The objective of the research program is to investigate experimentally and semi-theoretically nucleate boiling from a copper-graphite composite surface. The composite (under development by SPARTA, Inc.) consists of ultra-high thermal conductivity graphite fibers consolidated in a copper matrix. The composite has a high thermal conductivity in the fiber direction which is several times those in the other directions. Due to the size of the fiber, it could significantly enhance the nucleation site activity. The proposed research will determine the heat flux, site population density, bubble growth rate, bubble departure frequency and bubble departure size. This project is a cooperative effort of the University of Michigan and SPARTA, Inc. The Sparta's Copper/Graphite composite has been used as the higher temperature material in the nose cone of the NASA space shuttles. Due to its large number of very thin graphite fibers, the composite is expected to remove a large amount of heat per unit area in the form of nucleate boiling. If the concept is experimentally verified, then the use of the composite in industry will be very broad, for example, in the cooling of electronic units. This research is a proof-of-concept type study for the verification of its boiling performance.
