• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.473-478
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• 2010

In this study, the Ergun's equation has been verified in order to calculate pressure drop of the two phase flow. The equation had been used in the high Reynolds number region for interior ballistic analysis in spite of being verified in the low Reynolds number region. Therefore additional verification seems to be inevitable. Thus, the validity of the equation has been verified using CFD in the high Reynolds number cases of the diameter-particle ratio 10, 13 and 16.

• Journal of computational fluids engineering
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• v.16 no.2
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• pp.62-65
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• 2011

Characteristics of the pressure drop in an expanded bed have been compared to those in a packed bed for numerical study of the interphase drag in gas-particle flows. A numerical analysis of the pressure drop by the particle drag has been conducted according to the tube-to-particle diameter ratios and Reynolds numbers for comparison. As the tube-to-particle diameter ratios increase at the same Reynolds number, the pressure drop tends to converge. It has been confirmed that characteristics of the pressure drop in the expanded bed are similar to those in the packed bed.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.13 no.3
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• pp.168-182
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• 1984

For the purpose of drying high moisture rough rice effectively, from the view point of pre-drying, some basic experiments of fluidized bed drying of rough rice were carried out. The minimum fluidization velocities $(U_{mf})$ for both rough rice and glass bead were analyzed to find out fluidizing characteristics. The main results obtained were as follows ; 1) Minimum fluidization velocity of rough rice and glass bead were 2.01m/s and 4.07m/s, respectively, when using the distributor with $16\%$ opening ratio. 2) $U_{mf}$ calculated by Shirai's empirical equation and that calculated by Wen's modified equation were inconsistent with experimental data, while $U_{mf}$ calculated by Ergun's equation was consistent with the experimental data. 3) The following equations, on the basis of Leva's equation, were obtained. $$C_{mf}=1.19\times10^{-4}(Re_p)^{-0.0318)\;(rough rice)$$ $$C_{mf}=1.02imes10^{-4}(Re_p)^{-0.0047)\;(glass bead)$$

• Solar Energy
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• v.12 no.2
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• pp.43-50
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• 1992

This study has been conducted to provide fundamental knowledge of the characteristics of pressure drop through porous metal by experimental investigation. Pressure drop of air passing through porous metal was measured. The influences of porosity and flow velocity on pressure drop were investigated and in view of friction factor, the experimental data was compared with theorical equation as known to Ergun's equation concerning unconsolid packed bed. The result of this study are as follows. The pressure drop was increased with increasing the flow velocity and at the same flow velocity with decreasing the porosity(decreasing the particle diameter), In Particular, the experimental equation for the pressure drop was derived using the particle diameter, matrix diameter and matrix thickness. The experimental data were correlated well(mean deviation ${\pm}15%$ )with the present empirical dimensionless equation.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.41-45
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• 2011

Pressure drops of two-phase flow in a pipe according to particle shapes have been calculated and analyzed. The numerical analysis for 3 cases of Reynolds number has been conducted for each particle shape. In case of the cylinder shape, the particles had been assumed to be randomly distributed for each Reynolds number. The results have been averaged and compared to those of the case of the ball shape. Additionally, pressure drops of ball and cylinder shapes has been compared to the result of Ergun's equation.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.310-314
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• 2009

A numerical code for the interior ballistics has been investigated. The method of the ghost cell extrapolation has been used for the moving boundary with the projectile movement. The porosity effect and the Ergun's Equation have been used in the numerical calculation for the grain combustion. The calculation results of the numerical code have been compared and verified through those of the lumped parameter method. Computerization techniques of the numerical analysis for the interior ballistics have been developed.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.5
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• pp.573-579
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• 2021

In this study, flow analysis was performed on three types of strainers for ships with different flow rates to predict the pressure drop of the strainer due to the filter of strainer. In the case of flow analysis, the flow analysis was performed by applying the porous media method by applying the resistance value derived by Ergun's equation to the filter position. As a result of the analysis, it was found that when the dimensions of the strainer body were small, the influence of the flow rate on the pressure drop was large. In addition, the amount of pressure drop and the flow rate are almost linearly proportional, and an analysis formula that can predict the amount of pressure drop was derived. In order to predict the amount of pressure drop of the strainer when blockage exist in the strainer filter, the analysis was performed by introducing the resistance ratio to derive the prediction equation. Using this equation, it is thought that it will be possible to predict the performance of the strainer due to blockage in the future strainer design and field application.

• Solar Energy
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• v.6 no.1
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• pp.3-11
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• 1986

Minimum fludizing velocities and voidages were investigated for closely sized sand and magnesia particles with mean diameters in the range of $297-841\;{\mu}m$ over the temperature between 15 and $1.000^{\circ}C$. Boundaries between changing behaviour at $Re_{mf}=14$ and Ar=17,000 were observed. In beds of fine particles in Geldart's group "B", the minimum fluidizing velocity ($U_{mf}$) decreased as temperature increased, but not as much as expected on account of the gas viscosity increase, furthermore the increase in the minimum fluidizing voidage (${\in}_{mf}$). With larger particles in group "D", $U_{mf}$ increased, first, with temperature increase because of reduced gas density, and depending on the particle size, $U_{mf}$ reduced as flow conditions moved from turbulent to laminar. Among the correlations predicting $U_{mf}$, Ergun equation agreed best with the experimental data providing that the change in ${\in}_{mf}$ according to temperature is allowed for.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.8
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• pp.82-90
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• 2019

We propose an equivalent model of a sintered metal mesh filter calculated by Ergun's equation and polynomial regression for the CFD analysis of breakaway devices at a hydrogen fueling station. CFD analysis of filters that cause high pressure loss is essential because breakaway devices in high-pressure hydrogen conditions require low pressure loss. A differential pressure experiment with a filter was performed in a low-pressure air condition considering similarities. An equivalent model was developed by deriving the resistance value by the polynomial regression using the experimental results. The results of CFD analysis using the equivalent model show that there was almost no error in the operating condition of the breakaway device compared to the experimental results. Through this work, we believe that the proposed equivalent model of a filter can be applied to the analysis of breakaway devices in hydrogen fueling stations. We will study how to optimize the shape and position of the filter in breakaway devices using the developed equivalent model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.93-105
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• 1993

In this paper, the maximum scour depths at piers located in the Bo Cheong Stream, which is a tributary in the Geum River System, were calculated and compared using 24 local pier scour equations. The equations were classified as six groups by non-dimensional types of equations. The geometric data in the stream bed and pier data at San Seong, Yi Pyung and San Gye, which are IHP data collection stations, were utilized for applying the scour equations. The geometric data in the stream bed were obtained by analyzing the bed material sampled in three stations which are in the left side, middle and right side for stream direction. The maximum flow velocities at maximum flow depths which were measured from 1982 to 1991, were used as the hydraulic flow data. The pier data for predicting pier scour depths were measured in the fields. The maximum pier scour depths calculated using the equations were compared with the held scour depths measured in the streams or rivers in the world. Arunachalam, Shen-Karaki III, Jain-Fischer equations are selected as the proper local scour equations for predicting the maximum local scour depths at piers in the Bo Cheong Stream. Inglis-Lacey and Shen-Karaki II equations are applicable in case of rapid flows conditions in which Froude number is over 0.3. Froehlich, Laursen I, Laursen II, Neill, Melville equations are applicable in the slow flow conditions in which Froude number is less than 0.3. Blench equation or Inglis-Poona equation varies rapidly by changing Froude numbers. Therefore the equations should not be used without careful considerations in selecting the applicable ranges. The maximum local scour depths calculated using Sarma-Krishnamurthy, Ahmad, Coleman, Varzeliotis, Larras, Bata, Chitale, Venkatadri, Basik-Basamily-Ergun, U.S.G.S., Shen I equations are usually less than the scour depths measured in the fields.