Dry State in a Contact Area of a Boiling Bubble on a Heating Surface

Abstract

A dry part in a contact area of a boiling bubble on a wetted heating surface was observed by experiment using an electro-conductive glass. And size of the dry part was measured in the experiment, and it was compared with calculation based on vaporization by heat transfer through a thin liquid layer in the contact area of the bubble. And it was found that area of the dry part was roughly proportional to superheat of the heating surface and contact time of the bubble. And ratio of area of the part to total contact area in the heating surface was about 10% for any heat flux except very high and verly low heat flux at an atmospheric pressure in water of suturation.