Mechanism Analysis of Turbulent Heat Transfer in Porous Coking of Hydrocarbon Fuels under Supercritical Pressure

The effect of carbon deposits based on the porous properties in aero-engine cooling channels on turbulent heat transfer is numerically studied. As such, a CFD coupling model combining fuel pyrolysis and porous media model is established. The comparison results between the porous and solid coking that porous coking has a higher heat transfer efficiency than solid coking. At delta(c) = 60 mu m, the total heat transfer coefficient (THTC) of porous coking is 98 W m(-2) K-1 higher than that of solid coking. Considering the effect of porosity on porous coking, it could be seen that the THTC of porous coking first increases and then decreases with the increase of porosity. The critical porosity finds around 39.0%. Finally, the influence of spatial inhomogeneity of coking morphology is studied. It was indicated that the THTC for porous coking with inhomogeneous porosity is higher than the arithmetic mean of the homogeneous porosity. Inhomogeneity porosity porous coking with 6 and 72% porosity is 39 W m(-2) K-1 higher than the arithmetic mean of homogeneous porosity.