Turbulent nonpremixed effects

Barlow, R. S., R. W. Dibble, J.-Y. Chen, and R. P. Lucht (1990). Effect of Damkohler number on superequilibrium OH concentration in turbulent nonpremixed jet flames. Combustion and Flame 82, 235-251. 

Chen, J. Y. and W. Kollmann (1988). PDF modeling of chemical nonequilibrium effects in turbulent nonpremixed hydrocarbon flames. In Twenty-second Symposium (International) on Combustion, pp. 645-653. Pittsburgh, PA The Combustion Institute. 

Pdf modeling of finite-rate chemistry effects in turbulent nonpremixed jet flames. 

Wang, C., and Barlow, R. S. "Spatial Resolution Effects on the Measurement of Scalar Variance and Scalar Gradient in Turbulent Nonpremixed Jet Flames." Experiments in Fluids 44 (2008) 633-45. 

Kronenburg, A. and R. W. Bilger (1997). Modeling of differential diffusion effects in nonpremixed nonreacting turbulent flow. Physics of Fluids 9, 1435-1447. 

Of major interest concerning these problems are influences of turbulence in spray combustion [5]. The turbulent flows that are present in the vast majority of applications cause a number of types of complexities that we are ill-equipped to handle for two-phase systems (as we saw in Section 10.2.1). For nonpremixed combustion in two-phase systems that can reasonably be treated as a single fluid through the introduction of approximations of full dynamic (no-slip), chemical and interphase equilibria, termed a locally homogeneous flow model by Faeth [5], the methods of Section 10.2 can be introduced reasonably successfully [5], but for most sprays these approximations are poor. Because of the absence of suitable theoretical methods that are well founded, we shall not discuss the effects of turbulence in spray combustion here. Instead, attention will be restricted to formulations of conservation equations and to laminar examples. If desired, the conservation equations to be developed can be considered to describe the underlying dynamics on which turbulence theories may be erected—a highly ambitious task. 

To represent the partially premixed turbulent combustion of a refinery gas in the heater, a combination of the flamelet formulations for premixed and nonpremixed combustion was used [16]. The standard k-e model was used for turbulent flow calculations. The effect of turbulence on the mixture fraction was accounted for by integrating a beta-PDF derived from the local mixture fraction and mixture fraction variance, which were in turn obtained by solving their respective transport equations. A relatively simple approach was used to compute radiant heat transfer—a diffusion model with a constant absorption coefficient (0.1 m i). 

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