• Journal of Advanced Marine Engineering and Technology
• /
• 제38권10호
• /
• pp.1251-1256
• /
• 2014

The use of lubrication oil is of many purposes and one among them is to drive the engine mounted on a ship. Hence the supply of clean lubrication oil is important. And an oil purifier is one of key components in marine diesel engines. At present, the element type full-flow oil filter has been widely used for cleaning the engine oil. The self-driven centrifugal oil purifier is a device which is used to remove the impurities in lubrication oil using a jet flow. The flow characteristics and the physical behaviors of particles in this self-driven oil purifier were investigated numerically and the filtration efficiencies were evaluated. For calculations, a Computational Fluid Dynamics method is used and the Shear Stress Transport turbulence model has been adopted. The Multi Frames of Reference method is used to consider the rotating effect of the flows. The influence of centrifugal forcehas been numerically investigatedto improve filtration efficiency of tiny particles. As a result of this research, it was found that the particle filtration efficiency using the only center axis rotating and outer wall rotating system are higher than that of the fully rotating system in the self-driven oil purifier.

• 대한기계학회논문집B
• /
• 제33권10호
• /
• pp.811-819
• /
• 2009

In the present study, deposition of discrete and small particles on a filter fiber was simulated by stochastic method. Trajectory of each particle was numerically solved by Langevin equation. And Lattice Boltzmann method (LBM) was used to solve flow field around the filter collector for considering complex shape of deposit layer. Interaction between the flow field and the deposit layer was obtained from a converged solution from an inner-loop calculation. Simulation method is properly validated with filtration theory and collection efficiency due to different filtration parameters are examined and discussed. Morphology of deposit layer and its evolution was visualized in terms of the particle size. The particle loaded effect on collection efficiency was also discussed.

• Membrane and Water Treatment
• /
• 제15권1호
• /
• pp.31-39
• /
• 2024

The flow in a nanopore of filtration membrane is often multiscale and consists of both the adsorbed layer flow and the intermediate continuum fluid flow. There is a controversy on which interface the slippage should occur in the nanopore filtration: On the adsorbed layer-pore wall interface or on the adsorbed layer-continuum fluid interface? What is the difference between these two slippage effects? We address these subjects in the present study by using the multiscale flow equations incorporating the slippage on different interfaces. Based on the limiting shear strength model for the slippage, it was found from the calculation results that for the hydrophobic pore wall the slippage surely occurs on the adsorbed layer-pore wall interface, however for the hydrophilic pore wall, the slippage can occur on either of the two interfaces, dependent on the competition between the interfacial shear strength on the adsorbed layer-pore wall interface and that on the adsorbed layer-continuum fluid interface. Since the slippage on the adsorbed layer-pore wall interface can be designed while that on the adsorbed layer-continuum fluid interface can not, the former slippage can result in the flux through the nanopore much higher than the latter slippage by designing a highly hydrophobic pore wall surface. The obtained results are of significant interest to the design and application of the interfacial slippage in nanoporous filtration membranes for both improving the flux and conserving the energy cost.

• Korean Chemical Engineering Research
• /
• 제45권3호
• /
• pp.264-268
• /
• 2007

마이크론 금속섬유 필터 표면상에 탄소나노튜브를 직접 합성 성장함으로써 마이크론 필터의 성능을 향상할 수 있었다. 탄소나노튜브는 합성조건에 따라 마이크론 섬유 주위를 덮는 덤불 나노구조체 또는 섬유 사이를 연결하는 망 형상의 나노구조체로 성장하였다. 탄소나노튜브가 성장한 금속필터와 탄소나노튜브가 성장하지 않은 금속필터의 여과성능을 측정하여 비교한 결과, 차압의 변화는 미미하나 여과효율은 더욱 향상되었고, 이는 탄소나노튜브가 오염 나노입자를 잡는 트랩으로 작용하였기 때문이다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
• /
• pp.443-447
• /
• 2001

A laboratory-scale electrodewatering system for enhancing conventional filter pressure dewatering by an electric field has been developed to decrease the water content of sludge generated in the wastewater treatment. It consists of a piston-typed filter press, a power supply and data acquisition system. The offset of electrodewatering is investigated as a function of applied pressure, applied voltage, sludge type and filtration time. Also the optimal conditions for maximizing the dewatering efficiency in the eletrodewatering system are investigated. Electric field strength and mechanical pressure are in the range of from 0 to 120 V/cm and from 98.1 to 392.4 kPa. The dewatering rates increased with increasing electric strength. These experiments produced a final sludge cake with water content of 60 wt% using electrodewatering technology, compared with a 80 wt% using pressure filtration alone. The conventional filtration system using the electrodewatering shows the potential to be effective method for improving dewatering Sludge.

• 한국입자에어로졸학회지
• /
• 제6권4호
• /
• pp.185-192
• /
• 2010

This paper reports that the installation of a carbon fiber ionizer in front of an activated carbon fiber(ACF) filter enhanced the antibacterial efficiency. In addition, the effect of the ionizer on the filtration of bioaerosols is reported. Negative air ions from the ionizer were used as antibacterial agent. The test bacteria(Escherichia coli) were aerosolized using an atomizer and were deposited on the ACF filter media for 10 minutes. E. coli deposited on the filter were exposed to negative air ions for 0, 1, 5 and 10 minutes. Then they were separated from the ACF filter by shaking incubation with nutrient broth for 4 hours. The separated E. coli were spread on nutrient agar plates and incubated at $37^{\circ}C$ for 1~3 days. The antibacterial efficiency of E. coli was measured using a colony counting method. The antibacterial efficiencies of E. coli exposed to negative air ions for 1, 5 and 10 minutes were 14%, 48% and 71%, respectively. The filtration efficiency was evaluated by measuring the number concentration of bioaerosols at the upstream and downstream of the filter media. The increase of filtration efficiency by air ions was 14%, that is similar to the 17% filtration efficiency by none air ions. The ozone concentration was below the detection limit (under 0.01ppm) when the carbon fiber ionizers were on.

• 상하수도학회지
• /
• 제23권1호
• /
• pp.23-30
• /
• 2009

Slow sand filtration (SSF) was the first engineered/mechanical filtration process used in drinking water treatment. In SSF, untreated water slowly percolate through a bed of porous sand. Biological activity within the sand bed have the strongest influence on removal efficiency of pollutants by slow sand filtration. In this study, the microbial population distributions in slow sand filters operated at the various operation conditions was evaluated. The concentrations of $10^4$ to $10^5$ CFU per g dry wt. were observed. No significant differences were seen between the number of filter-covered materials. The data indicate that the temperature has affect on population distribution. Also, the light exposure was influenced on microorganism in slow sand filtration according to the heterotropic plate counts. The role of microorganism within the sand media requires further study.

• 한국대기환경학회지
• /
• 제20권3호
• /
• pp.361-369
• /
• 2004

A metal fiber bed has seldom been applied to the practical filtration process despite its excellent mechanical and chemical stability. The filter-bed used in this work was highly porous with open structure, of which apparent porosity was 80 ∼ 90%. Although pressure loss across the filter-bed was very low, separation efficiency was found to be quite high. This paper focuses on the basic filtration mechanisms of a metal filter-bed and a thin ceramic filter from fly ash for reference. The experimental parameters were face velocity, dust loading and porosity of filter-bed. Pressure drop increased with increasing face velocity and dust feeding load for both filters. It also showed that dust particles deposited in the deep flow path, finally resulting in clogging the pore channels. It thereby indicates that the dominating mechanism of the metal filter-bed would be depth filtration. Meanwhile, the thin fly ash composite filters trapped the aerated dust mainly on the surface of the filter medium, so that the instantaneously formed dust layer might cause a steep increase of pressure drop across the filtration system.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
• /
• pp.597-598
• /
• 2006

Gas filtration at high temperature from industrial processes offers various advantages such as increasing process efficiency, improving heat recovery and materials resource recovery, etc. At the same time, it is an advanced environment protection technology. This paper describes a newly developed metallic filter element. The manufacturing process of sintered $Fe_3Al$ metallic powder and the mechanical and filtration characteristics of this filter element were investigated. In this work, the phase constituent changes of the $Fe_3Al$ powder during sintering were studied. The newly developed filter elements were found to have excellent corrosion resistance, good thermal resistance, high strength and high filtration efficiency.

• International Journal of Vascular Biomedical Engineering
• /
• 제4권1호
• /
• pp.17-26
• /
• 2006

Diabetes mellitus (DM) is a metabolic disorder, characterized by varying or persistent hyperglycemia, which induces several changes in the erythrocyte membrane and its cytoplasm, leading to alteration in the deformability. Techniques applied to measure this are based on filtration of erythrocyte suspension through a membrane and to obtain diffraction pattern under sheared conditions. Ektacytometry requiring less quantity of blood with disposable flow chamber used to measure the deformability of erythrocytes obtained from patients with diabetes and also associated with nephropathy and retinopathy. A decreasing trend of deformability in these patients is observed. The shape parameter form factor, as determined by image processing procedure, increases with the increased of blood glucose levels and shows a pattern similar to filtration time of erythrocyte suspensions through cellulose membranes. Further work is suggested to detect micro-level changes in cell membrane in diabetic patients