Aerothermodynamics of Launchers and Re-entry Vehicles

Module aims

This course explores the unique flow physics experienced by vehicles travelling at hypersonic speeds in an atmosphere. Compressible flow relations introduced in previous years are modified for hypersonic conditions and the role of viscosity is considered in the form of compressible boundary layers and shock/boundary-layer interactions. These building blocks are applied to predict the aero-thermodynamic performance of past and current spacecraft designed for atmospheric entry missions and evaluate new and emerging technologies that meet future mission requirements. The equations of motion to describe an entry mission and the entry environment itself are also defined.

- To familiarise students with the unique technical and environmental challenges of designing spacecraft capable of leaving and entering a planetary atmosphere;
- To equip students with the knowledge and tools to analyse and design such vehicles.

Learning outcomes

This course will equip students with the skills necessary to

  • Understand the extreme environments experienced by spacecraft during atmospheric entry and apply this knowledge to analyse the aero-thermodynamic performance of aerospace vehicles at hypersonic conditions, including the role of compressible boundary layers and shock/boundary-layer interactions.
  • Evaluate existing state-of-the-art designs and technologies for entry-descent-landing missions, based on an appreciation of the advantages and limitations of the various tools and methodologies available for doing so.
  • Evaluate the contrasting demands of re-entry missions on Earth and Mars, based on the parameters which affect the trajectories (spacecraft dynamics and atmospheric conditions).
  • Analyse the performance of current entry vehicles (including heat-shield technologies) and make appropriate design choices based on defined mission parameters.
  • Evaluate new and emerging technologies for future entry-descent-landing missions, including deployable ad inflatable aero-decelerators for high payloads missions to Mars. 

Module syllabus

- Motivation for access to space incl. historical context;
- Inviscid hypersonic aerodynamics: governing equations incl. definition of continuum and Knudsen number, hypersonic shock and expansion relations, hypersonic similarity parameter, Newtonian theory, with numerous analytical examples.
- Viscous hypersonic aerodynamics (compressible boundary layers): boundary layer equations, special case of thin b-l at high Re, heat transfer and Reynolds analogy, compressible boundary layer scaling, similarity solutions: van Driest, Reference temperature, stagnation point flow physics and heat transfer, viscous interaction, entropy layers, hypersonic boundary layer transition, high temperature gas dynamics incl. real gas effects and basic chemistry.
- Overview of atmospheric entry mission requirements and design philosophy, historical context, with special focus on the challenges of Entry, Descent, and Landing;

  •  E: Entry vehicle heat shield design: conventional and advanced concepts;
  •  D: Descent stage aerodynamic (parachute) and retropropulsive (thrusters) decelerators;
  •  L: Landing technologies: airbags, thrusters, legs, etc.; 

- Overview of the re-entry environment: atmospheric composition and characteristics – focus on Earth and Mars (plus Venus, Titan).
- Basic principles of 3DOF and 6DOF re-entry trajectory modelling, including ballistic coefficient, definition of coordinate systems, illustrative examples for lifting and non-lifting geometries, stability.
- Methods for estimating convective heating during re-entry:

  • Step-by-step boundary-layer-based method
  • Engineering correlations: Chapman, Sutton-Graves

- Case study: Mars EDL for future human missions;
- Shock-wave/boundary-layer interactions: basic physics, prediction of separation, SBLI types and classification, supercritical wings, transonic stall, buffet, SBLI unsteadiness, 3D effects in SBLIs, onset of Regular-Mach transition, flow control for SBLIs.

Pre-requisites

AERO50001 Aerodynamics 2;
AERO96001 Aircraft Aerodynamics
 

Teaching methods

Lectures and tutorials, with structured tutorial sheets and in-class progress tests

Assessments

Examined Assessment
2 hour written examination in January (100%)

 

Reading list