Flow boiling of R32 in a horizontal smooth tube of 6.0 mm internal diameter: heat transfer coefficient and pressure drop

This paper presents a series of experiments on flow boiling heat transfer coefficient and pressure drop using refrigerant R32. Tests were performed in a smooth horizontal stainless steel tube with an internal diameter of 6.00 mm, with the heat directly applied on the test section tube through DC current. Trends of the heat transfer coefficient and pressure drop data are displayed for different operating conditions. Specifically, the saturation temperature was fixed to 25 and 35 degrees C, the heat flux varied from 5 to 50 kW/m(2) and the mass velocity was fixed to the low values of 150 and 250 kg/m(2) s. The effects of the operating parameters on the heat transfer results are also shown.