Experimental Study of Flow Patterns and Improved Configurations for Pulsating Heat Pipes

作     者：Shi LIU Jingtao LI Xiangyuan DONG Huanzhuo CHEN 

作者机构：Institute of Engineering Thermophysics Chinese Academy of Sciences EO. Box 2706 Beijing 100080 China 

出 版 物：《Journal of Thermal Science》 (热科学学报（英文版）)

年 卷 期：2007年第16卷第1期

页      面：56-62页

核心收录：

学科分类：080702[工学-热能工程] 08[工学] 0807[工学-动力工程及工程热物理] 

基　　金：the National Natural Science Foundation of China under contract 60672151   60532020 

主　　题：pulsating heat pipe flow patterns improved configurations. 

摘      要：A series of experiments were performed on three types of closed loop pulsating heat pipes （PHPs）, intending to investigate various kinds of flow patterns, and to develop some improved configurations for the PHPs. Optical visualization results indicated that there might exist three flow patterns, i.e. bubble-liquid slug flow, semi-annular flow and annular flow, corresponding to different working conditions. For a given geometry and an adequate fill ratio, the PHPs had the self-adjusting characteristic for the flow patterns （from slug flow to semi-annular and then to annular flow） to meet the demands of the increasing heat input. Two special configurations, one with alternately varying channel diameter, the other equipped with one section of thicker tube, were found to be advantageous in establishing and maintaining reliable circulation of the working fluid. The thermal performance of the PHPs was examined over a range of working conditions. Comparing with the normal PHP with uniform diameter, either of the improved PHPs exhibited higher thermal performance.