Table . Heat and C 4 H 10 species mass flow integrated over the particle volume, the fluid and solid side of the interface and between domain inlet and outlet as well as their relative deviation from the integrated particle source terms for flow past a sphere. For the laminar flow, the deviation from the integrated particle source terms ranges between 1.48×10 -8 % and 3.20×10 -3 %. The highest error can be found for the change in the species mass flow of C 4 H 10 between inlet and outlet, which can be attributed to a small inaccuracy in the overall mass balance as already reported by . In the turbulent case, the error in the heat and species mass balance is between 6.34 × 10 -5 % and 1.78 × 10 -2 %. The maximum deviation from the integrated particle source terms is located on the fluid side of the interface, due to the oscillating convergence behaviour of the kϵ turbulence model in the region of the highest wall share stress (20 • to 80 • from the forward stagnation point). This can be attributed to unsteady flow phenomena occurring in the investigated high subcritical particle Reynolds number range ). However, the small errors in the energy and material balance are in an acceptable range and demonstrate that the CHT and CMT model is able to couple correctly flow and reaction between a porous catalyst and the surrounding flow field. Besides checking overall energy and species mass conservation, the particle Nußelt number N u p and the particle Sherwood number of n-butane Sh p,C 4 H 10 is determined from the CFD simulation of flow around a spherical VPO catalyst particle and compared with literature correlations for different Re p numbers: