中文摘要：

为分析两相流传热特性和实现流型可视化研究，以替代工质R134a凝结换热两相流动为对象，设计了一个由循环动力、冷热源、对比实验段、储液蓄能装置和数据采集系统等部分组成的环路。重点制作了卧式螺旋管和水平直管对比实验段、可视化电熔石英玻璃储液罐及流型观察实验段。调试运行结果表明，保温热损失小于5％，密封试压在2．0MPa条件下漏率小于6kPa／24h，电熔石英强度高、透明度好，适于流型观察；在压力0．20—1．30MPa，质量流速61～550kg／（m2·s），干度0．02-0．52条件下拍摄到泡状流、弹状流、分层流、波状分层流和环状流等5种典型流型，并观察到一种介于波状分层流和环状流之间的波环状流的新流型。在调试运行范围内实验系统工作稳定可靠，满足中低压条件下两相传热特性和流型研究的要求。

英文摘要：

A visual two-phase flow experiment platform using alternative refrigerant R134a as working fluid was built according to principle of condensation heat transfer to study the characteristics of two-phase flow and visualization of flow pattern, which was primarily made up of circle power, cooling/heating sources, contrastive test sections, accumulator and data acquisition system. A parallel test section was designed for investigation on characteristics of two-phase flow in both horizontal helically-coiled tube and horizontal straight tube, and a reservoir and two visual sections made of electric melting-quartz glass were designed to observe flow patterns. Test results show that heat losing of the system is no more than 5%, leak ratio is no more than 6 kPa/24 h at 2.0 MPa and electric melting-quartz glass is hard enough and utilizable for visual study. Under the conditions of pressures of 0.20-1.30 MPa, mass fluxes of 61-550 kg/（m2·s）, outlet qualities of 0.02-0,52, five kinds of typical flow patterns, bubble flow, slug flow, stratified flow, wave-stratified flow and annular flow, has been observed. Especially, a new flow pattern named wave-annular flow in this paper is found, which is intervenient of wave-stratified flow and annular flow.