Analysis of the Polarity Influence on Nucleate Pool Boiling Under a DC Electric Field
An experimental study of the action of an intense electric field on the pool boiling of n-pentane is presented. By the application of a 25 kV/cm electric field strength, a threefold heat transfer enhancement is obtained. The effect of the electric field polarity has been researched. In nucleate boiling, the negative polarity allows to obtain a heat transfer enhancement, which is better than the one obtained in positive polarity. However, in natural convection and near the critical heat flux, the polarity of the electric field has a low influence on the heat transfer. The interpretations of the observed results are based on the action of the electric field on the boiling phenomenon and more particularly on the analysis of the electric field distribution between the electrodes. The influence of the space charge injection and the effect of the temperature on the electric field distribution have been investigated. The results obtained in the two cases of polarity are discussed in terms of effects of electrical and thermal phenomena on the distribution of the electric field between the electrodes.