Wall and packing shear stresses and turbulence effect with steam methane reforming

Abstract Turbulence distorts the flow and disturbs the transport processes within a packed bed. A statistical comparison of the results from three hundred and sixty simulations of steam methane reforming (SMR) employing 30 different pressure drop correlations, three different inlet pressures, and two inlet temperatures with a cross sectionally averaged turbulence‐free model and a cross sectionally averaged Reynolds averaged Navier–Stokes turbulence model under industrial operating conditions indicates that turbulence reduces methane conversion and hydrogen yield. The knowledge of the wall shear stress is important in many engineering practices. A relation for computing the wall shear stress in packed beds directly from the bulk flow data for both the turbulence and turbulence‐free models is presented and the axial distribution of the wall shear stress and also the mean packing shear stress are reported for steam methane reforming. Unlike the logarithmic law of the wall, the wall shear stress relation presented here is directly derived from the averaging of the Navier–Stokes momentum equation without any reference to the flow other than the no slip condition in the near‐wall boundary layer. The statistical analysis of the wall shear stress shows that turbulence exerts no influence on the wall shear stress.