Cremer, MA
1997
A Model of Turbulent Mixing and Reaction for H2-Air Combustion
Cremer, M.A. and McMurtry, P.A.
Propulsion and Power, (in press), 1997. Funded by ACERC and National Science Foundation.
A one-dimensional stochastic turbulent mixing model is formulated for application to a constant diameter, cylindrical combustion geometry. Simulations are performed to study effects of turbulence and non-equilibrium chemistry on NO formation in a cylindrically confined H2-air jet. Effects of secondary air injectors, combustion tube diameter, flow rate, and equivalence ratio on NO formation are presented over a range of these parameters. It is illustrated that variations of these parameters can lead to reduced NO production by increasing the turbulence levels and through minimization of residence times in stoichiometric regions where NO production is greatest. Application of these results to the development of new burner concepts is addressed.
1994
Effects of Turbulence Length-Scale Distribution on Scalar Mixing in Homogeneous Turbulent Flow
Cremer, M.A.; McMurtry, P.A. and Kerstein, A.R.
Physics of Fluids, 6:2143, 1994. Funded by ACERC and US Department of Energy.
The linear eddy-mixing model is used to study effects of the turbulence length-scale distribution on the transient evolution of a passive scalar in a statistically steady homogeneous turbulent flow. Model simulations are carried out using both wide-band length-scale distributions reflecting high-Reynolds-number scaling, and narrow-band (in effect, low-Reynolds-number) distributions. The two cases are found to exhibit qualitative differences in mixing behavior. These differences are interpreted mechanistically. The narrow-band case yields the best agreement with published direct numerical simulation results, suggesting that those results are, in effect, low-Reynolds, number results not readily extrapolated to high-Reynolds-number mixing.
Cremer, MA
1997
A Model of Turbulent Mixing and Reaction for H2-Air Combustion
Cremer, M.A. and McMurtry, P.A.
Propulsion and Power, (in press), 1997. Funded by ACERC and National Science Foundation.
A one-dimensional stochastic turbulent mixing model is formulated for application to a constant diameter, cylindrical combustion geometry. Simulations are performed to study effects of turbulence and non-equilibrium chemistry on NO formation in a cylindrically confined H2-air jet. Effects of secondary air injectors, combustion tube diameter, flow rate, and equivalence ratio on NO formation are presented over a range of these parameters. It is illustrated that variations of these parameters can lead to reduced NO production by increasing the turbulence levels and through minimization of residence times in stoichiometric regions where NO production is greatest. Application of these results to the development of new burner concepts is addressed.
1994
Effects of Turbulence Length-Scale Distribution on Scalar Mixing in Homogeneous Turbulent Flow
Cremer, M.A.; McMurtry, P.A. and Kerstein, A.R.
Physics of Fluids, 6:2143, 1994. Funded by ACERC and US Department of Energy.
The linear eddy-mixing model is used to study effects of the turbulence length-scale distribution on the transient evolution of a passive scalar in a statistically steady homogeneous turbulent flow. Model simulations are carried out using both wide-band length-scale distributions reflecting high-Reynolds-number scaling, and narrow-band (in effect, low-Reynolds-number) distributions. The two cases are found to exhibit qualitative differences in mixing behavior. These differences are interpreted mechanistically. The narrow-band case yields the best agreement with published direct numerical simulation results, suggesting that those results are, in effect, low-Reynolds, number results not readily extrapolated to high-Reynolds-number mixing.