06/05/2011: The Role of Shock Layer Chemistry in Aerothermodynamic Heating

The Role of Shock Layer Chemistry in Aerothermodynamic Heating

May 6, 2011, 10:15 -11:00, CAB H52, ETH Zurich

Richard Jaffe

Aerodynamcis Branch, NASA Ames Research Center
When a space vehicle enters a planetary atmosphere it is subject to intense heating. A bow shock forms and results in intense heating of the gases in front of the spacecraft. The extent of dissociation and ionization of this gas effects the convective and radiative heat flux experienced by the vehicle. Under the aegis of the NASA Fundamental Aeronautics Program, the chemical and radiative phenomena for Earth and Mars entry are being studied. The goal of this task is to develop an accurate physics-based model for shock layer chemistry and radiation. I will present a brief overview of this effort and describe in detail our study of N2 thermal relaxation and dissociation.  This study consists of four parts: (1) generation of a quantum mechanical potential energy surface, (2) calculation of state-to-state collision cross sections and reaction rate coefficients for all 9390 rotation-vibration levels of N2, (3) solution of a 1-d Euler equations incorporating the full set of N2 levels, and (4) reduction of the dimensionality by using a coarse-grain energy-binning model.