Research Abstracts Online
January 2010 - March 2011
University of Minnesota Twin Cities
College of Science and Engineering
of Aerospace Engineering and Mechanics
PI: Thomas E. Schwartzentruber
Molecular Simulation of Hypersonic Flows
This group’s research focuses on two related projects. The first involves molecular dynamics (MD) simulations of high temperature gas-surface interactions. When a spacecraft re-enters the Earth’s atmosphere, a strong shock wave dissociates air molecules into O and N atoms. These atoms recombine on the heat shield surface (catalytic recombination) and in doing so, deposit additional energy (heat) to the surface. Large uncertainties in recombination and heating rates lead to over-designed (heavier and more expensive) heat shields. This group is using a state-of-the-art reacting MD method (called ReaxFF) to analyze the dominant catalytic mechanisms and their rates for high temperature air interacting with both platinum and silicon-dioxide surfaces (a common element in heat shields).
The second project focuses on continued development of a highly scalable implementation of the direct simulation Monte Carlo (DSMC) particle method for gas dynamic simulations. The DSMC method simulates the Boltzmann equation and therefore is accurate for flow conditions ranging from continuum to free-molecular. The accuracy of this method is useful for high altitude applications, flows over micro-electromechanical systems (MEMS), and is useful for certain continuum flows for which complex molecular phenomenon become important (i.e. hypersonics). The mechanisms and rates computed from our gas-surface interaction project will be directly incorporated as boundary conditions for large DSMC simulations of flow over full hypersonic vehicles.
Bryon T. Edgar, Undergraduate Student
Da Gao, Research Associate
Paul E. Norman, Graduate Student
Cory Sorensen, Graduate Student
Paolo Valentini, Graduate Student
Chonglin Zhang, Graduate Student