磨削工件表面含湿空气射流冲击的换热

Heat Transfer on Grinding Workpiece Surface Subjected to Mist/Air Impinging Jet

针对磨削工件表面的射流冲击对流换热过程,一方面,通过数值研究,揭示旋转表面诱导的气旋和射流冲击的耦合流动换热特征;另一方面,通过实验研究,定量分析含湿空气射流冲击的强化换热效果。研究结果表明,当盘缘在射流冲击喷嘴附近的切向速度与射流冲击方向协调时,旋转盘诱导的气旋运动和射流冲击的耦合作用有利于改善磨削弧区的对流换热,随着转盘旋转速度的增加,其强化对流换热的效果更显著;采用含湿空气作为冲击射流可以显著提高加热壁面的冷却效果。

Investigation is carried out to illustrate some of the flow and heat transfer characteristics that occur when a single-air jet or mist/air jet impinges on a flat plate with a rotating disk mounted above the surface, the representative of the workpiece in a grinding process. The first objective aims to assess the detailed flow and heat transfer features in the vicinity of a rotating grinding wheel with jet impingement directed at grinding zone by numerical investigation. The second objective aims to assess the quantitative evaluation for heat transfer enhancement on a grinding workpiece surface subjected to the mist/air jet impingement by experimental investigation. The results show that the coupled action of swirl air entrainment and jet impingement is benefit for convective heat transfer enhancement near grinding region when the jet impinging direction is consistent with the rotating direction of rotating disk, especially at higher rotating speed. Furthermore, the increasing of water droplet in mist cooling can enhance the cooling effect significantly.