Laser Interferometric Investigation of the Microlayer Evaporation Phenomenon

Abstract

An experimental investigation is presented in which the growth and evaporation of the microlayer underlying a bubble forming on a glass heater surface has been studied using laser interferometry and high speed photography. The results presented for a single bubble indicate that the microlayer thickness is of the order of 5 μm. Subsequent analysis of these results confirms that the microlayer evaporation phenomenon is a significant heat transfer mechanism, representing approximately 25 percent of the total nucleate boiling heat transfer rate for the conditions investigated.

A depletable micro-layer model for nucleate pool boiling

“…50 The existence of this thin liquid film, called the micro-layer, was confirmed experimentally using optical interferometry by Sharp [27] and Jawurek [28] in the 1960's. These pioneering works were followed by several others [29][30][31], all with similar conclusions. These works revealed that the thickness of the micro-layer is of the order of few micrometers.…”

Physical mechanisms of heat transfer during single bubble nucleate boiling of FC-72 under saturation conditions. II: Theoretical analysis

“…Judd and Hwang [12] used Voutsinos and Judd [20] experimental results (on dichloromethane) for the initial microlayer thickness (1-6 lm depending on the surface heat flux) to calculate the total microlayer volume. Also, they determined the nucleation site density (n = N/A T ) experimentally.…”

Microlayer structure in nucleate boiling of water and ethanol at atmospheric pressure

“…Jawurek [5] measured the microlayer thickness to be 0.5 lm for ethanol on a glass surface by using a similar method. Furthermore, by using a laser light source, Voutsinos and Judd [6] measured the microlayer thickness in dichloromethane to be in the range 1-6 lm. They found that the thickness increased with increasing distance from the incipient bubble site.…”