Numerical prediction of heat transfer and pressure drop in three-dimensional channels with alternated opposed ribs

Nusselt numbers and friction factor of a ribbed channel have been calculated for several Reynolds numbers and geometric parameters, by the mean of three-dimensional incompressible computational fluid dynamics. The geometry is a rectangular duct with streamwise-periodic transverse rectangular ribs, alternated on its two smaller walls. Reynolds numbers from 75 to 2000 have been investigated. Pressure drop is found to increase monotonically with Re, whereas heat transfer is enhanced only when Re is greater than a critical value. Heat transfer enhancement interpretations, such as the interruption of developed thermal boundary layers and vortex shedding phenomena are discussed.

► We present CFD computations of a three-dimensional ribbed channel.
► Nusselt numbers and the friction factors are predicted for several Reynolds numbers.
► Pressure drop is found to increase for all Re.
► Heat transfer is enhanced when Re is greater than a critical value.
► Heat transfer intensification is due to oscillatory and turbulent phenomenon.