Flameless combustion is a clean combustion technology with low pollutant emissions.In order to explore the process of flameless combustion of different fuels under un-preheating conditions

by combining experimental method with numerical method

research on the realization conditions of flameless combustion of CH_4 and C_3H_8 without preheating is carried out.On this basis

the temperature field and pollutants changes of the two fuels when they reach flameless combustion are compared.The results show that

both fuels can achieve flameless combustion without preheating

when the fuel is CH_4

the working temperature in the furnace must be higher than 1 123 K

and when the fuel is C_3H_8

the working temperature in the furnace should be higher than 923 K.When the combustion state changes to a flameless combustion state

the temperature distribution in the furnace is even

and the average temperature of flameless combustion of CH_4 is 1 148 K

and that of C_3H_8 is 1 243 K.The CO and NO_x emission mass concentrations in the tail flue gas of CH_4 and C_3H_8 are both lower than 20 mg/m~3.Comparing the experimental results with the simulation results

it finds that the detailed chemical reaction mechanism numerical method-GRI-Mesh 3.0 can better simulate flameless combustion under non-preheating conditions.