This is an attempt to develop Equation of State models of high-temperature dissociating air using the Ideal Dissociating Gas model (Lighthill, 1957). Although this is not a rigorous implementation of dissociating air (with numerous little species like ionic radicals and so) there is a significant match between NASA CEA and the current model for most cases, making it fairly robust. Numerical algorithms used in this code can be found in "Physical Gas Dynamics", by Vincenti and Kruger. This code is written in a user-friendly easy-to-understand manner, with as close resemblance to equations on a paper. This hence makes it a great starting point for those with the aim to understand/develop their custom equation of state solvers for dissociating air for reacting gas dynamics applications. The developed solver's capabilities are illustrated with the help of some benchmark test cases, expounded further below.
One can generate normal shock tables using this solver for hypersonic speeds (>mach 5.0). It is widely known that a significant deviation is spotted from the non-reacting/non-dissociating gas-dynamics assumption for traditional compressible flow tables for mach-numbers nearing mach 5.0 and above. Results of this solver have been benchmarked with NASA CEA's "shock-tube" case for temperature, pressure, density and enthalpy ratios. The trend between mach-number and the said ratios have been compared to plots available in "Hypersonic and High-Temperature Gas-Dynamics", Anderson.J.D, 2006 (2nd edition).
Expanding flow around a convex corner at hypersonic speeds and high-termperatures is explored and Prandtl-Meyer angles for the same have been evaluated. This is obtained by seeking solutions numerically to the governing ODE for PM-angles and the equation of state. Trends are matched with plots in Vincenti and Kruger and there is a significant match. TODO-pics and charts
Dissociating air flow through a de-Laval nozzle is implemented using this solver and the results are compared using the "rocket" problem of NASA CEA.