Progress in the Physical Chemistry of Hypersonic Flows: Quasiclassical Trajectory (QCT) Studies of Nitrogen Dissociation and Ro-vibrational Energy Transfer
Jason Bender, University of Minnesota
Understanding hypersonic reacting flows is crucial to the development of advanced aerospace technologies like new planetary re-entry systems and scramjet propulsion. The extreme temperatures and pressures in these flows present significant computational modeling challenges both for fluid mechanics and chemistry. We are pursuing a fundamental study of key gas-phase chemical reactions in air at hypersonic speeds. Central to this effort is a collaboration between experts in compressible gas dynamics and physical chemistry. Recent work by our groups focused on the construction of potential energy surfaces (PESs) to describe high-energy N2-N2 collisions, using advanced electronic structure methods and six-dimensional fitting techniques. We are using the new PESs to study the nitrogen dissociation reaction with unprecedented fidelity using the quasiclassical trajectory (QCT) method. Our research makes use of two tools: the Adiabatic and Nonadiabatic Trajectories (ANT) code from the Truhlar group; and a massively parallel trajectory code from the Schwartzentruber group. The approach, in which all quantum states of the reactants are modeled with minimal simplifications, enables us to accurately investigate nonequilibrium effects in the dissociation process. We are particularly interested in determining rates of energy transfer between rotational and vibrational modes in the reacting gas. Ultimately, we seek to incorporate our results into computational fluid dynamics simulations of hypersonic flows using codes from the Candler group.
Abstract Author(s): Jason D. Bender, Ioannis Nompelis, Zoltan Varga, Yuliya Paukku, Thomas Schwartzentruber, Donald G. Truhlar, Graham V. Candler