Abstract

Numerical modeling of premixed combustion is important for a wide range of machines and systems focusing on compliance with the increasing pollutants reduction requirements. However good industrial numerical combustion models need a practical requiring, in this way, a balance between speed and accuracy. The flamelet models are suitable for this purpose providing a decoupling of the reactive and fluid dynamic problems, and an important model of this family is the b-Ξ flame surface wrinkling model. A specially challenging experiment to test this combustion model is the ORACLES test rig whose two independent parallel inlet channels consistently influence the turbulent combustion, injecting fuel and oxydizer at different equivalence ratios. The b-Ξ flamelet combustion model is known by the sensibility to numerical schemes and boundary conditions and, based on this, the present study proposes to investigate the coupling with the important SST k-ω turbulence model and achieve good balance among accuracy, boundedness, stability and efficiency using the ORACLES experiment.

Highlights

  • A truly instigating and challenging phenomenon of numerical modeling is the study of partially premixed turbulent combustion cases in closed environment

  • The wake is caused by the amplification of the pressure difference between the two inlets and the profile for Euler scheme shown in Fig. 5 does not represents the reality

  • It should be noted that backward scheme for temporal term has reached the best results and maintains plausible behavior whereas the Euler scheme amplifies the pressure oscilations and Besson (2001) Present work 1 234 5

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Summary

Introduction

A truly instigating and challenging phenomenon of numerical modeling is the study of partially premixed turbulent combustion cases in closed environment. There are several factors responsible for that, for example, a bigger coupling between chemistry and turbulence on premixed turbulent combustion in relation to the non-premixed problem (Bilger et al 2005). Specially gas turbines and internal combustion engines, the study of premixed turbulent combustion becomes a central point. In this combustion type the reactive wave propagates towards the reactant molecular mixture, initially in a deflagration speed (Lipatnikov 2012). An interesting feature of premixed flames is that its flammability and extinction limits depend on the flame front wrinkling, buoyancy (Qiao et al 2008), equivalence ratio, heat losses, among other factors

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