CH-95-14-1 -- Compound Enhancement of Boiling Heat Transfer of R134a in a Tube Bundle PDF

Heat transfer enhancement of R134a in a tube bundle for a pool boiling regime was studied experimentally utilising the electrohydrodynamics (EHD) technique. A laboratory-scale tube bundle utilising commercially available 40-fins-per-inch (40-fpi) enhanced tubes was used in the experiments. R134a was chosen as the working fluid in all of the experiments. The results of the experiments demonstrated the applicability of the EHD technique for heat transfer enhancement in tube bundles. A nearly threefold enhancement in the boiling heat transfer coefficient of the bundle was obtained with maximum EHD power consumption of 1.2% of the bundle heat transfer rate. The effect of electric field polarity was studied and was found to have no pronounced effect on the enhancement mechanism for the application at hand.

KEYWORDS: year 1995, boiling, heat flow, refrigerants, R134a, tubes, experiment, finned tubes, laboratory testing