An investigation on the effect of chemical kinetics in the modeling of combustive gaseous oxidizer flow on a solid fuel surface

In this study, the combustion process of gaseous Oxygen on the surface of HTPB (Hydroxyl-Terminated Polybutadiene) solid fuel has been investigated. To simulate the chemically reactive flow, Navier-Stokes equations and species transport equations were solved using LU-SW implicit scheme. Modeling this kind of combustion process demands a deep understanding of the pyrolysis phenomenon on the solid fuel surface. Experimental studies conducted in this field show that the main gaseous product of the pyrolysis process is C₄H₆. An experimental equation which is dependent to the temperature of the fuel surface is used to determine the gas production rate during pyrolysis process. The temperature of the fuel surface can be obtained by applying energy equation in gas-solid interface. The combustion process of gaseous Oxygen and C₄H₆ has been described by two quasi-global chemical kinetics models. According to the obtained results, the main characteristic parameters of combustive flow such as the flame temperature and mass fraction of chemical species are strongly affiliated to the applied chemical kinetics model. Finally, the results of modeling based on two different models of chemical kinetics are presented and solid fuel surface regression rate is compared with other numerical results.