A cc ep te d M an us cr ip t 1 Fuel Pyrolysis through Porous Media : 1 Coke Formation and Coupled effect on Permeability 2

10 The development of hypersonic vehicles (up to Mach 10) leads to an important 11 heating of the whole structure. The fuel is thus used as a coolant. It presents an endothermic 12 decomposition with possible coke formation. Its additional permeation through the porous 13 structure involves internal convection. This implies very complex phenomena (heat and mass 14 transfers with chemistry). In this paper, the n-dodecane pyrolysis is studied through stainless 15 steel porous medium up to 820 K and 35 bar (supercritical state). The longitudinal profiles of 16 chemical compositions inside the porous medium are given thanks to a specific sampling 17 technique with off-line Gas Chromatograph and Mass Spectrometer analysis. By comparison 18 with previous experiments under plug flow reactor, the conversion of dodecane is higher for 19 the present experimental configuration. The pyrolysis produces preferentially light gaseous 20 species, which results in a higher gasification rate for a similar pyrolysis rate. The effects of 21 the residence time and of the contact surface area are demonstrated. The transient changes of 22 Darcy’s permeability are related to the coke formation thanks to previous experimental 23 relationship with methane production. A time shift is observed between coke chemistry and 24 ha l-0 07 05 54 9, v er si on 1 7 Ju n 20 12