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Theoretical Guide

FLINT is a comprehensive framework for modeling chemically reacting flows with accurate thermodynamic, transport, and kinetic properties. This guide provides the theoretical foundation for FLINT's capabilities in multi-species gas dynamics and chemical kinetics.

Thermodynamic and Transport Properties

FLINT computes mixture properties from individual species data using established mixing rules. Key capabilities include:

Thermodynamic Properties

  • Mixture density, gas constant, heat capacities (\(c_p\), \(c_v\), \(\gamma\))
  • Enthalpy, internal energy, entropy (absolute and sensible)
  • Speed of sound
  • Partial derivatives with respect to pressure and enthalpy for real fluids

Transport Properties

  • Dynamic viscosity via Wilke's mixing rule
  • Thermal conductivity via Wilke's mixing rule
  • Species diffusion coefficients (optional)

For detailed formulations, see: Thermodynamic and Transport Properties

Chemical Kinetics

FLINT provides two approaches to modeling chemical composition:

Finite-Rate Kinetics

Compute mass source terms for each species, accounting for:

  • Elementary reactions: Arrhenius kinetics with modified temperature dependence
  • Three-body reactions: Collision partners with species-specific efficiencies
  • Pressure-dependent reactions: Lindemann and Troe falloff

For detailed formulations, see: Finite-Rate Kinetics

Chemical Equilibrium

Computes equilibrium compositions by thermodynamic optimization:

  • UV problems, constant internal energy and volume (or density)
  • NASA CEA methodology

For detailed formulations, see: Chemical Equilibrium