Abstract
In order to elucidate the mechanism and characteristics of boiling heat transfer in a micro-channel vaporizer, the experimental investigation of the micro-layer thickness that formed between the heating surface and vapor generated was essentially needed. In this report, the micro-layer thickness was measured applying the laser extinction method for the channel gap sizes of 0.5, 0.3 and 0.15 mm. The process of bubble growth was recorded with a high-speed camera simultaneously. It was confirmed that the gap size, the rate of bubble growth and the distance from the incipient bubble site have an effect on the micro-layer thickness in a micro-channel boiling system. The initial micro-layer thickness increased with increase of the velocity of bubble forefront to moderate value of the velocity. In the region of larger velocity, the thickness was constant for each gap. The distributions of the initial thickness of micro-layer were shown.
