PRESSURE DROP IN R-245FA CONDENSATION IN TUBES FITTED WITH COILED-WIRE INSERTS

This study examines pressure drop during condensation of R-245fa pure vapor inside two separate horizontal coaxial double-pipe test sections with coiled-wire inserts assembled in series. For each inserted tube and the plain tube, data were collected for mass fluxes in the range of 100 to 250 kg/m(2)s in increments of 50 kg/m(2)s for vapor qualities ranging from 0.1 to 0.9. It was observed that the pressure drop inside a horizontal tube is a complex function of vapor quality, mass velocity, and coil pitch, and in a low vapor quality region. The highest pressure drop ratio was 13.33 for a coil pitch of 3.0 mm at a refrigerant mass flux of 150 kg/m(2)s.