Seminar

ENGINEERING HDR SEMINAR SERIES (36/2015):Thermal performance of ionic wind under various environmental conditions

Lee Jun Rong


Date: 2015-07-29
Time: 11:00 to 12:00
Venue: 5-4-22 (Meeting room 1), Building 5, Level 4


Abstract

Ionic wind is the movement of air induced between a sharp pointed electrode and a grounded electrode under the presence of high potential difference. Today, the ionic wind has become a topic of research interest due to its compact size and the noise-free nature as demonstrated by passive cooling devices. Up to date, there is no satisfactory investigation on the exact influence of the environmental conditions such as relative humidity and gas pressure on the generation of ionic wind and its subsequent effects on its cooling capabilities. This research aims to investigate the behaviour and the convective heat transfer enhancement by the ionic wind under various environmental conditions. The current research project is initialised by investigating the effects of relative humidity on the generation of positive and negative ionic wind as well as their convective heat transfer enhancement. In general, the Reynolds number, Re for both positive and negative ionic wind increases with the increase of relative humidity. However, at lower supplied voltage, the negative ionic wind is observed to have higher Re compared to that of the positive ionic wind, while for high supplied voltage, no significant difference is noted. In contrast to this increase in Re, the heat transfer enhancement by both positive and negative ionic wind actually decreases with the increase of relative humidity, suggested to be due to the decrease in thermal conductivity of air at high humidity. As for the investigation on the effect of air pressure, comparison of the ionic wind characteristic is made at 0.7, 1 and 1.5 bar air pressure. The Re of both positive and negative ionic wind is found to be higher at 1 bar air pressure. However, the heat transfer enhancement for positive ionic wind is found to be higher at 1.5 bar air pressure instead of 1 bar, which has the higher Re due to better convective coefficient at high pressure. As for negative ionic wind, the heat transfer enhancement is better at 1 bar air pressure as the Re is significantly higher at high supplied voltage. Further investigation is to be conducted by using different level of air pressure to further validate the conclusion of the results. 

About the Speaker

Mr. Lee Jun Rong graduated with Bachelor of Engineering (Mechanical) from Monash University Malaysia in 2013. He then continued to pursue his postgraduate studies under the supervision of Dr. Lau Ee Von and Dr Kenny Tan in 2013. His research focuses on the characteristics of ionic wind and its thermal performance under different environment.