Numerical Investigation of Air Forced Convection in Channels With Transverse Ribs
Heat transfer in fluids is very important in many industrial heating and cooling equipments. Convective heat transfer can be enhanced passively by changing flow geometry, boundary conditions or by increasing thermal conductivity of the fluid. Another possibility for increase heat transfer with fluid is to employ extended surfaces. When fluid flows in a channel, transversal ribs works as fins and break the laminar sub-layer the laminar sub-layer creating local wall turbulence. As a consequence the presence of the ribs can significantly augment pressure drop. In this paper a numerical investigation is carried out on forced convection in a channel with constant flux applied on the external walls. The fluid is air and an incompressible model is employed. Ribs of the same material of the channel walls are introduced and several shape and arrangement are analyzed. The investigation is accomplished by means of the commercial code Fluent. A turbulence model is used. Results are presented in terms of temperature and velocity fields, average heat transfer coefficients and pressure drops. The aim of this study is to find the shape and arrangement of ribs such to give high heat transfer coefficients and low pressure drops.