EHD-enhanced boiling coefficients and visualization of R-134a over enhanced tubes

In all earlier study by the authors, the applicability of the EHD technique for augmentation of pool boiling heat transfer of R-134a in a tube bundle was demonstrated. This paper reports additional experiments involving optimization of the electrode/heat transfer surface geometry as well as flow visualization studies that provide improved understanding of the EHD-enhanced pool boiling heat transfer in a tube bundle. Utilizing the flow visualization studies, it is demonstrated that combined electroconvection and improved nucleate boiling dynamics give rise to the augmented heat transfer coefficients.