A second look at electrokinetic phenomena in boiling

Abstract

In the article by V. Asch [J. Appl. Phys. 37, 2654 (1966)], experiments were performed to study the influence of an electrostatic field on nucleate boiling of Freon-113(R-113). We have found that Asch might not have properly considered the effects of his experimental setup and therefore came to incorrect conclusions concerning electrophoretic and dielectrophoretic forces. Asch's analysis of the electric field distribution led him to conclude that the dielectrophoretic forces were small, however, we show in this article that, in general, there are strong dielectrophoretic forces in the vicinity of the heater wire. This article presents the results from a set of experiments performed with an apparatus similar to that of Asch's with test fluids of R-113 and FC-72. The experimental results show that vapor bubbles can be attracted to either the anode or cathode depending on the potentials with respect to the heater wire on which the boiling takes place. This is contrary to the results obtained by Asch which led him to conclude that the bubbles were always attracted to the anode. The bubble movement appears to be the result of a combination of dielectrophoretic forces (which are very strong but highly localized), electrophoretic forces, and bulk electroconvective flow. Furthermore, the combined effects of these forces away from the wire can lead to unstable behavior. © 1996 American Institute of Physics.