CALCULATION AND EXPERIMENTAL VERIFICATION OF HEAT TRANSFER COEFFICIENT FOR LOW PRESSURE METHANOL EVAPORATOR

摘要

Natural refrigerants are attracting attention due to their environmental neutrality. They have good thermalproperties, but their evaporation pressures at near room temperatures are just a few kPa. There is limitedinformation regarding evaporation of methanol at low-pressures. Empirical correlations for boiling heattransfer coefficient that were developed at atmospheric pressure levels tend to give high errors. In this paperwe show an experimental data for pool boiling of methanol in pressure region 0.3–18 kPa and heat fluxes10–45 kW/m~2. The results are compared to calculations based on eight empirical heat transfer coefficientcorrelations. Since all of them yielded noticable errors, we suggested new constants for the power lawequation that allow more accurate prediction of heat transfer coefficient.