• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 추계학술발표회논문집(1)
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• pp.423-428
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• 1995

Simulation models have been developed to predict the overall behavior of the CANDU plant systems during normal operational transients. For real time simulation purpose, simplified thermal hydraulic models are applied with appropriate system control logics, which include primary heat transport system solver with its component models and secondary side system models. The secondary side models are mainly used to provide boundary conditions for primary system calculation and to accomodate plant power control logics. Also, for the effective use of simulation package, hardware oriented basic simulation network has been established with appropriate graphic display system. Through validation with typical plant power maneuvering cases using proven plant performance analysis computer code, the present simulation package shows reasonable capability in the prediction of the dynamic behavior of plant variables during operational transients of CANDU plant, which means that this simulation tool can be utilized as a basic framework for full scope simulation network through further improvements.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.84-90
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• 2000

Integrated tools are developed for the analysis of the aerodynamic performance and aeroacoustics of helicopter rotors. Heli-NK(Helicopter Navier-Stokes & Kirchhoff) code is for hovering and heli-PA(Helicopter Panel & Acoustic analogy) for forward flight. The former showed its ability to predict the hovering efficiency and high-speed impulsive noise level. Thrust calculation, noise levels, and noise directivity patterns are investigated to confirm the availability of the latter. With some proper validation and improvements. these codes will be more useful and practical.

• 한국가시화정보학회지
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• 제10권3호
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• pp.42-47
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• 2012

Experimental data for the flows in a mixing tank with a bottom agitator are useful for the validation of CFD commercial code. A hybrid volume PIV measurement technique was constructed to measure the flows inside of the mixing tank. The measurement system consists of three cameras. An agitator was installed at the bottom of the tank and it rotates clockwise and counterclockwise. Using the constructed measurement system, instantaneous vector fields were obtained. A phase averaging technique was adopted for the measured instantaneous three-dimensional velocity vector fields. Turbulent properties were evaluated from the instantaneous vector fields.

• Steel and Composite Structures
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• 제8권1호
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• pp.35-52
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• 2008

The paper investigates the seismic performance of a Partially-Restrained (PR) steel-concrete composite frame using the probabilistic approach. The analysed frame was tested at the ELSA laboratory of the Joint Research Centre of Ispra (Italy), while the representative beam-to-column composite connections were tested at the Universities of Pisa, Milan and Trento (Italy). The component modelling of both interior and exterior composite joints is described first, including the experimental-numerical validation. The Latin Hypercube method has been used to draw the probabilistic distribution curves of joints, and then the whole PR composite frame has been analysed. Pushover and incremental dynamic analyses have been carried out using the non-linear FE code SAP2000 version 9.1. The fragility and performance curves of the PR composite frame have been determined for four damage limit states.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.206-209
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• 2011

During landing approach, an airplane could experience dynamic unstable motion by the combination of a gust and elevator control to cancel the disturbances. This situation is dangerous and could lead to a loss of an airplane. In this paper, numerical analysis was used to study the effect of pitch oscillating 2-D high lift devices in a landing condition. Experimental data on a pitching naca0012 airfoil was used for code validation. Dynamic characteristics of an airfoil, single slotted flap for mid-class passenger aircraft were analyzed. Unsteady Navier-Stokes analysis was performed with Spalart-Allmaras turbulence model for separation dominant low speed flow. As a result, flow hysteresis of a flapped airfoil was more complex than that of an oscillating airfoil. So, dynamic analysis of a flap in a landing condition is very important for operational safety.

• Journal of Mechanical Science and Technology
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• 제16권4호
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• pp.522-531
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• 2002

In order to study the thermal-hydraulic behavior of the cable-in-conduit-conductor (CICC), a numerical model has been developed. In the model, the high heat transfer approximation between superconducting strands and supercritical helium is adopted. The strong coupling of heat transfer at the front of normal zone generates a contact discontinuity in temperature and density. In order to obtain the converged numerical solutions, a moving mesh method is used to capture the contact discontinuity in the short front region of the normal zone. The coupled equation is solved using the finite element method with the artificial viscosity term. Details of the numerical implementation are discussed and the validation of the code is performed for comparison of the results with thse of GANDALF and QSAIT.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1998년도 춘계 학술대회논문집
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• pp.110-115
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• 1998

An axisymmetric Navier-Stokes procedure has been developed to analyze the pulse jet flow in a ceramic filter unit for the dust dislodging process. Using Baldwin-Lomax turbulence model as a closure relationship, the SIAF(Scalar Implicit Approximate Factorization) algorithm together with the ${\delta}^k-Correction$ iterative time marching scheme is adopted to solve the unsteady compressible Navier-Stokes equations. After some validation tests, the code has been applied to solve the pulse jet flow and examine the effects of geometry and reservoir pressure condition on the pressure level inside the filter unit. To avoid dealing with the uncertainty of such factors as the cohesion of the collected dust and the adhesion of the dust to the medium and also to simplify the analysis, the filter wall is assumed to be impermeable. The results for various test cases are presented.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.919-924
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• 2000

Spray impingement model and fuel film formation model were developed and incorporated into the computational fluid dynamics code, STAR-CD. The spray/wall interaction process were modelled by considering the change of behaviour with surface temperature condition and fuel film formation. We divided behaviour of fuel droplets after impingement into stick, rebound and splash using Weber number and parameter K. Spray impingement model accounts for mass conservation, energy conservation and heat transfer to the impinging droplets. A fuel film formation model was developed by Integrating the continuity, the Navier-Stokes and the energy equations along the direction of fuel film thickness. The validation of the model was conducted using diesel spray experimental data and gasoline spray impingement experiment. In all cases, the prediction compared reasonably well with experimental results. Spray impingement model and fuel film formation model have been applied to a direct injection diesel engine combustion chamber.

• International Journal of Aeronautical and Space Sciences
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• 제1권2호
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• pp.22-29
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• 2000

A method to simulate the gas turbine transient behavior is developed. The basic principles of the method and main input data required are described. Calculation results are presented in terms of whole operating regime of the engine. The influence of initial parameters such as starting engine power, moment of inertia of the rotor, fuel schedule on performance characteristics of gas turbine during transient operation is shown. In addition, the effect of bleeding air on transient behavior is also considered. For validation of the developed computer code, a comparative analysis with experimental data obtained from a heavy duty gas turbine is made. Calculation results agree well with the experimental data for the range of operating regime studied and proved applicability of the developed technique to initial design stage of control system.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.143-146
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• 2009

The metal-supported SOFC has beed developed as a new concept of SOFC which has higher mechanical strength. However, the mass transfer rate in this type of SOFC may be decreased due to the contact layer and the support layer and that can cause the low performance. Therefore, numerical analysis of the heat and mass transfer characteristics in a metal-supported solid oxide fuel cell(SOFC) is studied in this paper. Governing equations and electrochemical equations are calculated simultaneously. And the numerical results are compared with the experimental results for the code validation. The current density, temperature, and pressure drop are suggested as numerical results.