汽-液-液三相垂直管内充分发展流传热性能

研究了垂直管内连续相水和分散相戊烷泡滴之间的流动和传热性能 .在全面考虑了汽体的膨胀、水蒸气的蒸发、界面张力的作用、汽液两相的相互作用和滑移、泡滴的破碎等影响因素的基础上 ,建立了与实验结果吻合较好的一维流体力学模型和传热模型

DIRECT CONTACT HEAT TRANSFER BETWEEN TWO IMMISCIBLE LIQUIDS IN VERTICAL TUBE

In this paper, the performance of fluid dynamics and heat transfer between continuous and dispersed phases is studied for pentane-water system in a gas-liquid-liquid three-phase vertical tube. The gas-liquid-liquid three-phase section is divided into two stages. In the first stage the droplets number density is assumed to be unvarying but the diameter increases gradually, while in the second stage the diameter of droplet is kept constant value but the droplet number density is a variable. Under this assumption some models such as one-dimensional two-fluid dynamics model, local volumetric heat transfer coefficient, average volumetric heat transfer coefficient and single droplet heat transfer coefficient are developed. These models take into account the variation of gas density due to expansion in the tube, the evaporation of continuous-phase water, the action of interfacial tension, the velocity slip and interaction between gas and liquid, and two-phase bubbles break-up. The main characteristic parameters of fluid flow are also analyzed in detail. The calculated results showed good agreement with the experimental values.