Date of Award
Spring 5-2015
Access Type
Thesis - Open Access
Degree Name
Master of Science in Aerospace Engineering
Department
Aerospace Engineering
Committee Chair
Eric Perrell
First Committee Member
L.L. Narayanaswami
Second Committee Member
William Engblom
Abstract
A capability for higher accuracy heat transfer modeling in CFD for hypersonic re-entry flows, via inclusion of thermal radiation, is sought. With temperatures reaching tens of thousands of degrees, radiation is known to be significant to chemical reaction rates and thermal boundary layer development, hence surface heat transfer and thermal ablation both to the heat shield and the backshell region of re-entry vehicles. Two current NASA solicitations seek such an improved capability relative to the Mars and Earth entry problems, as uncertainty typically leads to overdesign and excess weight. The present research develops a first physics-based “building block,” which computes thermal radiation line strength distributions for certain species of interest. The spectral data required as inputs – electronic transition rates, energies, and wavelengths – for atomic nitrogen, oxygen, and hydrogen are obtained from a database maintained by NIST. Vibrational and rotational transitions of diatomic molecules are not addressed here. Absorption and emission coefficients are computed, hence an effective radiative thermal conductivity according to Rosseland is used in the “optically thick,” or “diffusion” approximation. Absorption and emission coefficients compared respectably with other published results, discrepancies attributable to differing sources of input spectral data. The computational module was implemented in an in-house Navier-Stokes research code, and demonstrated on a 2D hypersonic flow over a blunt body. The radiative diffusion model reduced peak temperatures and thermal gradients, as expected.
Scholarly Commons Citation
Scholz, Curtis, "Modeling and Simulation of Radiation from Electronic Transitions in Hypersonic Atmospheric Reentry Flow" (2015). Doctoral Dissertations and Master's Theses. 245.
https://commons.erau.edu/edt/245
