Numerical modeling of several turbulent nonreacting and reacting spray jets is carried out using ... more Numerical modeling of several turbulent nonreacting and reacting spray jets is carried out using a fully stochastic separated flow (FSSF) approach. As is widely used, the carrier-phase is considered in an Eulerian framework, while the dispersed phase is tracked in a Lagrangian framework following the stochastic separated flow (SSF) model. Various interactions between the two phases are taken into account by means of two-way coupling. Spray evaporation is described using a thermal model with an infinite conductivity in the liquid phase. The gas-phase turbulence terms are closed using the k-e model. A novel mixture fraction based approach is used to stochastically model the fluctuating temperature and composition in the gas phase and these are then used to refine the estimates of the heat and mass transfer rates between the droplets and the surrounding gas-phase. In classical SSF (CSSF) methods, stochastic fluctuations of only the gas-phase velocity are modeled.
International Journal of Spray and Combustion Dynamics, 2009
Numerical simulations are performed on the flow of fine, polydisperse droplets of acetone ejected... more Numerical simulations are performed on the flow of fine, polydisperse droplets of acetone ejected from a round jet of air into an ambient turbulent, uniform co-flowing air stream. The objective is to validate the numerical model by comparing the predictions with experimental measurements of a well defined evaporating spray configuration (Chen et al., Int. J. Multiphase Flow 32(2006), 389-412). The carrier-phase is considered in the Eulerian context, while the dispersed phase is tracked in the Lagrangian framework. Various interactions between the two phases are taken into account by means of a two-way coupling. The stochastic separated flow (SSF) model is adopted for the spray calculations. The gas-phase turbulence terms are closed using the standard k-ε model. The spray evaporation is described using a thermal model with an infinite-conductivity.
International Journal of Numerical Methods for Heat & Fluid Flow, 2009
... K. Nagendra, National Institute of Technology Karnataka, Surathkal, India, and Department of ... more ... K. Nagendra, National Institute of Technology Karnataka, Surathkal, India, and Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India. KN Lakshmisha, Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India. ...
Lifted turbulent jet diffusion flame is simulated using Conditional Moment Closure (CMC). Specifi... more Lifted turbulent jet diffusion flame is simulated using Conditional Moment Closure (CMC). Specifically, the burner configuration of Cabra et al. , Proc. Combust. Inst. 29 (2002) 1881-1887] is chosen to investigate H 2 =N 2 jet flame supported by a vitiated coflow of products of lean H 2 /air combustion. A 2D, axisymmetric flow-model fully coupled with the scalar fields, is employed. A detailed chemical kinetic scheme is included, and first order CMC is applied. Simulations are carried out for different jet velocities and coflow temperatures (T c ). The predicted liftoff generally agrees with experimental data, as well as joint-PDF results. Profiles of mean scalar fluxes in the mixture fraction space, for T c ¼ 1025 and 1080 K reveal that (1) Inside the flame zone, the chemical term balances the molecular diffusion term, and hence the structure is of a diffusion flamelet for both cases.
Numerical modeling of several turbulent nonreacting and reacting spray jets is carried out using ... more Numerical modeling of several turbulent nonreacting and reacting spray jets is carried out using a fully stochastic separated flow (FSSF) approach. As is widely used, the carrier-phase is considered in an Eulerian framework, while the dispersed phase is tracked in a Lagrangian framework following the stochastic separated flow (SSF) model. Various interactions between the two phases are taken into account by means of two-way coupling. Spray evaporation is described using a thermal model with an infinite conductivity in the liquid phase. The gas-phase turbulence terms are closed using the k-e model. A novel mixture fraction based approach is used to stochastically model the fluctuating temperature and composition in the gas phase and these are then used to refine the estimates of the heat and mass transfer rates between the droplets and the surrounding gas-phase. In classical SSF (CSSF) methods, stochastic fluctuations of only the gas-phase velocity are modeled.
International Journal of Spray and Combustion Dynamics, 2009
Numerical simulations are performed on the flow of fine, polydisperse droplets of acetone ejected... more Numerical simulations are performed on the flow of fine, polydisperse droplets of acetone ejected from a round jet of air into an ambient turbulent, uniform co-flowing air stream. The objective is to validate the numerical model by comparing the predictions with experimental measurements of a well defined evaporating spray configuration (Chen et al., Int. J. Multiphase Flow 32(2006), 389-412). The carrier-phase is considered in the Eulerian context, while the dispersed phase is tracked in the Lagrangian framework. Various interactions between the two phases are taken into account by means of a two-way coupling. The stochastic separated flow (SSF) model is adopted for the spray calculations. The gas-phase turbulence terms are closed using the standard k-ε model. The spray evaporation is described using a thermal model with an infinite-conductivity.
International Journal of Numerical Methods for Heat & Fluid Flow, 2009
... K. Nagendra, National Institute of Technology Karnataka, Surathkal, India, and Department of ... more ... K. Nagendra, National Institute of Technology Karnataka, Surathkal, India, and Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India. KN Lakshmisha, Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India. ...
Lifted turbulent jet diffusion flame is simulated using Conditional Moment Closure (CMC). Specifi... more Lifted turbulent jet diffusion flame is simulated using Conditional Moment Closure (CMC). Specifically, the burner configuration of Cabra et al. , Proc. Combust. Inst. 29 (2002) 1881-1887] is chosen to investigate H 2 =N 2 jet flame supported by a vitiated coflow of products of lean H 2 /air combustion. A 2D, axisymmetric flow-model fully coupled with the scalar fields, is employed. A detailed chemical kinetic scheme is included, and first order CMC is applied. Simulations are carried out for different jet velocities and coflow temperatures (T c ). The predicted liftoff generally agrees with experimental data, as well as joint-PDF results. Profiles of mean scalar fluxes in the mixture fraction space, for T c ¼ 1025 and 1080 K reveal that (1) Inside the flame zone, the chemical term balances the molecular diffusion term, and hence the structure is of a diffusion flamelet for both cases.
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