Numerical Investigation on Laminar Microconvective Liquid Flow With Entrance Effect and Graetz Problem due to Variation in Thermal Properties.

This work deals with the analysis of forced convection in single-phase laminar flow of liquid through microsized circular geometry with a diameter of 100 × 10−6 m. The problem with hydrodynamically and thermally developing flow in the entrance region with no-slip, no-temperature jump and constant wall heat flux boundary condition is numerically studied. Two-dimensional (with axisymmetry) simulation is carried out to understand the effect of fluid property variations on flow development and heat transfer. Pure continuum-based governing equations are solved to predict the significance of momentum and energy transport due to temperature-dependent viscosity and thermal conductivity variation, respectively. The radial inward flow is induced due to temperature-dependent density variation that sharpens the axial velocity profile. The investigation also analyzes the change in Nusselt number with locations in the channel for Graetz problem with uniform heating condition. The flattening of axial velocity profile, radial temperature profile, and inward radial flow influences the heat flow characteristics. The investigations in computational domain show that Nusselt number in thermal entrance region deviates from constant properties solution due to scaling effects. [ABSTRACT FROM AUTHOR]