Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the ...Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the reservoir pressure, and the filtration velocity on the cleaning effectiveness are analyzed. Experimental results show that there exists an optimum dust cake thickness for pulse-cleaning process. For thin dust cake, the patchy cleaning exists and the cleaning efficiency is low; if the dust cake is too thick, the pressure drop across the dust cake becomes higher and a higher reservoir pressure may be needed. At the same time there also exists an optimum reservoir pressure for a given filtration condition.展开更多
Alumina （MMAD： 32.45μm） was used to study dust cake formation in fiber filter at steady-state operation. Cake vertical profile along filter medium versus filtration velocity （ranging from 3 to 7cm/s）, particle c...Alumina （MMAD： 32.45μm） was used to study dust cake formation in fiber filter at steady-state operation. Cake vertical profile along filter medium versus filtration velocity （ranging from 3 to 7cm/s）, particle concentration （ranging from 40 to 120g/m^3） and particle areal mass to filter （ranging from 0.57 to 2.86 kg/m^2）, was researched by experiments and modeling. The filtration was carried through by a plane filter media （Material： Terylene felt, Thickness： 1.8mm） covered on a framework which was fixed in a filter. During filtration, the cake thickness was measured up and down by a mobile microscope and a camera controlled by a PC. The results showed that the cake vertical profile accord with a peak function. The peak amplitude A, center displacement xc, the shape parameters W of the peak function was greatly depended on filtration velocity and particle areal mass to filter, whereas slightly on particle concentration. The relationships between the three coefficients （peak amplitude A, center displacement xc, the shape parameters W） and filtration velocity, areal mass to filter, particle concentration were associated as equations, based on which pressure drop model was deduced. The peak function and pressure drop model were verified with experimental data.展开更多
To study the effects of particle motion mechanism and size distribution on fractal dimension of dust cake structure,the process of aerosol particles deposition in fibrous filtration medium was simulated on basis of Di...To study the effects of particle motion mechanism and size distribution on fractal dimension of dust cake structure,the process of aerosol particles deposition in fibrous filtration medium was simulated on basis of Diffusion-Limited Aggregation(DLA)improving model.In this study,effects of inertia movement and diffusion movement on particles deposition would be considered.In the mean while,ratio of inertia movement to diffusion movement was defined as Pe number.The results show that surface curve of dust cake becomes irregular with Pe reducing and fractal dimension of dust cake surface increased with Pe increasing.The more greater particles dispersion,the more greater dust cake porosity,the more uneven the distribution.The porosity,formed by Polydisperse dust particles,is less than that formed by monodisperse particles.Stronger particle diffusion movement,more uniform the dust cakes was.展开更多
基金Supported by the National Natural Science Foundation of China (No. 50376042)Doctoral Program Foundation of Institute of Higher Education of China (20040425007).
文摘Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the reservoir pressure, and the filtration velocity on the cleaning effectiveness are analyzed. Experimental results show that there exists an optimum dust cake thickness for pulse-cleaning process. For thin dust cake, the patchy cleaning exists and the cleaning efficiency is low; if the dust cake is too thick, the pressure drop across the dust cake becomes higher and a higher reservoir pressure may be needed. At the same time there also exists an optimum reservoir pressure for a given filtration condition.
文摘Alumina （MMAD： 32.45μm） was used to study dust cake formation in fiber filter at steady-state operation. Cake vertical profile along filter medium versus filtration velocity （ranging from 3 to 7cm/s）, particle concentration （ranging from 40 to 120g/m^3） and particle areal mass to filter （ranging from 0.57 to 2.86 kg/m^2）, was researched by experiments and modeling. The filtration was carried through by a plane filter media （Material： Terylene felt, Thickness： 1.8mm） covered on a framework which was fixed in a filter. During filtration, the cake thickness was measured up and down by a mobile microscope and a camera controlled by a PC. The results showed that the cake vertical profile accord with a peak function. The peak amplitude A, center displacement xc, the shape parameters W of the peak function was greatly depended on filtration velocity and particle areal mass to filter, whereas slightly on particle concentration. The relationships between the three coefficients （peak amplitude A, center displacement xc, the shape parameters W） and filtration velocity, areal mass to filter, particle concentration were associated as equations, based on which pressure drop model was deduced. The peak function and pressure drop model were verified with experimental data.
文摘To study the effects of particle motion mechanism and size distribution on fractal dimension of dust cake structure,the process of aerosol particles deposition in fibrous filtration medium was simulated on basis of Diffusion-Limited Aggregation(DLA)improving model.In this study,effects of inertia movement and diffusion movement on particles deposition would be considered.In the mean while,ratio of inertia movement to diffusion movement was defined as Pe number.The results show that surface curve of dust cake becomes irregular with Pe reducing and fractal dimension of dust cake surface increased with Pe increasing.The more greater particles dispersion,the more greater dust cake porosity,the more uneven the distribution.The porosity,formed by Polydisperse dust particles,is less than that formed by monodisperse particles.Stronger particle diffusion movement,more uniform the dust cakes was.
