Condensation heat transfer of R-134A flow inside helical pipes at different orientations

Abstract

This paper presents an experimental investigation of condensation heat transfer of alternative refrigerant R-134a flowing inside a helical pipe with cooling water through the concentric annular passage in a counter-flow direction. The experiments were conducted with the helix axis of the test section in horizontal, vertical, and inclined orientation directions, respectively. The mass flow flux for R-134a ranges from 100 to 400 kg/m 2 s and the Reynolds number of cooling Natter ranges from 1500 to 10000. The results demonstrate the orientation of helical pipe has a significant effect on both refrigerant-side heat transfer and overall heat transfer coefficients.