Experimental Investigation on Evaporation Heat Transfer and Pressure Drop Characteristics of HFC-161 in a Horizontal Smooth Tube

The evaporation heat transfer and pressure drop characteristics of HFC-161 in a horizontal smooth tube with an inside diameter of 9 mm was experimentally investigated. The local heat transfer coefficient and total pressure drop were measured at the heat flux ranging from 15 – 25 kW/m, the mass flux ranging from 100 – 200 kg/(m·s), and the evaporation temperature of 5, 10 °C. The experimental results showed that the evaporation heat transfer coefficient increased with the vapor quality except in the high vapor quality region, increased with the mass flux and the heat flux, and decreased with the saturation temperature across the experimental conditions. By comparison, the measured heat transfer coefficient of HFC-161 is higher than that of R22. In addition, the measured total pressure drop of two-phase HFC-161 in the test tube increased strongly with the mass flux within the experimental range. The presented results are helpful in designing more compact and effective heat transfer exchangers for the airconditioning systems using HFC-161.