Modeling and measurements of a 16-kW turbulent nonadiabatic syngas diffusion flame in a cooled cylindrical combustion chamber

A model is presented to predict nonadiabatic combustion of syngas under gas turbine conditions. Mixing, combustion, and heat loss are described with f our independent scalar variables. These are the mixture fraction, an enthal py variable and two reaction progress variables for combustion of hydrogen and carbon monoxide. In the combustion model, turbulence is taken into acco unt by weighting with an assumed shape probability density function. The mo del is used to calculate a 16-kW flame in an air cooled combustion chamber. The fuel consists of 40% CO, 40% H-2, and 20% N-2 resulting in a calorific value of 11.9 MJ/kg. The calculated CO, CO2, O-2, and NO concentrations ar e compared with suction probe measurements at several locations in the comb ustion chamber. The nonadiabatic calculations and the measurements show goo d agreement. Adiabatic calculations show a significant overprediction of NO . It is concluded that the nonadiabatic model is necessary and suitable to calculate NO formation in dames with heat loss. (C) 2001 by The Combustion Institute.