OR-94-10-3 -- In-Tube Boiling Heat Transfer Enhancement of R-123 Using the EHD Technique PDF

The applicability of the electrohydrodynamic (EHD) technique for in-tube boiling heat transfer enhancement of R123 was investigated experimentally. The test rig consisted of a tube-in-tube heat exchanger with hot water flowing in the outer tube and the test refrigerant flowing in the inner tube. The experiment utilised a stainless steel cylindrical electrode with an outer diameter (OD) of 3mm (0.118 in.) placed coaxially in the test section, which was a 1.22m (4 ft) long, smooth, stainless steel tube with an inner diameter of 9.4mm (0.37 in.). The experiments were performed as a function of parametric values of inlet quality, heat flux, and mass flux. It was found that R123 exhibits an excellent response to the EHD effect. An increase in the heat transfer coefficient of as high as 550% was obtained when compared to the base case (absence of EHD effect). In the worst case, the electrical power consumption penalty was found to be less than 0.27% of the corresponding test section's heat transfer rate.

KEYWORDS: heat flow, refrigerants, R123, boiling, testing, experiment, heat exchangers, stainless steel, heat transfer coefficient, flow rate, measuring