Fundamental Evaluation of Thermal Switch Based on Ionic Wind

Abstract

A significant amount of thermal energy (mainly under 200 °C) is wasted in the world. To utilize the waste heat, efficient heat management and thermal switching is required. The basic characteristics of a thermal switch that controls the flow of heat by switching on/off the ionic wind is discussed in this study. The study was conducted through experiments and numerical simulations. A heater made of aluminum block maintained at 100 °C was used as a heat source, and the rate of heat flow to a copper plate placed over it was measured. Ionic wind was induced by corona discharge with a needle placed on the heater. The ratio of heat transfer coefficients was obtained in the range of 3–4, with an energy efficiency of around 10. The heat flux at this condition was approximately 400 W/m2. The numerical simulations indicate that the heat transfer is enhanced by ionic winds, and the results were found to corroborate well with the experimental ones.

Fluidic and Mechanical Thermal Control Devices

“…Go et al. [ 69 ] and Yoshida [ 70 ] respectively achieved switching ratios of SR < 3 and SR < 5 via convection with ionic wind in air with input voltages of U = 4.39–6.15 kV; however, the authors did not discuss the characteristic times.…”

“…The first group includes thermal switches in which an electric field forms a fluidic bridge where two different fluids form a conductive path between the heat source and the heat sink (e.g., electrowetting [ 42,47,76,77 ] and jumping droplets [ 81,82 ] ). The second group includes switches in which only one fluid forms a conductive path between the heat sink and the heat source at all times (e.g., ETC, [ 60 ] electrophoresis, [ 67 ] ionic wind, [ 69,70 ] liquid crystals [ 63–65 ] ); the electric field only changes the fluid properties or forms additional internal convection currents. The first group generally has a higher switching ratio and a longer characteristic time compared to the second group.…”

Special Issue on Plasma Processes for Renewable Energy Technologies

“…Yoshida [6] contributed a paper entitled "Fundamental Evaluation of Thermal Switch Based on Ionic Wind". The author described that a significant amount of thermal energy (mainly under 200 • C) is wasted across the world.…”

The heat dissipation by the multi-needle electrode structure ionic wind generator

“…Under the action of electric field force, the charged particles in gas discharges collide with neutral molecules resulting in the momentum transfer and gas fluid motion, which is the conversion process of electrical energy to mechanical fluid energy [3,4]. With the advantages of quick response for the applied electric field and simple electrode structure, ionic wind shows great application potentials for thermal management [5,6], flow control [7,8], air purification [9,10], auxiliary combustion [11,12], and food drying [13,14]. Compared to the most used cooling techniques, i.e., heat sink and cooling fan, ionic wind heat dissipation can avoid the disadvantages of large size and heavy weight of heat sink, and short lifetime, noise, and vibration of cooling fan with mechanical part, which make it as a promising thermal management technique, especially in small electronic components cooling within tight space [15].…”