EXPERIMENTAL STUDY OF HEAT TRANSFER, PRESSURE DROP, AND DRYOUT FOR FLOW BOILING OF WATER IN AN OIL HEATED MINICHANNEL

摘要

Heat transfer and pressure drop, are experimentally recorded for flow boiling water in a single 706 μm circular copper channel 158.75 mm long. Heat is supplied by heat transfer oil at specified temperatures to a helical channel in the test section. In contrast to other current experimental techniques for flow boiling in small diameter tubes, a uniform temperature boundary condition is employed rather than a constant heat flux condition. The principal results of these experiments are two-phase flow boiling heat transfer rates and an analysis of the time-dependent pressure drop signature during two-phase flow in a minichannel. The range of experiments includes mass fluxes of 43.8-3070 kg/m~2 s and wall temperatures of 100℃-171.2℃. In all cases the test section water inlet is subcooled to between 72.9℃ and 99.6℃. The inlet pressures used are 1.1-230.5 kPa (gage).