Abstract: In order to solve the engineering problems of a large number of low-quality flue gas waste heat recovery and device failure caused by acid dew point corrosion，a new heat transfer component named compound hollow heat pipe was proposed. Its structure and working principle were introduced. A visual experimental device was established to analyze the mechanism of heat and mass transfer between the vapor-liquid two-phase flow inside the compound hollow heat pipe，at the same time，the experiments on wall isothermal characteristic with different filling rate were carried out. The results show that： nucleate boiling heat transfer exists inside the compound hollow heat pipe，and laminar film condensation of saturated steam is found on the inner side of outer wall when the inner tube is heated by alcohol stove and outer tube was cooled by air convection. When the wall is heated about 2 minutes and temperature increases to about 30 ℃，compound hollow heat pipe can start and work fast. When filling rate is 33%，isothermal characteristic of the wall shows its best performance. Experimental results of the compound hollow heat pipe provide the basis of engineering applications for heat exchanger.

Key words: compound hollow heat pipe, filling rate, visualization experiment, isothermal characteristic, saving energy

摘要： 为了解决工业中大量低品质烟气余热的回收利用和烟气酸露点腐蚀导致设备容易失效的工程问题，提出了一种复合中空热管传热元件，介绍了其结构及工作原理。采用可视化实验对管内气液两相流的传热传质机理进行了分析，同时，对不同充液比情况下管壁的等温性进行了实验研究。研究结果表明：在内管采用酒精炉加热、外管采用空气自然对流冷却的条件下，复合中空热管管内液池为核态沸腾换热，外管壁内侧是饱和蒸气层流膜状凝结；复合中空热管在外管壁温度30 ℃时，加热时间2 min之内就能正常快速启动工作；充液比33%时，复合中空热管的等温性好。实验研究结果为复合中空热管换热器的工程应用提供了基础。

关键词: 复合中空热管, 充液比, 可视化实验, 等温性, 节能