AHM

AHM is an Aerothermal Heating Module which interfaces to a trajectory simulation to provide the heat transfer, temperature and ablation history of an object undergoing entry into a planetary atmosphere. This module represents the first application of re-entry vehicle design community knowledge to a destructive spacecraft re-entry tool. As such, it benefits from significant improvements to the representation of ablation of composite materials, which can be performed using either a Heat Balance Integral (HBI) model, or the one-dimensional CAM ablation module:

  • Aerothermal Heat Transfer Models - AHM contains a selection of aerothermal heating correlations for convective and radiative re-entry heating, with appropriate default parameters, for a number of geometric primitives. Further improvements to representation of heating, based on higher fidelity methods, are in development with our international partners, under contract to the European Space Agency.
  • Heating Models - AHM contains a bulk heating model for metallic objects, with an HBI or 1D model for insulators and ablators. It includes the effects of radiative cooling and hot wall enthalpy correction during the heating phase, and convective cooling in the post-heating phase of the entry.
  • Demise Models - AHM is supplied with a selection of demise models, including the appropriate phenomenologies for melting and ablating materials. These can be applied in both 0D and 1D.
  • Materials Library - AHM has an extensible material and gas library. As standard this contains entries for a number of common spacecraft materials. This state-of-the-art library has been updated with the latest results from an ESA study into the demisability of spacecraft materials. Additional bespoke materials can be added at run time.
  • Modular - The architecture of AHM permits the most appropriate components including the material response to be chosen from libraries at execution time.
  • Extensible - Interface definitions are provided for all key components permitting clients to construct particular heating models optimised for their specific material behaviour, including ablators and meteorites.
  • Configurable - All aspects of AHM can be configured using JavaScript. This enables sequences and complex conditional scenarios to be scripted and evaluated without resorting to changes in the core engineering simulation.
  • High performance - Simulation scripts can be constructed which execute multiple ATS3 / ATS6 / AHM simulations in parallel, allowing modern multi-core / multi-processor hardware to be fully exploited. ATS3 with AHM embedded has been benchmarked at 1.1 million simulation steps / second on a standard Intel Core i7 processor.
  • Portable - Written in a combination of Java and JavaScript, AHM is fully supported on Windows, Unix / Linux and OS X.