Assessment of Turbulence-Chemistry Interactions in Missile Exhaust Plume Signature Analysis

Study of Turbulence-Radiation Interaction in Hypersonic Turbulent Boundary Layers

“…It is well established today that in the field of combustion TCI significantly influences the turbulent mixing and the reaction of fuel and air at high speeds, and is important for predicting many flow quantities such as reaction rates and ignition delay. [1][2][3][4][5][6][7] The equivalent information is not yet known for hypersonic boundary layers. As a result, existing Reynolds-averaged-Navier-Stokes (RANS) calculations for hypersonic boundary layers have neglected the interrelationship between chemistry and turbulence, and the error introduced by such a simplification is largely uncertain.…”

Assessment of Turbulence-Chemistry Interaction in Hypersonic Turbulent Boundary Layers

“…= Reynolds number, u = w , dimensionless Re = Reynolds number, w u = w , dimensionless S ij = strain rate tensor, 1 2 @u i =@x j @u j =@x i , s 1 T = temperature, K T a = activation temperature T r = recovery temperature, T 1 0:9 1=2M 2 , K u = friction velocity, m=s W = molecular weight, kg=mol w = chemical production rate, kg=m 3 s Y = species mass fraction, dimensionless = specific heat ratio, C p =C v , dimensionless = boundary-layer thickness, mm = displacement thickness, mm = momentum thickness, mm = mixture thermal conductivity, J=K m s = mixture viscosity, kg=m s = stoichiometric coefficient, dimensionless = density, kg=m 3 ij = shear stress tensor, 2S ij and the difference is referred to as turbulence-chemistry interaction (TCI), where the overbar indicates a mean quantity. It is well established today that in the field of combustion TCI significantly influences the turbulent mixing and the reaction of fuel and air at high speeds and is important for predicting many flow quantities such as reaction rates and ignition delay [1][2][3][4][5][6][7]. The equivalent information is not yet known for hypersonic boundary layers.…”

Effective Approach for Estimating Turbulence-Chemistry Interaction in Hypersonic Turbulent Boundary Layers

“…Equations (3)(4)(5) show that w s T; c depends nonlinearly on its parameters (primarily temperature). As a result, w s T; c is usually different from w s T; c. The former can be referred as the "turbulent" reaction rate, in which turbulence fluctuations, including both temperature and species fluctuations, have been taken into account, and the latter can be referred as "laminar" reaction rate (although T and c i are mean turbulent profiles), which we would obtain if there were no turbulent fluctuations.…”

“…Most previous studies for TCI focused on mixing layers for combustion applications. In turbulent combustion, TCI significantly influences the extent of mixing between high-speed streams of fuel and oxidizer, as well as the reaction rates, and is important for predicting many phenomena such as flame stabilization and ignition time delay [1][2][3][4][5][6][7]. Significant efforts have been devoted to model the interrelationship between turbulence and chemistry, and several methods for the closure of the chemical source term have been proposed, one of which is the probability-density-function (PDF) method [6][7][8].…”