The aerothermodynamics of thermochemical nonequilibrium carbon dioxide flows are studied. The chemical kinetics models of McKenzie and Park are implemented in a three-dimensional computational fluid dynamics code. The code incorporates a five-species gas model characterized by translational-rotational and vibrational temperatures. Solutions are obtained for flow over finite-length elliptical and circular cylinders for a freestream condition of u∞= 4.24 km/s, T∞= 1970 K, and hθ∞ = 9.0 MJ/kg. The computed flowfields are then employed to calculate Mach-Zehnder interferograms for comparison with experimental data. The accuracy of the chemical kinetics models is determined through this comparison. Also, the methodology of the three-dimensional thermochemical nonequilibrium code is verified by the reproduction of the experiments.