Cited By (since 1996) 21International audienceHypersonic flight is expected to be achieved in the coming years by use of supersonic combustion ramjet. One of the main issues is the thermal management of the overall vehicle and more specifically the cooling of the engine. To simulate the behavior of an actively cooled supersonic combustion ramjet by use of supercritical endothermic fuel, a one-dimensional transient numerical model has been developed with heat and mass transfer, fluid mechanics and detailed pyrolysis chemistry. A supplementary step by step validation of the model is presented in this paper thanks to numerical and experimental comparison test cases. Fluid temperature profiles are in good agreement for steady-state calculations despite unconsidered 2-D effects due to momentum and thermal boundary layers. Heat fluxes conservation is verified. Thermal and hydraulic transient behavior are close to those of validation data. The present numerical modeling is quantitatively validated under steady state and transient conditions. Good agreement is found with experimental results on a chemical aspect. The model is suitable for conducting parametric studies on fuel pyrolysis in supercritical states and to use it for engineering applications as a predimensioning tool