Research On Resuspension Property Of Fiber Particles Under Air Jet

In the production process of the textile industry,a large amount of fiber particles will be generated,which will deposite on the surface of the equipments after being dispersed into the air,causing adverse effects on these equipments.When the touring and suction device of the textile equipment is reciprocating,or the workshop personnel use compressed air for daily equipment cleaning,or other airflows occer,the fiber particles depositing on the surface of the equipment will suspend again,causing the deposited fiber particles to be dispersed again.Once resuspending in the air,it will adversely affect the operating environment,production equipment,product quality,and even personnel health.Therefore,in order to more efficiently clean the deposited fiber particles as well as controlling the large-scale diffusion of resuspended particles,and to improve the indoor environmental quality of the cotton spinning workshop,it is necessary to conduct in-depth research on the resuspending characteristics of fiber particles under the action of airflow.In response to this problem,this article completed the following work:First,through on-site field investigation and sampling,with the help of microscopes and other basic methods,the shape and size characteristics of the fiber particles suspended in the cotton spinning workshop were analyzed,and the boundary conditions of the particles studied in this topic were established.Using this as a reference,the force analysis of the particles during the resuspension process was carried out,and the quantitative evaluation index of the particle resuspension characteristics was determined.Secondly,an experimental research platform was built for resuspension of fiber particles,using cotton powder particles as the research object,and studies the physical process of particles resuspension from the deposition surface after being impacted by the jet.By designing orthogonal experiments,the effects of jet velocity,jet height,surface area dust amount,jet incident angle and surface roughness of deposited particle carrier on particle resuspension characteristics were studied and analyzed.Thirdly,the significant influencing factors were studied to qualitatively and quantitatively analyze the diffusion process,resuspension rate and resuspension intensity of the particle cloud during resuspension.The main conclusions of the study are as follows:(1)The average length and diameter of suspended dimensional particles in the cotton spinning workshop were analyzed using a microscope to be 417.25μm and 13.78μm,respectively,which established the particle geometric size boundary for the experimental research object.After testing and analysis,the average length and diameter of the cotton powder particles used in the experiment were 468.44 μm and 20.46 μm respectively,which was equivalent to the geometrical size of suspended particles in the cotton spinning workshop.At the same time,by analyzing the mechanical equations of non-spherical particulate matter resuspension under the action of airflow,many factors affecting the particle resuspension process were obtained.(2)Through orthogonal experiment design and result analysis,it is found that combining the two indicators of resuspension rate and resuspension strength,the roughness of the particle carrier of the sedimentary plate is the main and highly significant influencing factor of particle resuspension strength,the jet velocity and the angle of incidence are significant influencing factors,while the surface area dust amount and jet height have no significant effect on the resuspension process.(3)Observing the dynamic process of resuspension of fiber particles,it is found that the particle trajectory is similar to the structure of the impinging jet flow field.At this time,the motion of the resuspended particles mainly depends on the wall jet,and the particle resuspension is consistent with the wall shear force curve of the impinging jet.(4)The results of univariate control experiments with significant influencing factors show that the resuspension ability of particles shows an increasing trend and then decrease with roughness.In turn,the adhesion between the surface and the particles reduced;when the roughness increased to a certain degree,the pits of the surface material are larger,which will hinder the resuspension of some particles.(5)The deposited particles are easier to resuspend under the impact of the vertical jet,and the resuspension rate and resuspension intensity gradually increase with the increase of the incident angle,when the incident angle of the jet is greater than 60 °(based on the experimental parameter settings in this paper),increasing the angle of incidence reduces the promotion effect of the fiber particle resuspension process.