Experimental study of the nonisothermal gas-liquid two-phase heat transfer characteristics in a rectangular helical channel

Abstract

In this study, the nonisothermal two-phase heat transfer in the rectangular helical channel is proposed to effectively reduce the heat transfer losses in the single screw expander. The interphase heat transfer rate and temperature distribution of the nonisothermal gas-liquid two-phase flow in the rectangular helical channel are experimentally investigated under different gas-liquid flow rates, gas phase temperatures, and dimensionless pitch and curvature. The results indicate that increasing Re_l and Re_g will enhance the interphase heat transfer rate, and the effect of Re_l on the heat transfer rate is gradually weakened at a larger Re. A further increase in Re_g obviously increases the interphase heat transfer rate, but it has little influence on the peak temperature and temperature distribution of the gas. The interphase heat transfer rate is much higher for the helical channel with γ = 0.145. A maximum reduction of 28.5 J/s in the interphase heat transfer rate is obtained by decreasing the curvature ratio of the helical channel from 0.145 to 0.129. Furthermore, a maximum reduction of 36.5 J/s in the interphase heat transfer rate is obtained by decreasing the dimensionless pitch of helical channel from 0.9 to 0.5.