Realistic aviation fuel chemistry in computational fluid dynamics

The prediction of flame extinction, soot formation and heat transfer for kerosene (pool) fires is a key aspect for the characterisation of aviation fuels. In particular, one of the main numerical challenges is the description of complex interactions of chemical and physical phenomena. This work is devoted to the individuation of an optimised surrogate mixture for the development of a detailed chemical model describing liquid fuel pyrolysis, homogeneous combustion and the formation of soot precursors, as well as the implementation of the obtained kinetic mechanism in open source computational fluid dynamics (CFD). To this aim, the primary combustion products and corresponding rate determining step into the production paths are identified by means of sensitivity and reaction paths analyses under several initial conditions representative for the investigated scenarios. The results show that a binary mixture composed of 92%v n-decane and 8%v toluene reproduces the aviation fuel properties. Based on the numerical results obtained in this work for aviation fuel, it holds that the mass burning rate m''kgm-2s-1 dependence with pool diameter (Dp) expressed in meters is: m''=0.47∙1-exp-3.61∙Dp A reduced (detailed) kinetic mechanism consisting of 14 reactions is obtained and implemented in a CFD model. The numerical results are in accordance with experimental data retrieved from the literature. The observed data consistency validates the adopted procedure and allows for further considerations on soot precursor formation in case of diffusive flames of aviation fuel. © 2019 Elsevier Ltd