喷雾冷却中液滴冲击壁面的流动和换热

FLOW AND HEAT TRANSFER OF DROPLET IMPINGING ON HOT FLAT SURFACE DURING SPRAY COOLING

喷雾冷却中液滴冲击壁面的流动和换热强弱可用铺展系数和冷却效能的大小来反映。本文利用Volume-of- Fluid(VOF)方法,对初始直径在50～150μm,初始速度在1.0～10.0 m/s之间的单个液滴冲击恒温发热表面的情况进行了数值模拟。模拟结果表明,增加液滴的初始速度和直径会扩大液滴的铺展范围,即铺展系数增大;液滴的初始直径越小、速度越大,则其冷却效能越大,即冷却能力越强。定量结果对喷雾系统的设计具有重要意义。

Flow and heat transfer of spray cooling can be reflected by a droplet spreading coefficient, which is dependent on the droplet initial size and velocity.By the method of Volume-of-Fluid (VOF), a droplet impinging on a constant temperature flat surface is investigated numerically,the droplet size is between 50～150μm,and the velocity is between 1.0～10.0 m/s.The numerical results show that, the maximum spreading coefficient will increase with its initial size and impact velocity.When the initial size is smaller and the impact velocity is bigger,the cooling effectiveness will be higher.The quantitative results are important for the design of spray cooling system.