Heat transfer coefficient of two-phase flow boiling with low vapor quality.

The use of HCFCs refrigerants are gradually being replaced by HFCs and hydrocarbons refrigerants that has zero ODP (Ozone Depletion Potential). R-290 (propane) is a hydrocarbon refrigerant with C3H8 molecular structure. In this research, the flow boiling heat transfer occurs inside small tube with diameter of 7.6 mm and length of 1.07 m. In order to determine the value of heat transfer coefficient, the experiment were carried out for mass fluxes ranging from 200 kg/m2s to 400 kg/m2s, heat fluxes ranging from 5 kW/m2 to 20 kW/m2, and saturation temperatures from 5°C to 15°C. This study analyzed the heat transfer through the local heat transfer coefficient along the flow for low vapor quality region. The boiling heat transfer coefficient of R-290 is influenced by heat flux, mass flux, and saturation temperature. In comparison to previous boiling heat transfer correlations, the correlation of Shah (1982) best fitted the experimental result with the mean deviation of 32.20%. A new correlation for boiling heat transfer coefficient was developed by modification of F factor with regression method. The new correlation has smaller mean deviation of 22.46% in comparison with the present experimental result.