The two-phase flow-condensation heat transfer experiment of R134a inside the micro-fin tube was operated on the test bench

the influence of working conditions and micro-fin tube structural parameters on the pressure drop was studied

and its correlations were also used to predict the pressure drop inside the tube in this study. The experimental results show that the pressure drop is positively correlated with mass flux and fin helical angle; however

they are negatively correlated with condensation temperature and Re of cooling water. Correlations of Cavallini et al.

Haraguchi et al.

and Pierre have good predictive effects on the pressure drop with an average prediction error of less than 17%

while the correlation Goto et al. overestimates the pressure drop. Based on the pressure drop experimental data of R134a

the functional relationship between Фv/Фl and Xtt was fitted again and referred to the computing mechanism of Goto et al. for correlation. Then

a new correlation for predicting the pressure drop inside the tube is put forward

and statistic test shows that the prediction error of the new correlation is within ±30% and the average prediction error is less than 10%.