Experimental and analytical study of time varying electrical fields and their effect on convective boiling heat transfer.

摘要

The effect of time varying electrical fields on steady state convective boiling as well as transient convective boiling was investigated. Through a wide range of frequencies and wave forms tested, the DC negative wave form was seen as the most effective in enhancing the heat transfer system used in this investigation. Three different mixtures of conducting ethanol and insulating pentane were also tested. From the observations completed in this research it was seen that a mixture of 40% ethanol and pentane allowed for the largest temperature drop by application of the electrical field. This was observed for multiple heat and mass flux conditions. High speed video was used to show the complexity of the electrical field effect for the 7.5% volume fraction of ethanol, and by force deduction, it was seen that a negative charge distribution was present in the fluid. From current data it was seen that this was due to the temperature gradient in the fluid, interface gradient between the liquid and vapor phase, and the species gradient between the two mixtures.