R133zd(E) flow boiling inside a 4.3mm ID microfin tube.

Abstract

This paper explores the heat transfer and fluid flow characteristics of a new low-GWP refrigerant R1233zd(E) during flow boiling inside a mini microfin tube with internal diameter at the fin tip of 4.3 mm. The microfin tube is brazed inside a copper plate, electrically heated from the bottom. Several T-type thermocouples are inserted in the wall to measure the temperature distribution during the phase change process. In particular, the experimental measurements were carried out at constant mean saturation temperature of 30°C, by varying the refrigerant mass velocity between 100 kg m-2 s-1 and 300 kg m-2 s-1, the vapor quality from 0.2 to 0.95, at four different heat fluxes: 15, 30, 60, and 90 kW m-2. The experimental results are presented in terms of the two-phase heat transfer coefficient, onset of dryout vapor quality, and frictional pressure drop as a function of the operating test conditions.