含空气逸流的水平管外冷凝实验装置设计

摘要

设计了利用文丘里抽吸形成空气逸流来改善水平管外冷凝换热的实验装置.基于能量守恒、对数平均温差法和喷管原理,给出了合理的蒸发器、冷凝段和空气逸流装置结构.随着蒸发器加热功率的增加,蒸发器长度、蒸汽质量流量和冷凝段长度将增加;随着蒸汽压力增加,蒸发器和冷凝段长度均下降,空气逸流量将增加.在套管周向开设空气逸流口,采用空气逸流管使之与文丘里管喉段相接,利用文丘里抽吸排除冷凝空间中的空气.%An experimental device was designed for the air drainage which generated by Venturi suction to improve condensation heat transfer over horizontal tube.Basing on the energy conservation, LMTD method and nozzle principle, the reasonable structures of the evaporator, the condensation section and the air drainage device were given out.With the increase of the evaporator''s heating power, the evaporator''s length, the vapor mass flux and the condensation section length increase;As vapor pressure increases, the lengths of both the evaporator and condensation section decrease but the air drainage mass flux goes up.Several air drainage holes were set along circumferential direction of the horizontal tube;and making use of air drainage tubes to connect it to the throat section of Venturi tube to discharge air in condensation section by means of Venturi suction.