PhD Public Defense of James Scoggins

Date: Friday 29 September 2017 to Friday 29 September 2017

Location : CentraleSupélec in Paris, Amphi IV, Bâtiment Eiffel 8-10 rue Joliot-Curie 91, 190 Gif-sur-Yvette France
Contact : Phone: +32 2 359 96 11


The thesis is entitled:

Development of numerical methods and study of coupled flow, radiation, and ablation phenomena for atmospheric entry


This thesis focuses on the coupling between flow, ablation, and radiation phenomena encountered in the stagnation region of atmospheric entry vehicles with carbon-phenolic thermal protection systems (TPS). The research is divided into three parts: 1) development of numerical methods and tools for the simulation of hypersonic, non-equilibrium flows over blunt bodies, 2) implementation of a new radiation transport model for calculating non-equilibrium radiative heat transfer in atmospheric entry flows, including ablation contaminated boundary layers, and 3) application of these tools to study real flight conditions.

A review of the thermochemical non-equilibrium models and governing equations for atmospheric entry flows is made, leading to a generalized framework, able to encompass most popular models in use today. From this, a new software library called MUlticomponent Thermodynamic And Transport properties for IONized gases, written in C++ (MUTATION++) is developed, providing thermodynamic, transport, chemistry, and energy transfer models, data, and algorithms, relevant to non-equilibrium flows. In addition, the library implements a novel method, developed in this work, for the robust calculation of linearly constrained, multiphase equilibria, which is guaranteed to converge for all well posed constraints, a crucial component of many TPS response codes.

The steady-state flow along the stagnation line of an atmospheric entry vehicle is computed using a one-dimensional, finite-volume tool, based on the dimensionally reduced Navier-Stokes equations. Coupling with ablation is achieved through a steady-state ablation boundary condition using finite-rate heterogeneous reactions at the surface and imposed equilibrium compositions of pyrolysis outgassing.

The High Temperature Gas Radiation (HTGR) database provides accurate line-by-line (LBL) spectral coefficients. From a review of the major mechanisms contributing to the radiative heat flux for atmospheric entry vehicles, several contributions are added to the HTGR database, including H lines, C3 Swings and UV electronic systems, and photoionization of H, H2, and CH. The Hybrid Statistical Narrow Band (HSNB) model is implemented to reduce the CPU time required to compute accurate radiative heating calculations when many species are present. New SNB parameters are computed for the H2 Lyman and Werner systems, by adjusting the Doppler and Lorentz overlap parameters to fit curves of growth for each narrow band. Comparisons with band-averaged LBL transmissivities show excellent agreement with the SNB parameters. It’s shown that the HSNB method provides a speedup of two orders of magnitude and can accurately predict wall radiative fluxes to within 5 % of LBL results. A novel spectral grid adaptation is developed for atomic lines and is shown to provide nearly identical results compared to the high-resolution HSNB method with a 20-fold decrease in CPU time. The HSNB model yields greater accuracy compared to the Smeared-Rotational-Band model in the case of Titan entry, dominated by optically thick CN radiation.


Upcoming Lecture Series / Events

Sep 10th - Sep 14th, 2018
Introduction to optimization and multidisciplinary design
VKI Lecture Series
Sep 17th - Sep 20th, 2018
Pyrolysis phenomena in porous media
VKI Lecture Series
Oct 8th - Oct 12th, 2018
Introduction to Measurement Techniques
VKI Lecture Series
Oct 15th - Oct 19th, 2018
Uncertainty Quantification in Computational Fluid Dynamics (STO-AVT 326)
VKI Lecture Series
Nov 5th - Nov 7th, 2018
Introduction to Ground Testing Facilities
VKI Lecture Series
Nov 26th - Nov 29th, 2018
Flow Characterization and Modeling of Hypersonic Wind Tunnels (STO-AVT 325)
VKI Lecture Series
Dec 5th - Dec 7th, 2018
10th European CubeSat Symposium
Other event
Jan 21st - Jan 25th, 2019
Introduction to Computational Fluid Dynamics
VKI Lecture Series
Feb 5th - Feb 7th, 2019
MYRTE Final International Workshop – MYRRHA Research and Transmutation Endeavour
Feb 18th - Feb 22nd, 2019
Radial Compressor Design and Optimization
VKI Lecture Series
Feb 25th - Mar 1st, 2019
Aircraft Passive and Active Noise Control
VKI Lecture Series
Mar 11th - Mar 13th, 2019
Symposium of VKI PhD Research 2019 - FREE REGISTRATION
VKI conferences
Mar 25th - Mar 26th, 2019
Introductory course to OpenFOAM®
Other event
Mar 27th - Mar 27th, 2019
OpenFOAM® general programming
Other event
Mar 28th - Mar 28th, 2019
4th Workshop of Belgian OpenFOAM®
Apr 8th - Apr 12th, 2019
Aicraft Electric Propulsion
VKI Lecture Series
May 6th - May 10th, 2019
CFD for Atmospheric Flows and Wind Engineering
VKI Lecture Series
May 20th - May 24th, 2019
Turbulent Combustion
VKI Lecture Series
Twitter Facebook Twitter Subscribe




ESA          LEDITH