Laminar Thermally Developing Flow in Elliptical Minichannels with Isoflux Wall

Abstract

Laminar convective heat transfer for the thermally developing flow in elliptical minichannels is numerically investigated under constant heat flux with high thermal conductivity materials (H1) and low thermal conductivity materials (H2) boundary conditions. The effects of the Peclet number and the aspect ratio on both the local Nusselt number and the thermal entrance length are presented graphically. The Peclet number is a key parameter for heat transfer in the developing flow. The local Nusselt number is a decreasing function of the Peclet number, especially for the Peclet number less than 500, where a sharp decline can be observed. As the aspect ratio decreases, the Nusselt number increases for the H1 boundary condition but diminishes for the H2 boundary condition. Generalized correlations for the thermal entrance length and the local Nusselt number are proposed for the design and optimization of elliptical minichannel heat sinks.