• Title/Summary/Keyword: Pressure Drop Reduction Ratio

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Characteristics of Electrostatic Cyclone-Bag Filter with Upper Inlet (상부유입식 전기 Cyclone-Bag Filter의 특성)

  • 여석준
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.2
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    • pp.179-190
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    • 2000
  • The main object of this study was to investigate experimentally the characteristics of electrostatic cyclone-bag filter with upper tangential inlet in order to overcome the low collection efficiency for the submicron particle and high pressure drop which were main problems of general fabric bag filters. The experiment was carried out for the analysis of collection efficiency and pressure drop of electrostatic cyclone-bag filter comparing to those of fabric bag filter with various experimental parameters such as the inlet velocity(filtration velocity) and applied voltage etc. In the results the upper tangential inlet type showed higher collection efficiency for submicron particles below 2 ${\mu}{\textrm}{m}$ in diameter than that of center inlet and over 99.9% for overall collection efficiency. Pressure drop reduction ratios were shown as 40-50% for the applied voltage 0kV by centrifugal force and 70-90% for 20k V by the centrifuga and electrostatic force with the tangential inlet velocity (12-21m/s)

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Characteristics of Cyclone-Bag Filter with Bottom Inlet (하부유입식 원심 여과집진장치의 특성)

  • Yoa, Seok-Jun
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.4
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    • pp.639-650
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    • 2000
  • The main object of this study was to investigate experimentally the characteristics of cyclone-bag filter with bottom inlet to decrease the high pressure drop which was one of main problems of fabric bag filter. The experiment was executed for the analysis of collection efficiency and pressure drop(specially, pressure drop of fabric filter) characteristics of the cyclone-bag filter in comparison with those of general fabric bag filter with various experimental parameters such as the inlet velocity, dust loading and variation of vortex region, etc. In the results, the tangential inlet type showed higher collection efficiency for submicron particles below $1{\mu}m$ in diameter than of center inlet, and over 99% for overall collection efficiency. For the inlet particle concentration $100mg/m^3$, pressure drop reduction ratios were shown as 15~38% with the inlet velocity in case of large bag, while 30~48% for small bag due to the increase of vortex region.

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Effect of Particulate Matter and Ash Amount on Pressure Drop and Flow Uniformity of Diesel Particulate Filter Reduction System (입자상물질과 Ash양이 디젤매연여과장치 내의 배압 및 유동균일도에 미치는 영향)

  • Kim, YunJi;Han, DanBee;Seo, TaeWon;Oh, KwangChul;Baek, YoungSoon
    • Clean Technology
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    • v.26 no.1
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    • pp.22-29
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    • 2020
  • Recently, as the fine dust is increased and the emission regulations of diesel engines have been tightened, interest in diesel soot filtration devices has rapidly increased. There is specifically a demand for the technological development of higher diesel exhaust gas after-treatment device efficiency. As part of this, many studies were conducted to increase exhaust gas treatment efficiency by improving the flow uniformity of the exhaust gas in the diesel particulate filter (DPF) and reducing the pressure drop between the inlet and the outlet of DPF. In this study, the effects of pressure drop by the flow rate and temperature of exhaust gas, DPF I/O ratio, Ash, and PM amount in diesel reduction device were simulated via a 12" diameter DPF and diesel oxidation catalyst (DOC) using ANSYS Fluent. As the flow rate and temperature decreased, the pressure drop decreased, whereas the PM amount affected the pressure drop more than the ash amount and the pressure drop was lower in anisotropic DPF than isotropic DPF. In the case of DPF flow uniformity, it was constant regardless of the various variables of DPF. In ESC and ETC conditions, the filtration efficiency for PM was similar regardless of anisotropic and isotropic DPF, but the filtration efficiency for PN (particle number) was higher in anisotropic DPF than isotropic DPF.

CFD Analysis on Effect of Pressure Drop and Flow Uniformity with Geometry in 13" Asymmetric DPF (13" 비대칭 DPF 내 형상에 따른 배압 및 유동균일도 영향에 관한 전산해석연구)

  • HAN, DANBEE;BYUN, HYUNSEUNG;BAEK, YOUNGSOON
    • Journal of Hydrogen and New Energy
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    • v.31 no.6
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    • pp.614-621
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    • 2020
  • Recently, as the fine dust is increased and the emission regulations of diesel engines are strengthened, interest in diesel soot filtration devices is rapidly increased. In particular, there is a demand for technology development for higher efficiency of diesel exhaust gas after-treatment devices. As part of this, many studies conducted to increase the exhaust gas treatment efficiency by improving the flow uniformity of the exhaust gas in the DPF and reducing the pressure drop between the inlet and outlet of disel particle filter (DPF). In this study, computational fluid dynamics (CFD) simulation was performed when exhaust gas flows into the canning reduction device equipped with a 13" asymmetric DPF in order to maintain the flow uniformity in the diesel exhaust system and reduce the pressure. In particular, a study was conducted to find the geometry with the smallest pressure drop and the highest flow uniformity by simulating the DPF I/O ratio, exhaust gas temperature, inlet-outlet pressure and flow uniformity according to the geometry and hole size of distributor.

Numerical Study on the Flow Characteristics with a Vane-type Static Mixer in the Diesel Exhaust Systems (Vane-type Static Mixer에 의한 디젤차량 배기관 내의 유동 특성에 관한 연구)

  • Kang, Kyoung-Nam;Kim, Man-Young
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.5
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    • pp.36-43
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    • 2012
  • In this work the mixing and flow characteristics of a vane-type static mixer were investigated numerically for the reduction of NOx in the SCR-system of the diesel engines. The mixer was located in the 57 times pipe diameter away from the inlet. The analysis were performed by changing such various parameters as vane shape, angles, blockage ratio and location of the vane. The flow structure through the mixer was characterized by uniformity index and pressure drop. The results show that uniformity index and pressure coefficient are substantially influenced by the vane shape, angle, blockage ratio and position of the vane of the mixer.

Effects of the Moisture Contents of Cut Tobaccos on Loose End of Cigarettes (각초 수분이 궐련의 끝빠짐에 미치는 영향)

  • Yang Burm-Ho;Jung Han-Ju;Ahn Dae-Jin;Kim Yong-Ok
    • Journal of the Korean Society of Tobacco Science
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    • v.27 no.2
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    • pp.201-206
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    • 2005
  • In this work, we studied the effects of the moisture contents of cut tobacco on loose end of cigarettes. The loose end of the cigarette groups decreased with the increase of moisture contents of the cut tobacco and especially the loose end of A and C groups decreased to $31\%\;and\;52\%$ with the increase of $1\%$ moisture contents. $A-13.5\%\;and\;B-14.0\%\;and\; C-14.0\%$ moisture samples showed the increase of the weight ratio of cut tobacco over 1.4mm cut length but the decrease under 1.4mm cut length. We concluded that the main reasons were regarded to reduction of small fragment tobaccos caused by increase of moisture contents and exception of air-suction transport of tobaccos to cigarette making machine. In spite of the moisture increase of cut tobaccos under fixed EPD(encapsulated pressure drop), the hardness of Band C sample groups were maintained constantly except A group. This result means that under fixed EPD, the weight of cut tobacco in cigarette rods increases to compensate the reduction of pressure drop by moisture increase of cut tobaccos.

Numerical Study on the Effects of Pressure Wave Propagation for Tunnel Entrance Shape Change in High-Speed Railways (고속철도의 터널입구 형상변황에 따른 압력파동 현상에 관한 수치적 연구)

  • 목재균;백남욱;유재석;최윤호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.2
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    • pp.50-59
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    • 1997
  • When a front head of train enters a tunnel at a high speed, compression wave is generated at tunnel entrance due to the confinement effect and propagated along the tunnel with sound of speed. The propagated compression wave is reflected at tunnel exit due to abrupt pressure change at passage. The reflected wave is expansion pressure wave. And when the rear head of train goes through the tunnel entrance, another expansion pressure wave is generated and propagated along the tunnel. The pressure drop occurs seriously around train when the two expansion pressure waves come cross on train in the tunnel. In order to reduce the pressure drop, the compression wave front must be controlled because the intensity and magnitude of pressure drop is nearly proportional to that of compression wave at tunnel entrance. This study relates to reduction of the pressure wave gradient with respect to tunnel entrance shape change with various kind of angle and rounding. The results show characteristics of wave propagation in tunnel, usefulness of characteristic curve to estimate proper time domain size in numerical study and measuring time in actual experiment. Also rounding is contributed to improve pressure wave front even if its radius is very small at tunnel entrance. In order to improve of pressure wave front at tunnel entrance, proper angle is prefered to rounding with big radius and an angle of around 14$^{\circ}$ is recommended according to this simulations, And it is expected to reduce additional pressure drop in tunnel when the location and the size of the internal space for attendant equipment are considered in advance.

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Investigation of Characteristics of Electrostatic Bag Filter with Discharge Electrode Shapes and Filter Properties (방전극 형상 및 여과재에 따른 정전 여과집진장치특성에 관한 연구)

  • 김정일;여석준
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.3
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    • pp.237-250
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    • 1998
  • In this study, the characteristics of electrostatic bag filter to overcome the main problems such as the high pressure drop and low collection efficiency for submicron particles are investigated with the experimental parameters. Especially, the experiment is carried out focusing on collection efficiency and pressure drop change mechanism as a function of discharge electrode shapes and filter properties, including the applied voltages, filtration velocities and particle concentrations, etc . Results show that the collection efficiency is improved over 30% for the fine particle below 1 pm and pressure drop reduction ratio (PDRR) increases in the following order 4 mm screwy > 4 mm square > 4mm round discharge electrodes . For the filter properties, Nomex is more effective than PE under the influence of electrostatic force. Applying 30 kV for a screwy discharge electrode, higher overall collection efficiency is maintained in spite of the increment of filtration velocity over four times (8 m/min) in comparison with that of 2 m/min and PDRR are highly shown over 80o1o with various filtration velocities, 5, 8, 11 m/min.

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A Hydraulic and Feasibility Study of New Tower Internal in Gas Processing Plants

  • Choo Chang-upp
    • International Journal of Safety
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    • v.3 no.1
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    • pp.15-19
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    • 2004
  • A new tower internal, which is called CSE, is presented. The CSE is composed of a nozzle perforated in its bottom along the entire periphery and equipped with a multi vane axial swirler at the inlet and hollow cylindrical separator at the outlet of the nozzle. According to the experimental work for obtaining the necessary hydraulic information of the CSE, which is used for preliminary design of a separation column, the CSE showed a stable operation over the wide rage of gas/liquid ratio. However, it caused large pressure drop due to the high gas velocity which should carry liquid droplets through the element. The high pressure drop may cause problems in energy recovery and the application of the CSE can be limited to the high pressure columns. Assuming that the tray efficiency of the CSE is the same with the existing separation columns, the results of the column design showed the size reduction of the column diameters by 30 to $40\%$ and investment cost saving, depending on operating conditions. The application of the CSE to separation column may also contribute to the de-bottlenecking the existing column.

Application of Lumley's Drag Reduction Model to Two-Phase Gas-Particle Flow in a Pipe(I) - Mechanism of Momentum Transfer- (고체분말이 부상하는 2상 난류 수직관 유동에 대한 Lumley의 저항감소 모델의 적용(I) - 운동량 전달 기구)

  • 한기수;정명균;성형진
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.6
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    • pp.1301-1309
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    • 1989
  • 본 연구의 목적은 Lumley의 저항감소 모델을 사용하여 여러 부하도하에서 부유유동의 유동 특성을 관찰하는 것으로, 특히 저항감소가 일어날 때와 일어나지 않을 때의 유동특성을 알아 보고자 한다.