was added.The two kinds of effective heat transfer coefficients were optimized by different evolutionary.The simulation result is identical with the data measured from hot strip rolling,which is proved the validity of the simulation method.