Conference Year



dimpled flat duct, flow boiling, heat transfer, pressure drop


Among various heat transfer enhancement technologies, the dimpled surface, which is inspired by the resistance reduction characteristics of the specific concaves on golf balls, has the potential to improve heat transfer with a relatively low pressure-drop penalty. More and more applications of dimpled surfaces in heat exchangers have shown up in industries. However, the lack of experimental data, especially the heat transfer and pressure drop data for liquidand-vapor two-phase flow, inside the dimpled flow channels prevents the good design of the dimpled heat exchangers. In this study, a facility has been designed and built to investigate the heat transfer and pressure drop of flow-boiling R1234yf in a dimpled flat duct. The details of the facility, especially the test section, are presented. A microscope is used to measure the geometrical dimensions of the dimpled flat tube. The heat loss is tested and the heat balance is -2 -1 checked before the experiments. The experiments are performed at mass flux from 100 to 200 kg m s , heat flux of 5 kW m-2, saturation temperature of 15 oC, and vapor quality from 0.1 to 0.95. The experimental results are presented and discussed in detail.