An investigation of surficial conduction heat loss in perfectly aligned micro-wire array

Abstract

Recently, geometrical effects in micro-/nanomaterials have gained great attention of researchers in diverse scientific and engineering fields because unique physical properties can be achieved not only by the micro-/nanosize effects of materials but also by adjustment of the geometrical parameters. In this work, we investigated heat-transfer in a perfectly aligned microwire array structure. When the structure has a very narrow gap (g) between the wires, which is less than twice the mean free path of an ambient medium (g < 2 λ medium), there is a significant suppression of conduction heat-loss due to the reduction of the "molecular diffusion," resulting in the improved power-efficiency in joule-heating characteristics. To clearly understand the suppressed conduction heat-loss with regard to the gap reduction, we performed analytical calculation and finite-element-method (FEM) simulation. To experimentally investigate the phenomenon, we develop a setup that is a combination of a microstructure having various gaps and an air-pressure controllable chamber. Through the experiment, we verified that a remarkable improvement of joule-heating operation can be achieved with the structure having very small gaps (g < 2 λ medium) due to the suppression of conduction heat-loss.