To investigate the effects of micro-fin geometry and operating conditions on flow evaporation performance of micro-fin tubes

tests were conducted on four micro-fin tubes having different micro-fin geometries and one smooth tube having 9.52mm outside diameter (OD). Two of the micro-fin tubes had 9.52mm OD and the remaining two had 7.0mm OD.The refrigerant used was R22. The experiments were carried out for 90—400kg8226;m-28226;s-1 refrigerant mass fluxes at 7℃ evaporation temperature

15%—20% inlet vapor quality

5—6℃ outlet superheat degrees. The variations of evaporation performance of micro-fin tubes with refrigerant mass flux were obtained. The effects of micro-fin geometry and tube diameter on performance were discussed. The two 9.52mm OD micro-fin tubes yielded 130% and 180% greater heat transfer coefficients than the smooth tube

while the inside surface areas of the two micro-fin tubes were only 40% and 70% greater than that of the smooth tube.