Experimental Analysis and CFD Simulation of Pressure Drop of Carbon Dioxide in Horizontal Micro Tube Heat Exchangers

Abstract

The condensation of carbon dioxide in single horizontal micro tube condensers of inner diameter ranged from 0.6 mm up to 1.6 mm over
mass flow rates from 2.5*10-5 to 17*10-5kg/s and vapor qualities from 0.0 to 1.0 is studied experimentally. The inlet condensing pressure is
changed from 33.5 to 45 bars. The saturation temperature ranged from -1.5 oC up to 10 oC.CFD analysis of two phase flow of refrigerants
inside a smooth horizontal tube is carried out under adiabatic conditions using commercial CFD software, FLUENT for different mass flow
rates and different saturation temperatures. The values of pressure drop obtained from the simulation of carbon dioxide are compared with
three different prediction correlations and the pressure drop experimental data resulted from this study. The Muller method gave the best fit
to the experimental results with average standard deviations of 6.4%, followed by CFD model with 8.9% then Friedel and Gronnerud
methods with 12.1% and 17.3%, respectively