高效传热管的实验研究

建立了样机型模块式溴化锂吸收式制冷机高效传热管试验台；对研制成功的高效传热管在接近工业条件下进行了传热传质性能和添加表面活性剂影响的实验研究，提供了可供工程设计使用的关联式，并观察了马拉哥尼对流.实验研究表明，只有将有关技术参数如喷淋密度、冷却水和冷媒水流速等设计在合适的范围内，高效传热管才能取得较好的强化效果；吸收器高效管必须添加适量的表面活性剂，才能获得最佳传热传质效果.使用本文的高效传热管可使一台1160 kW的溴化锂吸收式制冷机节省铜材1700～2000 kg，质量减轻30%～40%.

ENHANCED HEAT TRANSFER TUBES

A modular prototype apparatus was designed and built up to investigate the efficiency of the enhanced heat transfer tubes in the lithium bromide absorption refrigerator Experimental studies approximate to industrial condition were carried out to investigate the heat and mass transfer performance of the three types of developed enhanced tubes and the effect of adding surfactant.Furthermore, the empirical equations given in this paper can be used for engineering design.Marangoni convection was observed in the experiments.The results of the experimental studies reveal that in order to achieve higher effectiveness of the enhanced tubes, the technical parameters involved, such as spray density and velocity in tube side, have to be adjusted accordingly.It is necessary to add surfactant properly for the best heat and mass transfer enhancement when constant curvature surface is used in the absorber.With the enhanced tubes in this paper, the copper needed in 1160 kW lithium bromide absorption refrigerator may be reduced by 1700 kg to 2000 kg and the mass of the machinery may be reduced by 30% to 40 %.