Abstract
In a condenser the thickness of the liquid condensate film covering the cooled surface constitutes a resistance to the heat transfer. By establishing a non uniform electric field in the vicinity of the condensation surface the extraction of liquid from the surface can be realized. The liquid film thickness is reduced and as a result the condensation heat transfer coefficient is increased. A vertical single tube condenser is built to investigate the electrohydrodynamically enhanced condensation heat transfer both qualitatively and quantitatively. R- 1 13 is used as the working fluid. Based on visual observation for various sample electrode configurations the electrode design is optimized with respect to the amount of liquid extracted from the condensation surface. Heat transfer results are presented for the optimum electrode design. The UA-value of the condenser is enhanced by up to 23 % by realizing the liquid extraction phenomenon. This corresponds to a much higher increase in the condensation heat transfer coefficient since only the term representing the condensation heat transfer coefficient in the equation for the UA-value was affected. The necessary electric power input is found to be negligible, representing less than 0. 004 % of the exchanged heat.
Wawzyniak, Markus (1993). Electrohydrodynamically enhanced condensation heat transfer. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1993 -THESIS -W356.