Hybrid micro-nano structured thermal interfaces for pool boiling heat transfer enhancement

Boiling heat transfer from hybrid micro-nano structured thermal interfaces has been studied experimentally using PF5060 and deionized water as working fluids for the range of saturation temperatures T-sat between 35 degrees C and 60 degrees C. Various enhancement structures were fabricated using surface micromachining in silicon. The performance of the smooth and roughened silicon surfaces, bare and fully coated with carbon nanotubes (CNTs), the silicon-etched as well as CNTs-based pin-fin arrays, and the 3D microstructures have been studied in detail. The highest heat fluxes were obtained using the 3D microstructure without CNTs-these are 27 and 130 W/cm(2) for PF5060 and water, respectively. Experimental results indicate that use of the CNT-enabled, purely nano-structured interfaces appear to improve boiling heat transfer only at very low superheats, as compared to the smooth surfaces. (c) 2005 Published by Elsevier Ltd.