氨喷雾相变冷却换热面温度分布特性

Temperature Distribution of Heat Transfer Surface in Spray Cooling with Ammonia

以液氨为冷却工质,针对大功率激光器350W/cm2以上散热需求进行喷雾冷却换热实验,研究了不同流量下冷却表面散热特性以及温度分布规律。实验结果表明:在加热功率和喷淋高度不变时,进口流量较大,冷却表面处于无沸腾换热,主要以强迫对流换热为主,换热表面温度低且分布均匀;流量为0.461L/min时,热流密度可达388W/cm2,热沉表面温度仅有2.6℃,温度偏差为±1.1℃;随着进口流量减小,热流密度增加,换热形式由强迫对流换热逐渐过渡到沸腾换热,从而导致热沉表面温度分布均匀性降低。

Using ammonia as coolant, experiments are performed to investigate heat transfer characteristics and surface temperature distribution for the spray cooling of 350 W/cm^2 high power solid state laser. When the heating power and spray height were constant, the cooling surface was mainly dominated by forced convective heat transfer, high inlet flow rate of liquid ammonia resulted in low surface temperature and uniform temperature distribution. When the volumetric flow was 0. 461 L/min, the cooling surface temperature was only 2.6 ℃ and the temperature deviation was ± 1. 1 ℃, the heat flux dissipated could reach 388 W/cm^2. As the inlet volumetric flow decreased, the dominant heat transfer mechanism for spray cooling gradually converted the forced convective heat transfer to the boiling while increasing heat flux, resulting in decrease of uniform temperature distribution of heat transfer surface.