Study On Combustion Characteristics Of Aluminum Powder Laminar Flame

In the combustion process,metal powder fuel has both the advantages of liquid fuel and solid fuel combustion,and the theoretical combustion performance is superior.However,due to the complexity of the gas,solid and liquid multiphase combustion flow formed by the powder fuel in the combustion chamber,the combustion mechanism of the powder fuel is still controversial.Based on the above reasons,it is necessary to study the combustion mechanism of metal powder fuel and improve the combustion performance of powder fuel.Although there are many fuels available for metal powder engines at this stage,aluminum is an ideal fuel for powder engines because of its abundant reserves and low production costs.Therefore,this subject takes aluminum particles as the research object to analyze the combustion characteristics of aluminum particles under laminar combustion conditions.Taking the existing burner model as a reference,an experimental platform is designed and built,which mainly includes the burner,gas supply system,acquisition system,ignition system and exhaust system.The burner consists of a powder supply device,a fluidization device and a combustion device.The experimental study shows that the burner can produce a relatively uniform and stable gas-solid two-phase flow,which meets the design requirements.Based on Fluent software,the aluminum powder/nitrogen non-premixed laminar flame was numerically simulated,and the flame temperature,intermediate products,combustion products,and the evaporation process and trajectory of aluminum particles were analyzed.The temperature from the inside to the outside gradually increased,the intermediate components mainly existed in the reaction zone,and the Al O radiation could well represent the flame shape.The evaporation process of aluminum particles was almost synchronized with the combustion process.With the increase of gas-solid two-phase flow velocity and annular inlet velocity,the low temperature range gradually increased,and the "single flame peak" phenomenon of aluminum particles in the combustion process was found.Based on the built experimental system,the flame characteristics of Al/air premixed laminar combustion were studied.The ignition process,flame shape and distribution of intermediate products(especially Al O)of aluminum powder laminar flames with different gassolid two-phase flow velocities and different equivalence ratios were studied respectively.The combustion process is simulated by numerical simulation,and the flame shape of the aluminum particle group,the temperature of the flow field,the distribution of components in space and the evaporation process of the aluminum particle group are obtained.The flame shape is consistent with the experimental results,but the flame temperature is lower than the theoretically calculated temperature.