Ｕベンドを有する二重管形凝縮器に関する研究　非共沸混合冷媒Ｒ１１４／Ｒ１１３による実験

摘要

Local heat transfer and pressure drop measurements were made during condensation of a nonazeotropic refrigerant mixture R114/R113 in the annulus of a double-tube coil consisting of four straight sections and three U-bends. The inner tube was a corrugated tube having soldered wire fins. The vapor phase mass transfer coefficient exhibited a sawtooth behavior, with those of the U-bends larger than those of the straight sections. The frictional pressure gradient data agreed well with a previously developed empirical equation for the condensation of pure refrigerants. A prediction method for the condensation heat transfer rate was proposed on the basis of the correlations of the vapor phase mass transfer coefficient and heat transfer coefficient of the condensate film. The heat transfer data were correlated by the present prediction method to a mean absolute deviation of 12.9%.