Laminar Parallel Stream Mixing with Dissociation and Recombination

The boundary layer approximation is used to obtain closed-form solutions for the approach to equilibrium in a constant velocity mixing zone, i.e., the velocity gradients are neglected and only temperature and concentration gradients are considered. The chemical system consists of symmetric diatomic molecules and their atoms. A rate of atom production is assumed that is proportional to the difference between local atom concentration and the atom concentration associated with equilibrium mixing. The limiting cases of frozen flow and equilibrium flow appear as special cases of the general solution. Initial composition before mixing and composition outside the mixing zone need not be in local chemical equilibrium. It is shown that nonequilibrium conditions outside the mixing zone can have a strong influence on the evolution toward equilibrium within the mixing zone.