• Spatial Information Research
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• v.20 no.1
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• pp.27-38
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• 2012

The recent development of CFD techniques are being involved w ith Environmental Impact Assessment and Environmental DesignroThey are being applied to the Site Planning and Engineering Design works as a new trendroHowever, CFD laboratory works are not extended to the field works in Industrial Project due to inaccuracy of the data input process that is cause by absence of regional height informationsroHence, in this study, we promote to build a new initial input data processing steps and algorithms for CFD Model generation. ENVI-met model is very popular, efficient, and freely downloadable CFD model. Light Detection And Ranging (LiDAR) are well known state of art technology and dataset proving a reliable accuracy for CFD. We use LiDAR data as a input source for CFD input producing process and algorithm development and evaluation. CFD initial input data generation process and results derived from am development and set is very useful and efficient for rapid CFD input data producing and maklomore reliable CFD Model forec st for atmospheric and climatic analysis for planning and design engineering industry.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.12
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• pp.1175-1183
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• 2013

Even if some CFD software developers and its users think that a state-of-the-art CFD software can be used to reasonably solve at least single-phase nuclear reactor safety problems, there remain limitations and uncertainties in the calculation result. From a regulatory perspective, the Korea Institute of Nuclear Safety (KINS) is presently conducting the performance assessment of commercial CFD software for nuclear reactor safety problems. In this study, to examine the prediction performance of commercial CFD software with the porous model in the analysis of the scale-down APR (Advanced Power Reactor Plus) internal flow, a simulation was conducted with the on-board numerical models in ANSYS CFX R.14 and FLUENT R.14. It was concluded that depending on the CFD software, the internal flow distribution of the scale-down APR was locally somewhat different. Although there was a limitation in estimating the prediction performance of the commercial CFD software owing to the limited amount of measured data, CFX R.14 showed more reasonable prediction results in comparison with FLUENT R.14. Meanwhile, owing to the difference in discretization methodology, FLUENT R.14 required more computational memory than CFX R.14 for the same grid system. Therefore, the CFD software suitable to the available computational resource should be selected for massively parallel computations.

• The KSFM Journal of Fluid Machinery
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• v.4 no.1 s.10
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• pp.38-45
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• 2001

A commercial CFD code is used to compute the 3-D viscous flow field within the impeller of a centrifugal pump. Several preliminary numerical calculations are carried out to determine the influence of the parameters such as the grid systems, the numerical schemes, the turbulence models and the shape of the vaneless diffusers at the design flow rate. The results of the preliminary study are used for the calculation of the off-design flow conditions. The circumferentially averaged results such as the radial and tangential velocities, the exit flow angle, the slip factor, the static pressure and the total pressure are compared with the experimental data at the impeller exit to discuss the influence of the prescribed parameters.

• The KSFM Journal of Fluid Machinery
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• v.16 no.3
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• pp.26-31
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• 2013

In present 3D CFD study, the method for determining leakage and rotordynamic coefficients of a plain-gas seal is suggested by using the relative coordinate system for steady-state simulation. In order to find the effect of pre-swirl speed at seal inlet, pre-swirl velocity is included as a parameter. Present analysis is verified by comparison with results acquired from Bulk-flow analysis code and published experimental results. The results of 3D CFD rotordynamic coefficients of direct stiffness(K) and cross-coupled stiffness(k) show improvements in prediction. As pre-swirl speed at seal inlet increases, k also increases to destabilize system. However, pre-swirl speed at seal inlet does not show sensitivity to the leakage and rotordynamic coefficients of K and damping(C).

• Tribology and Lubricants
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• v.26 no.1
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• pp.37-43
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• 2010

Precise prediction of rotordynamic coefficients for annular type seal of turbomachinery is necessary for enhancing their vibrational stability and various prediction methods have been developed. As the seal passage is designed complicatedly, the analysis based on Bulk-flow concept which has been mainly used in predicting seal dynamics is limited. In order to improve the seal rotordynamic prediction, full Navier-Stokes Equations with turbulent model derived in the seal flow passage have to be solved. In this study, 3D CFD(Computational Fluid Dynamics) analysis has been performed for predicting rotordynamic coefficients of non-contact type annular plain seal using FLUENT. Comparing with the results of Bulk-flow model analysis, the result of 3D CFD analysis shows good agreement.

• Atmosphere
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• v.22 no.1
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• pp.109-115
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• 2012

We parallelized the CFD_NIMR model, which is a numerical meteorological model, for best performance on both of distributed and shared memory parallel computers. This hybrid parallelization uses MPI (Message Passing Interface) to apply horizontal 2-dimensional sub-domain out of the 3-dimensional computing domain for distributed memory system, as well as uses OpenMP (Open Multi-Processing) to apply vertical 1-dimensional sub-domain for utilizing advantage of shared memory structure. We validated the parallel model with the original sequential model, and the parallel CFD_NIMR model shows efficient speedup on the distributed and shared memory system.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.67-70
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• 2012

Many computational fluid dynamic (CFD) simulations have treated the coal kinetics poorly due to large physical domain sizes and high computational complexity, particularly for the recent oxy-coal boilers. Furthermore, some modelers' lack of understanding of the kinetic rate model seems to worsen the simulation accuracy. This study is to suggest the importance of proper use of single-film global kinetic model generally used in CFD code to describe the oxy-fuel combustion of coal char through simple char burnout calculation.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.305-311
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• 2000

A commercial CFD code is used to compute the 3-D viscous flow field within the impeller o( a centrifugal pump. Several preliminary numerical calculations are carried out to determine the influence of the parameters such as the grid systems, the numerical schemes, the turbulence models and the shape of the vaneless diffusers at the design flow rate. The results of the preliminary study are used for the calculation of the off-design flow conditions. The circumferentially averaged results such as the radial and tangential velocities, the exit flow angle, the slip factor, the static pressure and the total pressure are compared with the experimental data at the impeller exit to discuss the influence of the prescribed parameters.

• Tribology and Lubricants
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• v.25 no.3
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• pp.150-156
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• 2009

Precise leakage prediction for annular type seals of turbomachinery is necessary for enhancing their efficiency and various prediction methods have been developed. As the seal passage is designed intricately, the analysis based on Bulk-flow concept which has been mainly used in predicting seal leakage is limited. In order to improve the seal leakage prediction, full Navier-Stokes Equations with turbulent model derived in the seal flow passage have to be solved. In this study, 3D CFD (Computational Fluid Dynamics) analysis has been performed for predicting leakage of various non-contact type anular seals using FLUENT. Compared to the results by Bulk-flow model analysis, experiment, and 2D CFD analysis, the result of 3D CFD analysis shows improvement in predicting seal leakage, especially for the parallel grooved pump seal.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.10
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• pp.843-851
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• 2003

The present paper studies the leakage flow model used in the performance prediction of a scroll compressor. Two leakage flow models, isentropic and Fanno flow model, are studied in detail. Their predictions are also compared with CFD solutions to check the validity as a leakage flow model. Comparison with CFD solutions shows that the isentropic flow model predicts excessive leakage flow rate, while the Fanno flow model shows acceptable agreement with CFD solutions. The excessive leakage flow rate by isentropic flow model results in under-prediction of the overall performance of a scroll compressor.