Characteristics of evaporation heat transfer and flow pattern of pure refrigerant HFC134a in a horizontal capillary tube

Abstract

In the present study, the characteristics of heat transfer and flow pattern are investigated experimentally for evaporation of pure refrigerant HFC134a in capillary tubes of 2.0 and 0.84 mm I.D. The test section consists of a heating stainless steel tube section and a glass-tube section, which is located at the right after the outlet of the heating section. The experiments were carried out in the ranges of mass velocity of 100 to approximately 600 kg/m2s and heat flux of 1.16 to approximately 46.8 kW/m2 at a constant inlet pressure of about 920 kPa. Experimental results of local heat transfer coefficient, pressure drop and flow pattern were compared with previous studies.