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

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 0.84mm I.D. The test section consists of a h eating stainless steel tube section and a glass-tube section, which is loca ted at the right after the outlet of the heating section. The experiments w ere carried out in the ranges of mass velocity of 100 similar to 600 kg/m(2 )s and heat flux of 1.16 similar to 46.8 kW/m(2) at a constant inlet pressu re of about 920 kPa. Experimental results of local heat transfer coefficien t, pressure drop and flow pattern were compared with previous studies.