Impact of Periodically Generated Hydrodynamic Disturbances on the Condensation Efficiency of R134a Refrigerant in Pipe Mini-Channels

Abstract

This article discusses an experimental analysis of the influence of periodically generated external hydrodynamic disturbances on the condensation process of the R134 refrigerant in circular pipe mini-channels. The investigations were carried out for horizontal single mini-channels with internal diameters in the range of d = 0.64–3.30 mm. It was established that within the range of frequencies under investigation (f = 0.2–5 Hz), i.e., the frequencies at which disturbances are generated, the disturbances exert an influence on the structure of the characteristic condensation areas in the mini-channel. The disturbances have an unfavorable impact on the reduction of the two-phase length of specific condensation and a reduction of the heat flux in this area. The heat removal intensity in the two-phase area has an impact on the efficiency of the operation of a compact condenser. The impact of more important parameters on this efficiency is discussed.