Effects of equivalence ratio and mixing pattern of reactants on flameless combustion

This paper reported the experimental results of flameless combustion obtained from investigation of the influence of equivalence ratio and initial reactants mixing pattern. The furnace operates at the thermal input of 7.5-15 kW, and equivalence ratio varying from 0.5 to 1. Experiments show that the flameless combustion is easy to maintain once it has been established. It is found that, regardless of using non-premixing, partially premixing or fully premixing pattern, the furnace temperature is similar while CO, H2 and NOx emissions are extremely low. When the equivalence ratio is near 1, although it is still in the flameless mode and NOx emissions are low, extremely high CO and H2 emissions are obtained and thus the combustion is not clean. When the equivalence ratio is less than 0.98, CO and H2 emissions are low in all the three cases, and relatively, the partially premixing produces the most of NOx whereas the fully premixing obtains the lowest. This paper also discussed the influence of equivalence ratio on NOx emissions in detail. © 2011 Chin. Soc. for Elec. Eng.