A study of heat transfer enhancement via corona discharge by using a plate corona electrode

Abstract

This paper is concerned with the corona discharge used to enhance heat transfer. Both theoretical and experimental procedures are employed. To examine the heat transfer resulting from corona discharge, a thin plate is employed as the corona electrode and a heated plate is grounded to form the collecting electrode. Experiments show that the heat transfer coefficient at the center of the heated plate is increased by a factor in the range 2.6-4.8 times comparing with natural convection. Optical images reveal that corona discharge occurs at the two side corners of the plate electrode when the corona voltage is low and a bluish sheet of discharge issuing from the front edge of the electrode is visible at sufficiently high voltages. Comparison between predicted temperatures and measurements indicates that significant differences exist at low corona voltages and good agreement is obtained when the voltage is high enough. This result is mainly attributed to the 2-D assumption employed in the simulation and the heat loss appearing in the experiment. The corona discharge is stronger for small electrode gaps. However, the corona voltage allowed before formation of the electrical spark is higher for large electrode gaps, leading to better heat transfer. (C) 2017 Elsevier B.V. All rights reserved.