结合高速摄像和电容层析成像技术,对脉动热管进行了可视化测量研究.从流型和流向两方面分析了脉动热管的运行机理和传热特性.根据受力分析对脉动热管的结构进行了改进.结果表明:脉动热管存在3种不同流型,即塞状流、环状流以及两者共存的混合流,其对应的影响因素、运行特性与传热强度也不同;从流动方向来看,脉动热管内工质的流动可分为脉动流和循环流;对脉动热管的改进说明改变脉动热管流道的对称性和均衡性有利于循环流的形成和维持.
Visualization measurement and study on pulsating heat pipe (PHP) was carried out by use of the high-speed photography and electrical capacitance tomography (ECT). The operation mechanism and heat transfer characteristics of the PHP were analyzed from the view of flow pattern and flow direction. According to the analysis of the forces, the structure of the PHP was improved. Results show that there are three flow patterns, i. e. slug flow, annular flow and mixed flow of slug and annular flow, corresponding to different affecting factors, operating characteristics and heat transfer intensity. In terms of flow directions, flow in the PHP can be classified as local oscillatory flow and bulk circulatory flow. The improvement on the PHP indicates that it is favourable to the formation and sustaining of the circulatory flow to change the symmetry and uniformity of the flow channel of the PHP.