Pool boiling of ethanol on surfaces with parallel microchannels

Abstract

The paper presents investigations into pool boiling heat transfer for open minichannel surfaces. The experiments were carried out with saturated ethanol at atmospheric pressure. Parallel microchannels fabricated by machining were about 0.2, 0.3 and 0.4 wide and 0.2 to 0.5 mm deep. The measurements were performed with increasing heat flux and variable geometric parameters of the minichannels. The image acquisition speed was 493 fps (at resolution 400 x 300 pixels with Photonfocus PHOT MV-D1024-160-CL camera) and an EX-FH20 (Casio) camera was used to record the images of the entire surface of the specimen. The analysis of boiling curves for the tested surfaces does not give an unambiguous response to the influence of geometrical parameters, i.e. the height of the microchannels on the heat transfer process.