Research of the Heat Transfer Characteristic for Compound Hollow Heat Pipe

In order to solve the engineering problems of a large number of low-quality flue gas waste heat recovery and acid dew point corrosion leading to failure of the device easily, a new kind of heat transfer component named a compound hollow heat pipe was proposed. Its structure and working principle was introduced. Its internal heat transfer mechanism is analyzed, and its start-up characteristics, isothermal temperature performance and heat transfer properties were studied. The results show that compound hollow heat pipe can start and work fast while the outer tube wall temperature is 30 °C within 2 min heating time. And in the natural air convection cooling conditions, it has good isothermal characteristics. The heat transfer coefficient of the compound hollow heat pipe increases with the cooling water Reynolds number. When the heating steam temperature is below 125 °C and the cooling water Reynolds number is 6650, the heat transfer coefficient of the compound hollow heat pipe is 1350 W.m^-2.°C^-1. Experimental results of the compound hollow heat pipe provide the basis of engineering applications for heat exchanger.