紧凑满液型叉排管束蒸发换热器内水的沸腾强化换热特性

采用紧凑满液型蒸发换热器,利用水平传热管叉排管束狭窄空间内早期沸腾强化换热机理将中小热负 荷条件下的自然对流换热转化为旺盛核沸腾换热,换热性能大大优于传统的降膜式蒸发换热器。对水平传热管 管束在受限空间内沸腾强化换热进行实验研究,确认了紧凑满液式水平管蒸发换热器具有良好的换热性能,传 热管在管束中的位置对换热特性已经没有明显影响,随着压力增加,受限空间内沸腾强化换热强化效果显著增 加。

BOILING HEAT TRANSFER ENHENCEMENT IN COMPACT STAGGERED BUNDLE TYPE EVAPORATOR

The effects of tube spacing, positions of tubes and the test pressures on boiling heat transfer of water in the restricted spaces of the compact staggered bundles consisted of smooth horizontal tubes were investigated experimentally. The experimental results showed that the tube spacing has very significant effect on the boiling heat transfer in a compact tube bundle. There is an optimum tube spacing, which provides the most heat transfer coefficient at the same heat fluxes. The heat transfer coefficients for the compact tube bundle having 0.5 mm tube-spacing could increase two to three times those of pool boiling. The tube position in the bundle has not meaningful effect on the boiling heat transfer. The test pressure has significant influence on the boiling heat transfer in the compact bundle and the boiling heat transfer increases quickly with increasing the test pressure.