Numerical simulation of interactions between dissociating gases and catalytic materials in shock tubes

Shock tubes have become widely used to study thermodynamic processes in high temperature gas flows [1], [2] and chemical kinetics [3], [4]. Flow parameters behind incident and reflected shock waves were analyzed by Gaydon and Hurle [1], Bazhenova et al. [2], Sturtevant and Slachmuylders [5], Goldsworthy [6], Johannesen et al. [7], and Hanson et al. [8]. It was found that the gas behind the reflected shock wave is practically at rest in the laboratory coordinate system, and the temperature in this area is approximately twice as high as behind the incident shock wave. The purpose of the present study is to analyze heat transfer processes at the catalytic materials of the shock-tube end after shock wave refraction in terms of the model of the nonsteady-state nonequilibrium thermal boundary layer developed by Provotorov and Riabov [9], [10], [11]. The analysis [9] covered the time interval from 10 sec to 2.5 μsec, and it was restricted by the applied numerical method. In the present study we have developed the numerical algorithm and studied gasdynamic parameters and component concentrations in the layer for the time interval up to 100 μsec. The parameters behind the reflected shock wave [1], [2], [9], [11] were evaluated as the external boundary conditions for the layer. The nonequilibrium parameters in this area are the functions of initial parameters such as pressure and temperature in the shock-tube channel, velocity of the incident shock wave, etc. The dissociation, recombination and exchange reactions [4], [12] among the air components (O2, O, NO, N2, and N) were considered. At the shock-tube end a union boundary condition [5], [6], [7], [9] for temperature and heat flux was used, as well as a boundary condition for recombination of atomic components. Unfortunately, the identical experimental data are unknown to the author.