相变乳状液在蛇形管中的流动和传热特性

FLOW AND HEAT TRANSFER CHARACTERISTICS OF PHASE-CHANGE EMULSION IN A COILED DOUBLE-TUBE HEAT EXCHANGER

用正十四烷、复合表面活化剂和水制成O/W型相变乳状液作为相变蓄冷及传热介质,对其作为非牛顿流体和固液两相流的流动和传热特点进行了分析,通过测试得出不同浓度乳状液在蛇形管道中的对流换热Nυ数和摩擦系数,并给出了换热和阻力的无量纲关联式。指出了对这类特殊相变蓄冷材料作进一步研究的方向。

An O/W-type phase-change emulsion synthesized by tetradecane, water and combined surfactants was used as a latent heat storage and heat transfer medium, analyses were made for the flow and heat transfer characteristics of the emulsion, which is not only a non-Newtonian fluid, but also a solid-fluid two phase flow. The convective heat transfer Nu number and friction factor of the emulsion with different concentrations in the coiled double-tube heat exchanger were obtained by experimental tests, and relative non-dimensional correlations of heat transfer and flow resisitance were derived. Furthermore, research developments for this type of phase-change emulsion was reviewed.