喷雾冷却系统中雾化特性影响因素研究

Research on influence factors of atomization characteristics in spray cooling system

为研究喷雾式蒸发冷却超级计算机中喷射压力和喷嘴口径对喷雾雾化质量的影响,采用相位多普勒粒子分析仪(PDPA)对成雾状况做了精确测量,分析了雾化参数——雾滴速度、雾滴粒径与喷雾压力、喷嘴口径之间的关系。研究发现:喷雾的粒径分布呈现中间小、两边大的趋势,喷雾速度呈现中间大,两边小的趋势。随着喷雾压力的增加,喷雾的Sauter平均直径(SMD)逐渐变小,雾滴粒径分布趋向均匀,同时喷雾的平均速度变大。随着喷嘴口径的减小,雾滴粒径逐渐变大,速度则先增大后减小。平均SMD与喷雾压力P之间呈指数减小,平均速度V与喷雾压力P之间呈线性关系。平均SMD与喷嘴口径和压力有很好的二元线性关系。

In order to do research on the effect of injection pressure and orifice diameter on spray atomization quality in spray evaporative cooling super computer,the Phase Doppler Particle Analyzer（ PDPA） was used to take a precise measurement of spraying conditions and then analysis the relationship between atomization parameters such as droplet velocity,droplet diameter and injection pressure and the structure of nozzle. Droplet size distribution shows that the Sauter mean diameter（ SMD） in the central axis is smaller than that of the outer sides. With the increase of injection pressure,SMD decreases remarkably and the number of big droplets is decreased. Meantime,the mean velocity of droplets increases gradually. With the decrease of orifice diameter,the mean SMD increases but the mean velocity increases firstly and then decreases. The mean SMD decreases exponentially with the increase of injection pressure. The mean velocity is linear with injection pressure. There is a good binary linear relationship among mean SMD,orifice diameter and injection pressure.