Experimental study on boiling in micro-chambers

The present paper describes an experimental study on boiling of water in micro-chambers. The chambers were fabricated by machining a circular disk on the surface of a copper substrate using a precision milling machine and then covering the disk with a transparent lexan plate for visual observation. The diameter of the disk was about 12 mm and two chamber depths (50 μm and 125 μm) were used. Temperatures in the substrate at different distances from the bottom of the micro-chamber as well as the lexan plate at mid-thickness were measured using micro-thermocouples inserted from the side of the specimen. Boiling in the micro-chamber was accomplished by heating the metal substrate from below using an electric plate heater. The boiling process in the micro-chamber was observed and recorded using a Solid state CCD camera attached to a microscope. The video images were analyzed together with the transient substrate and cover plate temperature measurements. Some initial observations and results are presented.