Enhanced nucleate boiling and CHF on a small horizontal plate under ionic jet impingement

The application of a strong electric field within a dielectric medium can produce a jet-like motion of ionized liquid from a high-voltage electrode to a grounded heated plate. Ionic jet impingement on the upper surface of a horizontal plate where boiling is occurring significantly modifies the boiling curve. The effect of ion injection on saturated boiling heat transfer, specifically on boiling inception, nucleate boiling, and CHF, in a small-size sample with a single point-electrode configuration, has been experimentally investigated; the working fluid is FC-72. Significant heat transfer enhancement has been observed for the entire nucleate boiling curve. Besides, CHF has been delayed to higher heat fluxes (up to a 40% increase) by means of the impinging ionic jet. This active technique requires a negligible power input (in the order of a few milliwatts) for the ionic current. A focus on the influence of the electrical parameters on the phenomenon has been performed and preliminary results are presented. Further tests and modeling effort are needed to optimize this very promising technique.