Micro-structured rough surfaces by laser etching for heat transfer enhancement on flush mounted heat sinks

Abstract. The aim of this work is to improve heat transfer performances of ush mounted heat sinks used in electronic cooling. To do this we patterned 1.23 cm2 heat sinks surfaces by micro- structured roughnesses built by laser etching manufacturing technique, and experimentally measured the convective heat transfer enhancements due to dierent patterns. Each roughness diers from the others with regards to the number and the size of the micro-ns (e.g. the micro- n length ranges from 200 to 1100 m). Experimental tests were carried out in forced air cooling regime. In particular fully turbulent ows (heating edge based Reynolds number ranging from 3000 to 17000) were explored. Convective heat transfer coecient of the best micro-structured heat sink is found to be roughly two times compared to the smooth heat sinks one. In addition, surface area roughly doubles with regard to smooth heat sinks, due to the presence of micro-ns. Consequently, patterned heat sinks thermal transmittance [W/K] is found to be roughly four times the smooth heat sinks one. We hope this work may open the way for huge boost in the technology of electronic cooling by innovative manufacturing techniques.