Simulation based investigation of Nusselt number and Poiseuille number in helical microchannels

Abstract

Simulation based work carried out in order to understand the thermohydraulic characteristics of fluid flow in helical microchannel, with circular cross-section, that is subjected to constant heat flux is detailed in this work. Water is used as the fluid in this study and the study is carried out for Reynolds number ranging from 50 to 500. The helical path of the fluid increases the heat transfer coefficient and pressure drop for a specific Reynolds number in comparison with that in a straight microchannel. The increase in heat transfer coefficient and pressure drop associated with the helical microchannel manifests as increased Nusselt number and Poiseuille number. At Reynolds number of 50, the Nusselt number of the helical microchannel is 1.36 times higher than that of the straight microchannel while at Reynolds number of 500, this enhancement increases to 2.33. Regarding Poiseuille number of helical microchannel, it is higher than that of the Poiseuille number of straight microchannel by 1.02 and 1.72 at Reynolds number of 50 and 500, respectively. It is identified from this study that by shifting from straight microchannel to helical microchannel, the enhancement in Nusselt number is higher than the associated penalty, i.e. increase in Poiseuille number.

Keywords

• Heat transfer enhancement
• Helical microchannel
• Nusselt number
• Poiseuille number