制备非晶薄带冷却辊流动换热特性及协同优化

为改善平面流铸冷却辊的换热特性,提高Fe-Si-B非晶薄带的横向厚度均匀性,建立了冷却辊轴向换热通道数值计算模型。在分析现有通道流动换热特性基础上,提出一种球面形换热通道设计方法。基于场协同理论,综合换热与流阻,对所提球面形通道进行优化,并进行实验验证。结果表明:通道内冷却水换热效率沿水流方向逐渐下降,与冷却辊换热主要发生在靠近冷却辊内壁位置,现有冷却辊宽度中部温度远大于两端,轴向温差明显;球面形通道可以加强冷却辊中部换热,降低外壁温度、热变形和轴向变形差,进而改善非晶薄带横向厚度均匀性;随着球面半径的减小,通道中部换热明显增强,但流阻随之急剧增大;综合流阻与换热特性,存在最优通道优化半径。

Flow and Heat Transfer Characteristics and Collaborative Optimization of Cooling roller for Preparing Amorphous Ribbons

In order to improve the heat transfer characteristics of plane flow casting cooling roll and improve the transverse thickness uniformity of Fe-Si-Be amorphous strip, a numerical model of axial heat transfer channel is established. Based on the analysis of the current axial flow and heat transfer characteristics of cooling roller, a design method of spherical heat transfer channel is proposed. Based on the field synergy theory, the spherical channel is optimized and verified by experiments. The results show that the heat transfer efficiency of the cooling water in the channel decreases gradually along the water flow direction, and the heat transfer mainly occurs near the inner wall of the cooling roller. The temperature in the middle of the existing cooling roller outer wall is much higher than that at both ends, and the axial temperature difference is obvious. The spherical channel can strengthen the heat transfer in the middle of the cooling roller, reduce the temperature, thermal deformation and axial deformation difference of the outer wall, and significantly improve the transverse thickness of the amorphous thin strip with the decrease of the radius of the sphere. The heat transfer in the middle of the channel increases obviously, but the flow resistance also increases sharply. There is an optimal channel optimization radius based on the comprehensive flow resistance and heat transfer characteristics conditions.