Heat and flow investigation of NOVEC649 refrigerant condensation in pipe minichannels

Abstract

This paper presents the experimental research results of Novec649. The refrigerant was condensed in 4 pipe minichannels with hydraulic diameters of dh = 2.5, 2.0, 1.2 and 0.5 mm. This refrigerant is a low-pressure fluid with an ODP = 0 and a GWP = 1. The aim of the study was to determine average and local values of the heat transfer coefficient α and the pressure drop (Δp/L) for the entire range of the vapour quality (x = 1 ÷ 0) of Novec649 in the pipe minichannels. The tests were carried out on a specially designed and built laboratory test stand, which was described in this paper. The influence of the mass flux density G, the vapour quality x and the internal channel diameter dh on the studied parameters was illustrated. These experimental results were compared with the calculation results based on the Bohdal et al. [1] correlations.