Experimental investigation of heat transfer and pressure drop during condensation of R134a in multiport flat tubes

Abstract

This paper presents the results of an experimental investigation on heat transfer and pressure drop characteristics for R134a in multiport flat tubes (MPFT). In order to perform a fundamental analysis, an experimental facility has been set up to determine both the heat transfer coefficient and the pressure drop value in the two-phase flow regime inside extruded MPFT (d=0.91−0.77mm) with either rectangular channels or including an axial fin structure. The operating parameters have been varied within a broad range to ensure a high degree of reliability and comparability to heat transfer and pressure drop correlations. A very good agreement of the pressure drop data with the Friedel (1979) and Jige et al. (2016) correlations can be confirmed. The heat transfer coefficient can be predicted well for the MPFT with rectangular channels using the Jige et al. (2016) correlation, but only poor agreement can be achieved for the MPFT including the fin structure for all correlations taken into consideration.