Filtering Effect Of Thin Fiber Layer On Inhalable Particulate Matter

In recent years,the issue of air pollution has become a hot spot of worldwide concern.It is of great significance to study the filtration effect of different fiber filter layers on particulate matter and the transport characteristics of particulate matter inside the filter layer,so as to optimize the thin fiber layer structure for the protection of human physical and mental health.In this paper,the thin fiber layer prepared by electrospinning technology is taken as the research object.Through the combination of experiment and numerical simulation,the influence of different factors on the filtering effect of the filter layer is explored.The main content includes the following parts:Firstly,the formation of particulate pollutants and the filtration mechanism of nanometer thin layer are analyzed.Through literature investigation,the research achievements of nanometer-fiber filter materials in the field of air filtration in recent years are summarized,and it is found that electrospinning technology is an efficient technology to prepare nanometer fiber thin layer.Based on the electrospinning technology,a fiber filter layer with polyvinylpyrrolidone(PVP)was prepared.The influence of different factors on the fiber structure was observed through an electronic scanning lens.The results showed that the concentration of solution and the electrospinning voltage had significant effects on the fiber structure.Secondly,the experimental platform for filtration was designed.The particle flow with different particle size was generated by GRIMM7811 particle generator.The particle concentration,size distribution and pressure drop before and after the filter layer were detected and recorded by optical aerosol diameter spectrometer,and the factors influencing the filtration effect of fiber structure were studied.Then the experimental data were processed to quantify the purification performance of the nanofiber thin layer to particulate pollutants.It was found that the filter layer with electrospinning voltage of 12kV and solution concentration of 8%had the best filtration performance.Finally,the numerical simulation method was used to study the deposition process of particulate matter in the multi-layer composite fiber structure,and the filtration effect of the randomly distributed fiber structure on fine particulate matter was explored.The effects of different solid volume percentage,surface wind speed and fiber diameter on the purification efficiency were revealed.In general,the higher the solid volume percentage,the lower-the permeability of the particles,and the increase of the surface wind speed will reduce the difference caused by different solid volume percentage.In the face of particles with different particle sizes,the two fiber structures have good filtering effect at dp=50nm and 100nm,but the quality factor of the overall fiber structure is generally low.The research has important reference value for the optimal selection of filter element of air purifier in practical engineering.