Two-phase flow condensation pressure drop of R14 in a horizontal tube: Experimental investigation and correlation development

Tetrafluoromethane (R14)is an important fluid in three-stage-cascade refrigeration and mixed-refrigerant Joule-Thomson refrigeration (MJTR). In this work, an experimental investigation on condensation pressure drop of R14 in a horizontal smooth tube with inner diameter of 4 mm was carried out. Experiments were implemented at mass fluxes from 150 to 650 kg/(m² s), saturation pressures from 1 to 3 MPa and heat fluxes from 8.3 to 28.2 kW/m² over the entire range of vapor quality. The effects of heat flux, mass flux, saturation pressure and vapor quality were analyzed and discussed. In addition, the frictional pressure drops were compared with twenty-nine well known frictional pressure drop correlations. An improved frictional pressure drop correlation was deduced and predicted R14 experimental data well with a mean absolute relative deviation of 12.18%. Finally, 2317 data points from nineteen published literature were adopted to evaluate the predictive ability of this new model. It achieves a satisfactory predicting result with a mean absolute relative deviation of 17.39% and 87.26% of the experimental data within the deviation bandwidth of ±30%.