Mixed Convective Heat Transfer

In this research, I conducted a two-dimensional (2D) numerical study to explore fluid flow and heat transfer within a rectangular channel featuring staggered ribs on both walls. These ribs are designed to enhance heat transfer by creating complex flow dynamics, and I examined how thermal buoyancy—where heated fluid rises due to temperature differences—affects these patterns under various conditions.

The study focuses on a Newtonian fluid, with Reynolds numbers (indicating flow characteristics) between 50 and 120, and a constant Prandtl number of 0.7, which relates fluid viscosity to thermal diffusivity. Heat transfer, influenced by buoyancy, is characterized using Richardson numbers from 0 to 2, representing scenarios from negligible to moderate buoyancy effects.

I used the lattice Boltzmann method, a numerical approach well-suited for capturing intricate flow behaviors, to solve the unsteady flow and heat equations. This computational strategy was validated against established test cases and benchmarked with existing data. Through streamlines and isotherm patterns, I analyzed the flow and heat transfer characteristics across different flow speeds (Reynolds numbers) and buoyancy strengths (Richardson numbers). The results reveal how thermal buoyancy impacts flow behavior, heat distribution, drag forces, and localized as well as average heat transfer, providing insights into optimizing heat transfer in similar ribbed channel systems.