强化管管外升膜蒸发换热特性实验

升膜蒸发是利用微细槽道对液体的毛细抽吸作用,在强化管外表面覆盖一层薄液膜,进而以薄膜蒸发的形式实现强化换热.本文针对强化管在水中的浸入深度,蒸发压力,加热壁面过热度等因素对升膜蒸发换热性能的影响展开实验研究.实验结果表明随着管外液位的降低升膜蒸发换热系数明显提高,此外,蒸发压力和加热壁面过热度因素对升膜蒸发换热性能也有着显著的影响.

EXPERIMENTAL RESEARCH ON RISING FILM EVAPORATION ON THE OUTER SURFACE OF AN ENHANCED TUBE

Liquid can be lifted to some height by capillary force.Thus,for a horizontal enhanced tube with fine outer grooves,a thin liquid film will be formed on its' outer surface when just the partial of the tube is immerged into liquid.So,a high efficient evaporation can be obtained resulting from the thin liquid film.Experimental results have indicated that evaporation heat transfer coefficient and heat flux can be increased markedly with the decrease of the immersion depth of the tube in water. Besides,phase-change pressure and heat transfer temperature difference have also obvious effect on heat transfer performance.