The effect of viscous forces on heat and mass transfer in systems with turbulence promoters and in packed beds

Abstract The pressure drop per unit length in flow through packed beds or past turbulence promoters is the sum of viscous and kinetic losses: Δ P L = aμV + bϱV2. The transfer rates in such systems (dependent only on the viscous forces at the transfer surfaces) are correlated by and may therefore be predicted from measurements of the total surface area per unit volume S, the voidage ϵ and the parameter a, which together form an ‘equivalent diameter’ S/aϵ in the modified Reynolds number Re*.