• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.6
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• pp.59-71
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• 2019

The numerical analysis of ablative thermal protection systems (TPS) for solid rockets has been carried out with various in-house codes since the 1960s. However, the application scope of commercial codes has been expanded by adding subroutines and user-defined functions (UDF) to codes such as Fluent, Marc, and ABAQUS. In the past, the flow, thermal response and structural analysis of TPS have been performed using separate approaches. Recently, research has been conducted to interrelate them. In this paper, the thermal response characteristics of thermal protection materials, the in-house codes for thermal response analysis, and the research trends of flow-thermal-structure analysis of TPS using commercial codes were reviewed.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.521-526
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• 2014

현대에 이르러 초경량 무인 비행기에 대한 많은 연구가 진행되고 있다. 이러한 비행체는 저레이놀즈수 영역에서 사용되는 특성으로 인해, 경계층 내에서 박리현상과 난류영역으로의 천이 등과 같은 여러 복합적인 현상을 발생시킴으로써 비행체의 공력특성에 큰 영향을 미친다. Bumpy Airfoil은 저레이놀즈수 유동에서의 이와 같은 문제를 해결하기 위해 제안된 익형이다. 따라서 본 논문은 전산열유체해석 프로그램인 EDISON_전산열유체를 이용하여 Bumpy Airfoil 형상에 대한 공력특성을 연구하였고, 발생하는 양항비를 원 익형과 비교하였다. 비압축성 조건 내에서, 공력 성능 향상을 위한 Bumpy Airfoil의 형상 변수로 Bump 개수와 높이를 선정하여 받음각에 따른 유동장을 분석하고 양항비를 수치해석 및 고찰하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.2
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• pp.93-100
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• 2021

The objective of this research is to evaluate of fire damage for steel-concrete composite bridge superstructure and PSC bridge superstructure under highway bridge exposed to fire loading. To enhance the accuracy and efficiency of the numerical analysis, the proposed heat flow fire analysis method is implemented in ANSYS. The proposed heat flow analysis method is applied to fire damage analysis and performance evaluation for Buchen and Yangsan highway bridge. The result of analysis, temperature of concrete slab and lower flange of steel-concrete composite bridge superstructure are exceed the critical temperature. Also, temperature of slab, lower and upper flange, web of PSC bridge superstructure are exceed the critical temperature. However, the major component, tendon, did not exceed the critical temperature.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.567-572
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• 1997

범용 전산유체해석(Computational Fluid Dynamics) 코드인 CFX-F3D를 이용하여 봉 다발에서의 난류 유동 수치해석을 수행하였다 3$\times$3 봉으로 구성된 부수로 사이의 난류 횡류(Crossflow) 혼합유동과 평행한 4개의 봉으로 이루어진 벽 수로에서의 난류 유동구조를 수치적으로 분석하여 각각의 실험결과와 비교하였다. 부수로 횡류 혼합유동의 경우 예측된 주 유동방향 평균 속도분포는 실험결과와 잘 일치하였으나 벽면과 인접한 부수로에서의 난류강도 분포는 다소 큰 차이가 나타났다. 백수로의 경우 수로 중심선 근처의 주 유동방향의 속도변화는 크게 예측되었고 벽 전단응력은 유로가 협소해지는 영역에서 낮게 예측되었으나 전반적으로 실험결과와 유사한 유동특성을 나타냈다. 이 연구는 봉 다발에서의 난류 유동구조에 대한 이해를 증진시킴과 더불어 CFX-F3D 코드를 평가함으로써 향후 지지격자와 임계열유속 증진장치가 부착된 복잡한 형상의 핵연료 다발에서의 유동장 수치해석의 기반을 마련하였다.

• Fire Science and Engineering
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• v.15 no.2
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• pp.59-79
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• 2001

The paper proposes alternatives for fire safety in architectural planning through heat-smoke distribution related to openings so that we decrease casualty and property loss by fire and lay a great emphasis on building high-rise apartments with consideration of fire safety in Korea. An analysis program(HFA-Heat Fluid Analysis) is built to perform simultaneously numerical analysis and experimental analysis on rooms, units and buildings. In consequence, on the first, fire prevention methods are required to be set up related to openings for design rooms since the flow of heat and smoke is influenced by the type of openings in high-rise apartments. Second, the numerical analysis showed that different planning types cause to show differences in the spreading time of heat and smoke to design the units of high-rise apartments. On the third, each unit building showed different fire behavior depending on openings by numerical analysis and small scaled experiment on heat and smoke flow.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.3-8
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• 2001

LBM은 분자 운동을 직접 모사하지 않고 통계 역학적 원리에 기초하여 주어진 격자 구조 아래서 입자들의 단순 이동, 충돌 과정의 반복에 의해 유동을 모사하는 방법이다. 이미 다양한 열유동 현상들에 대한 응용 결과가 발표되었으며 병렬화, 단순한 프로그래밍 등의 장점으로 인해 앞으로 연소, 다상 유동, micro/nano 스케일 유동 등의 해석에 많은 가능성을 지니고 있다. 아직 국내에서는 이에 대한 소개가 제대로 이루어지지 못해 관련 분야의 연구자들이 충분한 관심을 갖고 있지 않은 것으로 생각되어 본 논문에서 LBM 방법에 대한 개략적인 소개를 시도하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.973-976
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• 2011

In this paper, the conjugated heat transfer anslysis was performed about an electric heater used in a combustion test equipment of a combustor engine to figure out a physical phenomenon that heater coil was periodically cut during heating test. The result of analysis is that the temperature of coil at coil inlet region was increased locally because the velocity of air was slow in that region. The coil of heater was moved to 25mm downstream so that the structure stability of coil was assured by the decrease of the coil temperature due to increase of an air velocity.

• Fire Science and Engineering
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• v.21 no.4
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• pp.18-24
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• 2007

The purpose of this study is focussed on the numerical predictions of temperature distribution by radiation heat transfer in atrium fire using the field fire model and the CCRHT-3D code. This code uses standard $k-{\varepsilon}$ turbulent model with SIMPLE algorithm and weighted sum of gray gases model regrouping(WSGGM-RG). The WSGGM-RG calculates radiative properties on the reduced computational loads while reserving the accuracy. The numerical results show that lower temperature distributions on the wall and the top ceiling wall can be obtained by considering radiative heat transfer. The temperature on the top ceiling wall can be an important parameter in predicting the operating condition of the sprinkler head.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.591-596
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• 2016

Numerical analyses were performed on the heat flow characteristics of a heat transfer plate with six different shapes (basic, rectangle, triangle, wave type) to reduce the level of white smoke at a stack. In this study, to examine the heat transfer performance (heat transfer capacity, pressure drop, turbulence kinetic energy, heat transfer coefficient) on the heat transfer plates, simulations were conducted using the commercial computational fluid dynamics software, ANSYS CFX Ver.14 under uniform flow conditions. The thermal flow phenomenon in a channel with six heat transfer plates could be predicted adequately under uniform flow conditions. The heat transfer capacity, pressure drop, turbulence kinetic energy, and heat transfer coefficient were affected by the flow rate, aspect ratio and plate shape. These results provide guidelines to design an effective heat exchanger with the wave type to reduce white smoke.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.1
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• pp.12-20
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• 2002

An integrated analysis of kerosine/LOX based KSR-III rocket body/plume flowfield has been performed. The analysis has been executed employing three kind of gas thermo-chemical models including calorically perfect gas, multiple species chemically reacting gas, and chemically frozen gas models and their effect on rocket flowfield has been accessed to provide the most appropriate gas thermo-chemical model which meets a specific purpose of performing rocket body and plume analysis. The finite-rate chemically reacting flow solution exhibited higher temperature throughout the flowfield than other gas models due to the increased combustion gas temperature caused by the chemical reactions within the nozzle. All the reactions were dominated only in the shear layer and behind the barrel shock reflection region where the gas temperature is high and the effect of finite-rate chemical reactions on the flowfield was found to be minor. However, the present plume computation including finite-rate chemical reactions revealed major reactions occurring in the plume and their reaction mechanisms and as well.