Title: Simulation of a MILD combustion burner using ILDM chemistry

Authors: Artan Hoxha; İ. Bedii Özdemir

Addresses: Department of Energy, Polytechnic University of Tirana, Sheshi Nënë Tereza, Nr. 4, Tiranë, Albania ' Faculty of Mechanical Engineering, Istanbul Technical University, Gumussuyu 34437, İstanbul, Turkey

Abstract: A numerical study was performed to accommodate mathematical simplification of kinetics and non-premixed reactants in three-dimensional computations. Specifically, the ILDM technique was combined with the presumed probability density function approach to simulate turbulent combustion in a burner operating at MILD combustion, which was characterised by relatively uniform temperatures with no visible flame and sound. An Eulerian solution strategy was implemented in a CFD code on a structured mesh. Predictions of the mean flow field, turbulence kinetic energy, mixture fraction and its variance, temperature, and mass fraction of CO₂ and H₂O were presented. It is found that the flow near the burner exhibited strong anisotropy and, thus, k-ε turbulence model has over predicted the spread of the jets. Nevertheless, the calculated mean velocities and temperatures reproduce experimental data reasonably well. The mixing mechanism in the near field of the burner was fully described with remarks on the entrainment of flue gas. Low levels of turbulence in the lifted reaction zone were particularly emphasised with relevance to the homogeneity of the temperature field.

Keywords: MILD combustion; moderate or intense low oxygen dilution; simulation; ILDM chemistry; intrinsic low dimensional manifolds; computational fluid dynamics; CFD; non-premixed combustion; kinetics; non-premixed reactants; turbulence modelling.

DOI: 10.1504/PCFD.2014.063861

Progress in Computational Fluid Dynamics, An International Journal, 2014 Vol.14 No.4, pp.233 - 243

Published online: 16 Aug 2014 *

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