• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.328-333
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• 2012

In this study, CFD simulation was performed with commercial CFD code FLUENT for the 3D mixing tank model (1 m in a diameter and 2.5 m in a height) of DME-Propane liquified fuels. Initial condition set-up with existence of DME 146 l at the upper side of mixing tank and Propane 770 l at the lower side of mixing tank. Characteristics of mixture and fluid flow were observed for 34 hours simulation. Two liquid fuel were uniformly mixed within range of 3 mol% after 24 hours, and range of 1 mol% after 34 hours. The simulation result following 4 hours was verified with KOGAS experimental data.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.2
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• pp.97-102
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• 2023

Numerical simulations have been performed to investigate the hydrodynamic characteristics of the rudder since they play an important role in naval architecture fields. Although some values such as hydrodynamics forces can be measured easily in the towing tanks, it is difficult to obtain the detailed information of the flow fields such as pressure distribution, velocity distribution, vortex generation from experiments. In the present study, the effects of hydrodynamic coefficients and Reynolds number acting on the rudder were studied by using Computational Fluid Dynamics(CFD). Ansys fluent, one of commercial CFD solvers, solves the Navier-Stokes equations and the k-epsilon turbulence model is selected for the viscous model to solve RANS equations. At first, drag coefficients and lift coefficient for different angle of attack are obtained by using a CFD commercial code for KCS rudder. Secondly, the 2-D lift coefficients and drag coefficients are compared with 3-D coefficients at the same conditions. Thirdly, the effects of Reynolds number on the hydrodynamic forces are investigated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.279-282
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• 2011

Projectile can be damaged during the storage and handling. Maximum range calculation of the ammunition was performed on the assumption that each projectiles have 1.5mm/3.3mm axisymetric dent on the surface. Drag coefficient for trajectory calculation was delivered from CFD using commercial software FLUENT. In the result of CFD, damaged projectiles those have 1.5mm/3.3mm axisymetric dent have similar drag coefficient compare with normal projectile in the region of subsonic. But, in supersonic region, drag coefficient was increased 3%, 9% each in average. In the result of trajectory calculation, Maximum rage was decreased 1%, 3% each.

• Tribology and Lubricants
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• v.24 no.6
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• pp.291-296
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• 2008

In order to improve the leakage prediction and rotordynamic analysis of an annular seal with a smooth rotor and circumferentially grooved stator, CFD analysis using FLUENT has been performed to determine the groove penetration angle a which is the angle of separation line between control volumes II and III in groove section of Ha and Lee's three-control-volume theory. Validation to the present analysis using new penetration angle determined by the CFD analysis is achieved by comparisons with the results of published Ha and Lee's analysis. For the leakage prediction the present analysis shows slight improvement and CFD results yields the best. Direct damping and cross-coupled stiffness coefficients are predicted better to the experimental ones. However, direct stiffness coefficient is predicted worse.

• Journal of the Korean Electrochemical Society
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• v.6 no.1
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• pp.28-35
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• 2003

A numerical analysis of electrochemical reaction and dynamics of the fluid flow in the channels of a DMFC separator was carried out by using a commercial Computational Fluid Dynamics(CFD) code fluent(ver.6.0). From the simulation work, many valuable informations were obtained in terms of distributions of velocity, pressure, temperature, concentration and current density over the flow field. And it was possible to optimize the flow field structure by using the simulation results. The simulation work using the Cm code was found very helpful in analysing the phenomena occurring in the fuel cell and optimizing the structures of electrodes and flow field.

• Journal of the Korean Geotechnical Society
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• v.28 no.12
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• pp.5-15
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• 2012

In this study, a series of CFD (Computational Fluid Dynamics) numerical analyses were performed in order to evaluate the thermal performance of six full-scale closed-loop vertical ground heat exchangers constructed in a test bed located in Wonju. The circulation HDPE pipe, borehole and surrounding ground formation were modeled using FLUENT, a finite-volume method (FVM) program, for analyzing the heat transfer process of the system. Two user-defined functions (UDFs) accounting for the difference in the temperatures of the circulating inflow and outflow fluid and the variation of the surrounding ground temperature with depth were adopted in the FLUENT model. The relevant thermal properties of materials measured in laboratory were used in the numerical analyses to compare the thermal efficiency of various types of the heat exchangers installed in the test bed. The simulation results provide a verification for the in-situ thermal response test (TRT) data. The CFD numerical back-analysis with the ground thermal conductivity of 4 W/mK yielded better agreement with the in-situ thermal response tests than with the ground thermal conductivity of 3 W/mK.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.3 s.73
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• pp.295-302
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• 2006

In this study, computational structural dynamic analyses of a gyrocopter have been conducted considering unsteady dynamic hub-loads due to rotating blades. 3D CATIA models with detailed mechanical parts we constructed and virtually assembled into the complete aircraft configuration. The dynamic loading generated by rotating blades in the forward flight condition are calculated by a commercial computational fluid dynamics (CFD) code such as FLUENT. Modal based transient and frequency response analyses are used to efficiently investigate vibration characteristics of the gyrocopter. Free vibration analysis results for different fuel and pilot conditions, frequency responses and transient responses for critical flight conditions are also presented in detail.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.8
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• pp.641-648
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• 2016

In this study, the effect of injection nozzle shape on the supersonic film cooling performance is analyzed using CFD. The design parameters are inside and outside angles of upper plate of nozzle and nozzle tip thickness. It is observed that the mass flow rate of film cooling decreases with increase of inside angle, while the effect of the change of mass flow rate on the film cooling effectiveness is relatively small. In addition, cooling performance is generally reduced, except ahead of the local region where shock wave interaction with film cooling occurs, in accordance with the growth of the outside angle and tip thickness. In this paper, the CFD simulation is performed using a commercial software, ANSYS Fluent V15.0, and the CFD model is validated by comparing it with the experimental data shown in preceding research.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.194-201
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• 2017

The KARI-11-180 airfoil was selected as a model for EFD-CFD comparison workshop case 1. Wind tunnel test for this model was conducted in KARI low speed wind tunnel with $0.6m{\times}3.0m$ model for the Reynolds number up to 3.0E6. The model configuration and wind tunnel test results including Cl, Cd and Cp were released at the KSAS 2015 spring conference. The computational analysis results with KFLOW, FLUENT and STAR-CCM+ were present in the KSAS 2015 fall conference. These computational works were summarized in this paper and the comparison results with each others including the wind tunnel data were also summarized.

• 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).