The Influence of Wall Temperature on Total Pressure Drop During Condensation of R134a Inside a Dimpled Tube

The present study discusses the influence of wall temperature during condensation of R134a in a dimpled tube. The inside diameter and length of the dimpled section were considered as 8.38 and 500 mm. The dimpled tube specifications were considered as 5.08 mm axial pitch, 1 mm dimple diameter, and 4.99 mm dimple pitch. The numerical simulations were performed at a mass velocity of 25–125 kg/m2s, saturation temperature of 313 K, and wall temperatures of 308 K and 310 K, respectively. The mathematical equations were solved by using ANSYS FLUENT, and the flow field was considered transient. The variation of total pressure drops, volume fractions, and mixture velocities was discussed at different mass velocities and wall temperatures. By increasing the wall temperature, the total pressure drops were reduced and void fractions were increased with the wall temperature. Also, the comparison of wall shear stress and total pressure drops between smooth and dimpled tubes was studied.