Numerical Analysis Of Flow Field And Combustion Characteristics Of Gas Burner For Asphalt Mixing Equipment

The heat released by the fuel combustion in the asphalt mixing equipment evaporates the water in the cold aggregate and heats it to the rated temperature.Its thermal performance plays a crucial role in the safe operation and economic benefits of the asphalt mixing equipment.However,the nitrogen oxides(NO_x)produced by fuel combustion seriously polluted the atmosphere.It is of great value and significance to study the influence of different combustors on the flow field and characteristics of NO_x emission.In this paper,the flame length,heat exchange efficiency and NO_x emissions are used as evaluation indexes,and the influence of the swirl structure in the burner on the performance of the burner is studied by numerical simulation.Based on this,the design and optimization of the new burner are carried out.The main contents of this paper are as follows:Firstly,the geometric modeling and numerical analysis of a gas burner with single swirler are carried out,and the reliability and correctness of the numerical model are verified by comparing the results of combustion experiment and numerical simulation of the burner.Based on this numerical model,the vane angle and number of parametric studies are performed on the swirler,and its influence on the flow field and combustion characteristics of the burner is explored.Secondly,a swirler with two-stage vanes was designed on the basis of a swirler with single-stage vane,it was found that the flame length of the burner with two-stage vanes was improved by comparing the two.Then,the structure with central nozzle was introduced based on the swirler with two-stage vanes by using the fuel fractional combustion technology,and the influence of fractional combustion on NO_x emissions is explored.On this basis,the angle of the secondary vane is parameterized and matching law between the primary and secondary vane is analyzed,and the optimal structural design scheme of heat exchange efficiency and flame length is sought.Finally,a new type of structure with conical body is proposed based on the principle of flame stabilization,which is introduced into the swirler with two-stage vanes,and the parametric discussion was carried out on the half-cone angle of conical body,and the law of different half-cone angles on the flame stability,flame length and heat exchange efficiency of the burner was analyzed,and the design scheme of the swirler was optimized.