水蒸气在竖直微细管外凝结传热特性研究

Research of Condensation Heat Transfer of Water Vapor on External Wall of Vertical Micro Tube

针对不同压力和不同流速下的饱和水蒸气在竖直微细圆管(内外径分别为0.571 mm和0.793 mm)外的凝结传热特性分别进行了实验研究,分析了蒸气压力和蒸气流速对凝结传热特性的影响。实验结果表明,凝结传热表面传热系数随着蒸气流速的增加而增加,在较高的蒸气压力下增加的更明显,且大于相同实验条件下的Nusselt理论分析解。在蒸气流速为2 m·s^(-1)时,凝结传热系数随压力的变化不大;在4 m·s^(-1)和6 m·s^(-1)时,随着蒸气压力的升高,凝结表面传热系数明显增大。

This article experimental studied effect of vapor pressure and vapor velocity on the condensation heat transfer characteristics of Saturated vapor on external wall of vertical micro tube（inner and outer diameter were 0.571/0.793 mm） were investigated, and analyzed the effect of vapor pressure and velocity on condensation heat transfer. The experimental result indicated that the condensation heat transfer coefficients increased with increasing vapor velocity, and the heat transfer coefficients increased significantly when the high vapor pressure was high. The result was greater than Nusselt theoretical analysis solution. Condensation heat transfer coefficient almost constant with increasing vapor pressure at the vapor velocity of 2 m.s^-1. However, the condensation heat transfer coefficients increased obviously with increasing vapor pressure when the vapor velocity were 4 m.s^-1 and 6 m.s^-1.