An investigation into the influence of micro structures on nucleate boiling processes

From the prior art it is known that a selective modification of heat transfer surfaces may lead to an improvement of heat transfer rates. For evaporation processes, often the heat transfer surfaces are roughened, coated with porous material or structured by electro-deposition. In this study micro structures are investigated to increase the heat transfer coefficient for heat transfer by nucleate boiling. Applying micro milling and sand-blasting, different micro structures are machined in aluminum plates. A specially developed test bench is used for measuring the heat transfer coefficients for different heat fluxes. The experimental setup and the experimental procedure are described in this paper. By comparing the measurement results it is analyzed as to which structures are most appropriate for heat transfer by nucleate boiling.