Numerical simulation on combustion characteristics of biofuels with different calorific values

Combustion characteristics of the two-dimensional simplified combustor were simulated numerically for methane, marsh gas and biomass gas, with introduction of standard k-ε turbulence model, eddy-dispassion turbulence combustion model and P-1 radiation heat transfer model. The temperature distribution, NOx mass fraction distribution, flow field structure in the combustor were analyzed to obtain the combustion characteristics of fuels with different calorific values by comparing the combustion situations of different cross sections. Results show that, under the condition of same mass flow of inlet air and fuel, the combustion temperature decreases with the decline of calorific value of fuels, the temperature distribution is more uniform, the NOx emissions are diminished, and the flow velocity is reduced; the proper regulation of excess air coefficient can improve the effect of combustion burning, and the temperature distribution still meets the law that combustion temperature of fuels with high calorific value is higher than that of fuels with low calorific value; the mixing of combustible components with different calorific values in biofuels syngas will change the calorific value of syngas, and the appropriate mixing ratio can play a better role for biofuels.