Numerical Simulation Analysis Of Hydrogen/Oxygen Non-premixed Combustion In Symmetrical Four-lobe Nozzle

Nowadays,all kinds of equipment used in people’s daily life and in the industrial field are developing toward the scale reduction.One of the core parts of the most important power plant in the automotive and aerospace fields is the burner,which is also In order to enable the equipment to operate efficiently and stably,the combustion performance of micro-scale burners must be improved to meet the requirements.Therefore,exploring the characteristics of micro-scale combustion is of considerable value.Researchers around the world have also conducted a lot of explorations in this field.However,due to the particularity of micro-scale combustion,many problems have not been solved.This paper focuses on the research of the four symmetrical lobe burner,and explores the axial temperature change of the combustion chamber wall through the experimental method.Then,through numerical simulation,the combustion characteristics under different equivalence ratios and different fuel inlet flow rates were explored.It was found that the main reaction zone of combustion under various operating conditions was concentrated in the area near the exit of the lobe nozzle,and the OH group and high temperature zone were also mainly Distributed in this area.When the equivalence ratio increases,the high OH group concentration range decreases and the peak value of the OH group mass fraction gradually decreases and will shift slightly downwards,the flame height slightly increases,at the same axial height inside the nozzle H₂ The mass fraction is greater,and the H₂O mass fraction at the same position is smaller.The change of the equivalence ratio will also cause the distribution of the flow direction vortex array near the burner nozzle outlet,so that the degree of mixing of the reactants changes,the smaller the equivalence ratio,The better the blending effect.When the fuel inlet flow rate increases,the main reaction zone of combustion gradually extends away from the nozzle and extends downstream,and the combustion reaction in the combustion chamber is strengthened as a whole,the range of the OH group high concentration zone and the high temperature zone increases,and the axial distance of the maximum OH group increases,The flame height increases.The shape of the combustion chamber was adjusted on the basis of the existing cylindrical combustion chamber,and three new burners were obtained,namely:stepped combustion chamber,volcanic combustion chamber,and horn combustion chamber.After numerical simulation,it was found that the combustion characteristics of the three new burners under various operating conditions are roughly the same as those of the original burner,but through comparison with the original burner under various operating conditions,it was found at the low fuel inlet The combustion efficiency of the original burner is higher than that of the three new burners under the flow rate condition.When the fuel inlet flow rate is high,the combustion efficiency of the three new burners is higher than that of the original burner.And among the three new types of burners,the stepped type burner has higher combustion efficiency at high fuel inlet flow rate than the other two types of new type burners.