Effect of Flow Directions on Multiphase Flow Boiling Heat Transfer Enhanced by Suspending Particles in a Circulating Evaporation System

作     者：Feng Jiang Teng Jiang Guopeng Qi Xiulun Li 

作者机构：School of Chemical Engineering and TechnologyTianjin University School of Biological and Environmental EngineeringTianjin Vocational Institute 

出 版 物：《Transactions of Tianjin University》 (天津大学学报（英文版）)

年 卷 期：2019年第25卷第3期

页      面：201-213页

核心收录：

学科分类：12[管理学] 1201[管理学-管理科学与工程(可授管理学、工学学位)] 08[工学] 

基　　金：supported by Tianjin Municipal Science and Technology Commission  China (No. 2009ZCKFGX01900) 

主　　题：Heat transfer enhancement Circulating fluidized bed evaporator Flow direction Down-flow bed Up-flow bed Horizontal bed 

摘      要：A circulating fluidized bed evaporator(including down-flow, horizontal, and up-flow beds) was constructed to study the effect of flow directions on multiphase flow boiling heat transfer. A range of experimental investigations were carried out by varying amount of added particles(0-2%), circulation flow rate(2.15-5.16 m^3/h) and heat flux(8-16 kW/m^2). The comparison of heat transfer performance in different vertical heights of the horizontal bed was also discussed. Results reveal that the glass bead particle can enhance heat transfer compared with vapor-liquid two-phase flow for all beds. At a low heat flux(q = 8 kW/m), the heat-transfer-enhancing factor of the horizontal bed is obviously greater than those of the up-flow and down-flow beds. With the increase in the amount of added particles, the heat-transfer-enhancing factors of the up-flow and down-flow beds increase, whereas that of the horizontal bed initially increases and then decreases. However, at a high heat flux(q=16 kW/m), the heat-transfer-enhancing factors of the three beds show an increasing tendency with the increase in the amount of added particles and become closer than those at a low heat flux. For all beds, the heat-transfer-enhancing factor generally increases with the circulation flow rate but decreases with the increase in heat flux.