Experimental Study And Numerical Simulation Of Soot Suppression By Inserting Wire Mesh In Diffusion Flame

In recent years,our country’s comprehensive national power has become more powerful,the quality of life of the public has been greatly improved,motor vehicles have moved into thousands of households.The progress of automobile industry has not only promoted the rapid development of social economy,but also greatly improved the quality of living standard of our people and provided convenience for our daily travel.However,the development of automobiles towards industrialization has also caused great harmful effects on our environment and energy problems.Automobile exhaust contains carbon monoxide,nitric oxide,nitrogen oxides and various particles that can be inhaled by the human body,which are extremely harmful to human physical and mental health.With the year-by-year increase in vehicle ownership,the increasing efforts to reduce air pollution and proposed stricter emission standards for internal combustion engines,it has become imperative to design and manufacture cleaner and more efficient engines.There are three main approaches in the field of soot suppression: pulsating combustion,adding positive catalysts to the combustion process,and doping combustion.However,these methods still have defects such as high requirements for combustion environment,high requirements for operation accuracy,and the need to add additional complex systems.This paper is the first to propose the insertion of a wire mesh in a flame,which requires simple experimental equipment,no additional accessories,and is suitable for a wide range of fuel types without the need for additional mixing and blending steps.It is a simple and safe solution for a wide range of fuel flow rates,wire mesh numbers and nozzle diameters.A novel and efficiency strategy for suppression of soot from acetylene laminar diffusion flame is reported.In this work,a combination of experimental and numerical simulations is used to analyze that acetylene laminar diffusion flame.The soot generation is found to be greatly reduced through inserting wire mesh to the flame.The relationships between experimental parameters(i.e.,relative height of the wire mesh in the flame,the mesh number of the wire mesh and acetylene gas flow rate)and the suppression rate of soot are studied experimentally.The experimental results show that the soot generation tends to decrease first and then increase with the increase of relative height.In the case of larger relative height,the increase of mesh number makes the soot generation decrease first and then increase.And at the same relative height,the soot generation increases with the increase of acetylene flow rate.The numerical simulation results show that the experimental results have the same trend as the numerical simulation results.The insertion of wire mesh to the acetylene flame resulted in the reduction of soot precursor concentration,the reduction of soot particle concentration,and the reduction of soot mass,which led to the significant reduction of soot generation from acetylene laminar diffusion flame.The collected soot samples were characterized using transmission electron microscopy(TEM),high resolution transmission electron microscopy(HRTEM),X-ray diffraction(XRD),BET and Raman.The results show that the insertion of wire mesh to the flame can lead to a more irregular structure of the generated soot,which indicates an insufficient soot graphitization in nanostructure and subsequently results in a high amorphous feature and a low degree of structural ordered lead to an increase in soot oxidation reactivity,resulting in an increased oxidative reactivity of the soot.The insertion of wire mesh in the flame not only reduces the generation of soot,but also increases the oxidation of soot,thus achieving an effective suppression of soot generation from acetylene flames.