0017-9310/$ see front matter 2011 Elsevier Ltd. A doi:10.1016/j.ijheatmasstransfer.2011.04.028 ⇑ Corresponding author. E-mail addresses: [email protected], maa59@ URL: http://www.mohsenakbari.com (M. Akbari). This paper outlines a novel approximate model for determining the pressure drop of laminar, singlephase flow in slowly-varying microchannels of arbitrary cross-section based on the solu...