• Proceedings of the KSME Conference
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• 2001.11b
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• pp.670-675
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• 2001

This paper describes aerodynamic preliminary design performance prediction and flow analysis for turbine of the marine middle engine turbocharger. The performance characteristics of turbocharger turbine are investigated at various operating conditions using mass flow rate and computational flow analysis for rotor and nozzle at design point are performed. Preliminary design results are performed by applying mean line and radial equilibrium theory. Performance prediction and flow analysis results show good agreement with experiments. From 3 dimensional flow analysis result, efficiency is 0.6% greater than design point. Therefore, this design approach is useful for preliminary design, and helps to increase the design capability for optimized rotor blade.

• 연구논문집
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• s.27
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• pp.15-34
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• 1997

The 3-dimensional unsteady compressible flows around the high speed train have been simulated for the train entering a tunnel and for passing another train. The simulation method employs the implicit approximation-factorization finite difference algorithm for the inviscid Euler equations in general curvilinear coordinates. A moving grid scheme is applied in order to resolve the train movement relative to the tunnel and the other train. The velo-city and pressure fields and pressure drag are calculated to study the effects of tunnel and the other train. The side directional force which is time dependent is also computed for the passing train. Pressure distribution shows that the compression wave is generated in front of the train noise just after the tunnel entrance and proceeds along the inside of tunnel.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.11
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• pp.3573-3588
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• 1996

The flow through a centrifugal compressor impeller was calculated using the 3-dimensional Navier-Stokes solution method. A control volume method based on a rotating curvilinear coordinate system was used to solve the time-averaged Navier-Stokes equations, and a standard k-.epsilon. model was used to obtain eddy viscosity. Numerical results and experimental data were compared for the overall performance of the impeller, the pressure distributions along the shroud wall and the detailed flowfields at the design and off-design conditions, which showed good coincidence. The flow through the impeller is complex with the curvature of the streamlines and rotation. The development of secondary flows and the jet-wake flow characteristics, which is the main source of flow loss, was discussed. Calculation results show quite different patterns as the flow rate changes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.11
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• pp.1371-1378
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• 1999

Flow through turbomachinery has a very complex structure and Is Intrinsically unsteady. In addition, trend to highly loaded turbomachinery makes the flow extremely complex due to the interaction between rotor and stator. In this study, flows through UTRC LSRR turbine are numerically analyzed using 2 dimensional Navier-Stokes equations. The convective terms of the governing equations are discretized using the Van-Leer's FVS(Flux vector splitting) with an upwind TVD scheme. The conventional central differencing is used to discretize the diffusion terms on the finite volume. The accurate unsteady motion is achieved by using a 2nd order accurate, 3-point Euler implicit scheme. The quasi-conservative zonal scheme is used for calculating the flow variables on the zonal interface between the rotor and stator. The axial gap between stator and rotor has been configured in two variations, 15% and 65% of average chord length. The analysis program is validated using experimental results and the effect of axial gap is examined. The numerical analysis results are presented by time averaged pressure coefficient and pressure magnitude coefficient and compared with experimental results.

• Journal of computational fluids engineering
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• v.13 no.4
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• pp.72-79
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• 2008

This study is to investigate the air flow around a sirocco fan which is used in a range hood. The main object of the study is to improve the flow rate of the fan by analysis of unsteady 3-dimensional incompressible flow. Overall analysis is carried out using CFD method. For this, we used a commercial code, SC/Tetra, and used a sliding mesh method to give the same condition as an actual state. First, verification of the CFD results is done by comparing the experimental data with the numerical data for the suction flow rate. It is confirmed that two results are well consistent. Then for the improvent of flow rate, the effect of shape factors such as diameter ratio of fan, geometry of case, cut-off aperture and guide angle of case exit on the suction flow rate was considered. Especially, for a new design of housing, the principle of Archimedes spiral was used. The overall analysis was applied to a new design of housing, and the result showed an increase of flow rate by 10.7%.

• Journal of computational fluids engineering
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• v.11 no.2 s.33
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• pp.40-48
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• 2006

In the present, The theoretical and numerical results of gas flow characteristics inside a swirl injector are presented. For this purpose a one-dimensional (theoretical) model and 2D/3D CFD models are proposed for use in the design of the injector. It was found that contradictory to the classical theory about the compressible flow, the swirl has a significant effect on the mass flow rate and the choking conditions. It was found that the one-dimensional model provides reasonably accurate results compared with the 2D/3D numerical results, and thus can be used at the initial stage of the swirl-injector design process.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.3
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• pp.311-318
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• 2003

The present work evaluates the effects of mixing vane shape on the flow structure and heat transfer downstream of mixing vane in a subchannel of fuel assembly. by obtaining velocity and pressure fields. turbulent intensity. flow-mixing factors. heat transfer coefficient and friction factor using three-dimensional RANS analysis. Four different shapes of mixing vane. which were designed by the authors were tested to evaluate the performances in enhancing the heat transfer. Standard k-$\varepsilon$ model is used as a turbulence closure model. and. periodic and symmetry conditions are set as boundary conditions. The flow blockage ratio is kept constant. but the twist angle of mixing vane is changed. The results with three turbulence models were compared with experimental data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.519-524
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• 2019

A horizontal dust collector is used in a large wind-volume grain dryer. In this study, Computational Fluid Dynamics (CFD) was used to analyze the flow characteristics inside the dust collector, including the effects of wear on the conical hub on the dust collection performance. Recently, a horizontal cyclone dust collector was developed with a conical hub and fixed vanes at the inlet of the dust collector to generate swirl flow to separate foreign matter from the air. The dust collector is relatively small in size and easy to install, and it has a relatively low back pressure, which does not require any additional power. However, there are problems with a back pressure problem and dust deposition that are caused by the shape of the horizontal dust collector. To solve these problems, the flow characteristics were studied with internal shapes of the dust collector using three-dimensional flow analysis.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.17-23
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• 1995

A numerical analysis on engine coolant is made by the use of FVM based general purpose 3 dimensional Navier-Stokes solver, TURB-3D. Numerical solutions are verified by comparison with the experimental data of Lotus model. The results show a good qualitative as well as quantitative comparison. Coolant flow rate control is attempted through adjusting the cross section area of passage base on the results of an original coolant passage. It is concluded from the results that the flow rate control is possible as attempted, and thus can be used in the real engine design.

• Journal of the Korean GEO-environmental Society
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• v.15 no.3
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• pp.41-48
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• 2014

Experimental study of sedimentation and self-weight consolidation has been primary research area in dredged soil. However, good quality of the dredged soil and minimum water pollution caused by the pumping of reclaimed soil require intensive study of the flow characteristics of dredged material due to dumping. In this study, continuity and the equilibrium equations for mass flow assuming single phase was derived to simulate mass flow in dredged containment area. To optimize computation and modeling time for three dimensional geometry and boundary conditions, depth integration is applied to governing equations to consider three dimensional topography of the site. Petrov-Galerkin formulation is applied in spatial discretization of governing equations. Generalized trapezoidal rule is used for time integration, and Newton iteration process approximated the solution. DG and CDG technique were used for weighting matrix in discontinuous test function in dredged flow analysis, and numerical stability was evaluated by performed a square slump simulation. A comparative analysis for numerical methods showed that DG method applied to SU / PG formulation gives minimal pseudo oscillation and reliable numerical results.