Effect of Prandtl number on internal convective heat transfer in laminar single-phase pulsating flows

In this paper, heat transfer during simultaneously developing singlephase laminar flow inside a pipe has been investigated numerically. A two dimensional axisymmetric model of a circular mini-channel is used, with a constant wall temperature boundary condition. In the present simulations, flow Reynolds number (Re) and amplitude ratio (A) are kept constant to 200 and 0.2, respectively. The variable quantities are imposed pulsating frequency (f) or nondimensional frequency (Womersley number, Wo) and Prandtl number (Pr). Study is conducted for three different imposed flow frequencies of 5 Hz, 15 Hz and 25 Hz respectively while Prandtl number values are varied from 2.43 to 3404. These flow parameters can be grouped together to form different time scales which are important to explain the heat transfer behavior in laminar single-phase pulsating flow. It is observed that for the range of frequency (f) and Prandtl number (Pr) used in present work, change in heat transfer is marginal which is of no practical significance. Enhancement of heat transfer coefficient due to such periodic pulsatile internal flows, over and above the non-pulsatile regular flow conditions, is questionable, and at best, rather limited.