Numerical Simulation Collection Efficiency And Performance Of Fibrous Filfers

Pressure drop, capture efficiency are very important performance parameters of fibrous filter. Domestic and foreign scholars’studies on the performance of fiber filters have been for many years. There are several models in previous studies used to predict the Permeability of the filter, but the actual fiber filters structure was simplified, for example the fiber arrangement was simplified as inerratic, but the actual fiber filters structure was random permutation. If using these models to predict actual media, the results are disappointing. The Structure and operating parameters of fibrous filters play an important role for filter performance. So researching tructure and operating parameters of fibrous filters have important meaning for deep researching of Pressure drop,and capture efficiency. Fiber media of traditional fibrous filters foucs on in a single circular fiber. With the improvement of production technology development of the times, people can produce very complex shape profiled fiber to improve filtering performance,So this paper studies the collection efficiency on this issue profiled fiber.In order to get more realistic microstructure of fiber filter, in this paper, We write a program to generate random fibers based on the Visual Basic Applications, Through the secondary development of CAD generated models of random fiber filter. Using Lagrangian discrete phase model that DPM method for collection efficiency, pressure loss numerical simulation study The major studies and conclusions are as follows:(1) Established a variety of the filter model of structural parameters through VBA program Using Lagrangian discrete phase model that DPM method for many fibrous filters numerical simulation study, And gives the pressure loss correlations5-10, random fiber collection efficiency relational5-11,5-12,5-13.(2) Based on DPM method did the CFD simulation of a single fiber collection efficiency, The result indicates that the collection efficiency of the single fiber increased with the increase of solid volume fraction and the collection efficiency of the single fiber increased with the increase of solid stokes number,and giving relational3-3,3-19of collection efficiencyof the single fiber relational.(3) Based on DPM method did the CFD simulation of profiled fiber (round,square and oval fiber) collection efficiency. The result indicates that under the same conditions the largest collection efficiency is square fiber’s,round fiber’s followed and the worst is oval fiber’s. Under the same conditions the largest pressure drop is square fiber’s, round fiber’s followed and the worst is oval fiber’s. By analysis filter performance comprehensive indicators (quality factor Y) indidated square fibers’quality factor was maximum, i.e. the best filtering performance, circular, oval fiber closer.(4) It is obvious that Influence of structural parameters and operating parameters was to pressure loss and collection efficiency in fiber filter. The result indicates that With the increase of fiber diameter, fiber filter’s collection efficiency and pressure loss are reduced, With the increase of solid volume fraction, fiber filter collection efficiency and pressure loss are increased, With the increase of filtration velocity, fiber filter collection efficiency and pressure loss are increased, With the increase of particle diameter, fiber filter collection efficiency and pressure loss are increased.(5) The simulated data of Lagrangian discrete phase model that DPM and theoretical data is very closer. It indidates that the method of DPM can better reflect the impact of structural parameters and operating parameters on the collection efficiency of the filter fibers. Furthermore, the method of DPM can make the trajectory of particles clear and make the collecting behavior visualization,providing new ways to reasurch fiber collection efficiency for the future.