The turbulent combustion flow modeling is performed to study the effects of CO_2 addition to the fuel and oxidizer streams on the thermochemical characteristics of a swirl stabilized diffusion flame. A flamelet approa...The turbulent combustion flow modeling is performed to study the effects of CO_2 addition to the fuel and oxidizer streams on the thermochemical characteristics of a swirl stabilized diffusion flame. A flamelet approach along with three well-known turbulence models is utilized to model the turbulent combustion flow field. The k-ω shear stress transport(SST) model shows the best agreement with the experimental measurements compared with other models. Therefore, the k-ω SST model is used to study the effects of CO_2 dilution on the flame structure and strength, temperature distribution, and CO concentration. To determine the chemical effects of CO_2 dilution, a fictitious species is replaced with the regular CO_2 in both the fuel stream and the oxidizer stream. The results indicate that the flame temperature decreases when CO_2 is added to either the fuel or the oxidizer stream. The flame length reduction is observed at all levels of CO_2 dilution. The H radical concentration indicating the flame strength decreases, following by the thermochemical effects of CO_2 dilution processes. In comparison with the fictitious species dilution, the chemical effects of CO_2 addition enhance the CO mass fraction. The numerical simulations show that when the dilution level is higher, the rate of the flame length reduction is more significant at low swirl numbers.展开更多
In this paper,the unsteady magnetohydrodynamic(MHD)squeezing flow between two parallel disks(which is filled with nanofluid)is considered.The Galerkin optimal homotopy asymptotic method(GOHAM)is used to obtain the sol...In this paper,the unsteady magnetohydrodynamic(MHD)squeezing flow between two parallel disks(which is filled with nanofluid)is considered.The Galerkin optimal homotopy asymptotic method(GOHAM)is used to obtain the solution of the governing equations.The effects of Hartman number,nanoparticle volume fraction,Brownian motion parameter and suction/blowing parameter on nanofluid concentration,temperature and velocity profiles have been discussed.Furthermore,a comparison between obtained solutions and numerical ones have been provided.展开更多
文摘The turbulent combustion flow modeling is performed to study the effects of CO_2 addition to the fuel and oxidizer streams on the thermochemical characteristics of a swirl stabilized diffusion flame. A flamelet approach along with three well-known turbulence models is utilized to model the turbulent combustion flow field. The k-ω shear stress transport(SST) model shows the best agreement with the experimental measurements compared with other models. Therefore, the k-ω SST model is used to study the effects of CO_2 dilution on the flame structure and strength, temperature distribution, and CO concentration. To determine the chemical effects of CO_2 dilution, a fictitious species is replaced with the regular CO_2 in both the fuel stream and the oxidizer stream. The results indicate that the flame temperature decreases when CO_2 is added to either the fuel or the oxidizer stream. The flame length reduction is observed at all levels of CO_2 dilution. The H radical concentration indicating the flame strength decreases, following by the thermochemical effects of CO_2 dilution processes. In comparison with the fictitious species dilution, the chemical effects of CO_2 addition enhance the CO mass fraction. The numerical simulations show that when the dilution level is higher, the rate of the flame length reduction is more significant at low swirl numbers.
文摘In this paper,the unsteady magnetohydrodynamic(MHD)squeezing flow between two parallel disks(which is filled with nanofluid)is considered.The Galerkin optimal homotopy asymptotic method(GOHAM)is used to obtain the solution of the governing equations.The effects of Hartman number,nanoparticle volume fraction,Brownian motion parameter and suction/blowing parameter on nanofluid concentration,temperature and velocity profiles have been discussed.Furthermore,a comparison between obtained solutions and numerical ones have been provided.
