Investigation of Post-flame Heterogeneous Catalysis Using Laser Diagnostics and Numerical Modeling- Studies on a H_2/O_2/Pt System

摘要

A novel method for studying heterogeneous catalysis in a post-flame gas environment is presented. It involves saturated laser induced Fluorescence measurements made at two locations close to the substrate in a one dimensional steady state stagnation-point flow. The system is modeled using a numerical code that accounts for finite-rate gas-phase and surface chemical kinetics and multicomponent molecular transport. The two point measurements yield a parameter which can be unambiguously used for model validation at various operating conditions. Further, the measurements in conjunction with the model are used to obtain the destruction rate of a species (OH in the present case) in the gas-phase close to the substrate (J); this is shown to be directly correlated to the destruction rate at the surface. The obtained destruction rates at different operating conditions are compared quantitatively and qualitatively to those obtained from the model. Finally, the ratio of J to the gas-phase OH number density, under different operating conditions, is shown to follow the trends of the bare site fraction of the platinum surface.