We　provide　three-dimensional　numerical　simulations　of　conjugate　heat　transfer　in　the　newly　proposed　microchannels　with　different　structural　parameters.　The　structural　parameters　include　the　lengths　and　widths　of　the　constant　cross-section　region　and　the　arcuate　region.　The　effects　of　structural　parameters　on　pressure　drop　and　thermal　resistance　are　presented.　For　the　first　part　of　the　effect　analysis,　we　study　the　fluid　flow　and　heat　transfer　mechanism　of　the　microchannel　with　aligned　fan-shaped　reentrant　cavities　in　detail,　which　can　attribute　to　the　interaction　of　the　increased　heat　transfer　surface　area,　the　redeveloping　boundary　layers,　the　jet　and　throttling　effect　and　the　slipping　over　the　reentrant　cavities.　As　to　the　second　part　of　the　present　analysis,　the　effects　of　two　design　structural　parameters　on　fluid　flow　and　heat　transfer　of　the　new　microchannel　are　individually　prescribed　and　the　two　suitable　ranges　of　structural　parameter　are　found　for　the　optimum　geometric　configuration.　(C)　2010　Elsevier　Masson　SAS.　All　rights　reserved.