Numerical study of hydrogen mild combustion

Abstract

In this article a combustor burning hydrogen and air in mild regime is numerically studied by means of computational fluid dynamic simulations. All the numerical results show a good agreement with experimental data. It is seen that the flow configuration is characterized by strong exhaust gas recirculation with high air preheating temperature. As a consequence, the reaction zone is found to be characteristically broad and the temperature and concentrations fields are sufficiently homogeneous and uniform, leading to a strong abatement of nitric oxide emissions. It is also observed that the reduction of thermal gradients is achieved mainly through the extension of combustion in the whole volume of the combustion chamber, so that a flame front no longer exists ('flameless oxidation'). The effect of preheating, further dilution provided by inner recirculation and of radiation model for the present hydrogen/air mild burner are analyzed.

A review of MILD combustion and open furnace design consideration

“…Mollica et al, (2009) used CFD to study the effect of preheating, further dilution provided by inner recirculation and a radiation model for a hydrogen-air MILD burner. Noor et al, (2012aNoor et al, ( , 2012bNoor et al, ( , 2012cNoor et al, ( , 2012d used CFD to optimize the furnace parameters setup and air fuel ratio before the development of the furnace for experimental testing.…”

“…The configuration of reactants and exhaust ports was optimized using a CFD modeling study (Khoshhal et al, 2011;Noor et al, 2012aNoor et al, , 2012bSzegö et al, 2003). Mollica et al (2009) used CFD to study a hydrogen-air MILD burner. They reported on the effect of preheating, with further dilution being provided by an inner recirculation and radiation model.…”