In-tube Evaporation Pressure-drop Characteristics of R290 and R404A

Abstract

The experimental results of in-tube evaporation pressure-drop of R290 and R404A in the horizontal smooth tube and the horizontal microfin tube were compared with calculation results by Lockhart & Martinelli pressure-drop correlation,respectively.Moreover,based on the experimental data of R290 and R404A,Lockhart & Martinelli pressure-drop correlation was modified adequately.For R404A.the correlation shows good agreement with experimental values with mean deviation of-11.52% for the smooth tube and-17.86% for the microfin tube.Lockhart & Martinelli pressure drop correlation can also predict well the in-tube evaporation pressure-drop of R290 for the smooth tube with mean deviation of-21.68%.However,2.06 to agree well with the experimented data should multiply the predicted value for the microfin tube by Lockhart & Martinelli correlation,and the mean deviation is 2.37%.