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전산유체해석을 활용한 미생물연료전지 산화전극부 유동해석
유재철 ( Jae-cheul Yu ),김홍석 ( Hong-suck Kim ),김병군 ( Byung-goon Kim ),김지연 ( Ji-yeon Kim ) 한국환경기술학회 2012 한국환경기술학회지 Vol.13 No.4
다양한 조건을 대상으로 직접 실험을 통해 최적화된 미생물연료전지(Microbial Fuel Cell; MFC)구조를 결정하고, 설계하기 위해서는 많은 시간과 노력이 소요된다. 따라서, 본 연구에서는 전산유체해석(Computational Fluid Dynamics; CFD)을 이용하여, 다양한 내부구조에 따른 산화전극부내 유동해석을 실시하였다. HRT 2시간 조건으로 전산 모사한 결과, 실험실 조건에서는 L4의 사공간 비율(16.8%)이 상대적으로 낮게 나타났으나, 파일럿 조건에서는 P1의 사공간 비율(39%)이 상대적으로 낮게 나타났다. 격막의 구조를 달리하여, 개수를 증가한 MP1(격막의 개수 18개)의 사공간 비율(20%)이 가장 적은 것으로(80%) 나타났다. 하지만, CFD 결과만으로 최적의 구조를 선정하는 것에는 한계가 있다. 따라서, 추가적인 연구를 통해서, 신뢰성 있는 자료를 확보한다면, 향후, MFC 설계 기초 자료로서 활용할 수 있을 것으로 기대된다. It is required a lot of time and effort to decide and design a optimum microbial fuel cell (MFC) configuration through various experiments. In this study, Fluid performance in anodic compartment was analyzed by computational fluid dynamics. At HRT of 2 h, L4 showed lower the ratio of dead space (16.8%) than the ratio of other configurations in lab-scale. However, P1 showed lower the ratio of dead space (39%) than the ratio of other configurations (53-81 %) in pilot-scale. MP1 with a different type of baffle (18 baffles) showed the lowest dead space of 2%. However, it is limited to select the MFC configuration with only CFD analysis. Thus, it would be used as fundamental data for MFC design, if we get relevant information through further studies.
SCR 전처리 공정 사이클론 내부의 전산입자유체해석 연구
서준형,김양수,김영진,조계홍,조진상 한국에너지학회 2023 에너지공학 Vol.32 No.2
본 연구에서는 시멘트 공정 내 선택적촉매환원법(Selective Catalytic Reduction, SCR) 적용을 위해 4,000 Nm3/hr 급 배기가스 전처리 공정의 전산입자유체해석을 수행하였다. 수치 해석은 화학반응이 없는 350 ℃의 isothermal 조건에서 실제 운전조건을 기반으로 사이클론 내 유체 및 입자 장입량, 입자 입도 분포, 압력 등의 해석 조건을 설정하여 분석하였다. 분석결과 현재 설정된 사이클론 집진효율은 55% 내외이지만 분진 입도, 유속, 집진기의 내경에 따른 인입구, 경계조건 등을 변경하여 실공정에 적용할 경우 보다 높은 효율을 달성할 수 있을 것으로 판단된다.
유한체적법 기반의 격자 볼츠만 해석 기법을 이용한 이차원 압축성 점성 유동 해석
양태호(T.H. Yang),권오준(O.J. Kwon) 한국전산유체공학회 2018 한국전산유체공학회지 Vol.23 No.2
This paper presents a finite-volume based lattice Boltzmann method for simulation of full compressible flows with flexible Prandtl number. The equilibrium distribution function is replaced with circular function where all mass, momentum, and energy is equally distributed along a circle. Two different density distribution functions are newly introduced to develop lattice Boltzmann model for compressible viscous flows. The equilibrium distribution function for the evolution equations can be derived from the integration of the Lagrangian interpolation polynomial, which depends on the configurations of the lattice model in the velocity phase space. Two-dimensional compressible flows in a shock tube were investigated to verify the accuracy of the current lattice Boltzmann method. The lattice Boltzmann method based on circular function was successfully adopted to two-dimenstional unsteady simulations with strong contact discontinuities. The present lattice Boltzmann code is applied to the subsonic laminar flow over an NACA0012 airfoil, and the computed results show fair agreement with the Navier-Stokes solution. The hypersonic flow passing through a cylinder is selected as a test case to verify the performances of the current lattice Boltzmann approach. The present solver gives a reasonable agreement with the continuum-based simulation results for flows including detached normal shock wave near the leading edge. Our results imply that the replacement of the Maxwellian distribution function with circular function may be the suitable approach for the evaluation of compressible viscous flows.
전산공력소음해석을 통한 UH-60 제자리비행 공력소음 연구
박남은(N.E. Park),우철훈(C.H. Woo),최건묵(G.M. Choi),김철호(C.H Kim),이석준(S.J. Yee) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.4
The helicopter development technology is improved by the increasing of computing power and advanced test facilities. The increasing efficiency of fuel consuming by the developing of improved lift-to-drag rotor system is the major issue, the noise reduction for ecology(civil area) and increase of survivability to reduce noise detection(battlefield) also are important. This investigation shows the helicopter external noise flight test methods, conventional military helicopter's(UH-60) experimental results and the numerical modeling method for aero-acoustic of rotor blade and the result of CAA(Computalional Aero-Acoustic) for main rotor blade.
히터 위치에 따른 건식 스크러버 내 열-유동 특성에 관한 수치적 연구
조민철,이예승,정희숙,노정훈 한국전산유체공학회 2022 한국전산유체공학회지 Vol.27 No.4
The fourth Industrial Revolution will increase the demand for 3D NAND due to the development of technologies such as artificial intelligence and big data in the future. In the manufacturing process of 3D NAND, which stacks semiconductors in a stacked structure, the demand for gas for deposition and etching increases compared to 2D NAND. It is important to remove process gas with high efficiency because it causes global warming effects. To this end, the industry is introducing scrubber technology. In this study, the thermal fluid characteristics of a scrubber capable of decomposing and removing nitrous oxide (N2O) used to deposit a silicon dioxide (SiO2) thin film in a semiconductor process were analyzed according to the location of the heater. As a result of the analysis, the pressure and velocity distribution in the scrubber was high in the area of the fluid flowing into the heater, and in terms of heat transfer, the air temperature was found to be affected by the capacity of the heater and the flow rate of the flowing fluid.
전산유체해석을 이용한 열교환형 수증기 개질기의디자인 파라미터 연구
양찬욱,이율호,박상현,양충모,박성진 한국수소및신에너지학회 2016 한국수소 및 신에너지학회논문집 Vol.27 No.1
In this study, CFD model for a Heat Exchange Steam Reformer (HESR) used for a 10kW SOFC system is developed for the design optimization of the HESR. The model is used to explore the effect of design parameters on the performance of the HESR. In the HESR, heat is delivered from the hot gas channel to the fuel channel to supply the heat required for the fuel reforming. In the fuel channel where the fuel is reformed, thermo-fluid dynamics, heat transfer, and chemical reaction are considered to predict the performance of the reformer. The model is validated with experimental data within 2~3% error. The validated model is used for the parametric study of the HESR design. Channel length, channel diameter, and flow direction are selected as the design parameters. The effects of the HESR design parameters on the outlet temperature, outlet H2 mole fraction, and pressure drop across the reformer are presented using the model.
수처리 교반기용 프로펠러의 차원 유동 전산 해석 및 성능 특성 분석
배용균(Y.G. Bae),김대한(D.H. Kim),황승태(S.T. Hwang),문영준(Y.J. Moon) 한국전산유체공학회 2015 한국전산유체공학회지 Vol.20 No.1
In this study, the characteristics of water treatment mixer with various propeller profiles are numerically invesitgated. The computation was conducted by solving the incompressible Navier-Stokes equations on unstructured tetrahedral elements with k-ε turbulence model. It was found that the spreading angle and swirl magnitude of the jet are important factors for the mixer efficiency, since they clearly characterize the propeller and the frontal surface area of the propeller but not so much affected by the skew angle if it exceeds 30 degrees. The case1 and case2 models are found to show the best propeller efficiency. The case2 with low blade angle, however, requires the lowest power input for the same discharge capacity as the case1.
액체로켓 엔진 연소장치 개발에 있어서의 전산유체역학 적용 사례
조미옥(M. Joh),김성구(S.-K. Kim),한상훈(S.H. Han),최환석(H.-S. Choi) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.5
This paper provides a brief introduction to application examples of the computational fluid dynamics to development of combustion devices for domestic liquid-propellant rocket engines. It is demonstrated that multi-dimensional flow analysis and multi-disciplinary combustion/cooling performance analysis can be effectively applied to provide key information on some performance-related design issues for thrust chambers and gas generators. Efforts are being made to understand complex physical phenomena inside these combustion devices, especially near the injection plate, by resolving mixing/combustion characteristics of LOX/kerosene with taking the geometry of liquid-liquid coaxial swirl injectors into consideration.
에어포일 공력 성능 테이블의 자동생성을 위한 GUI 환경의 프로그램 개발
김태우(Taewoo Kim),이관중(Kwanjung Yee),이재원(Jaewon Lee),채상현(Sanghyun Chae),오세종(Sejong Oh) 한국항공우주학회 2007 韓國航空宇宙學會誌 Vol.35 No.8
본 연구에서는 헬리콥터 하중 해석을 위한 통합해석코드에서 사용되는 에어포일의 공력 성능 테이블 작성 자동화를 위한 CUI 프로그램을 개발하였다. 개발 후 상용화를 위해 PC 환경에서 사용이 보편화 되어 있는 윈도우 운영체제 기반으로 프로그램을 개발하였다 또 한, 별도의 과정을 거치지 않고도 계산 과정 및 생성된 격자 표시등의 결과를 확인할 수 있는 후처리 기능을 포함하여 사용자의 편의를 도모하였다. 기 검증된 기존의 전산유체역학 코드를 기본으로 하여 다양한 받음각과 마하수 영역에서 공력해석이 자동적으로 수행 되도록 하였으며, 계산 격자는 에어포일 표면 좌표가 입력되면 자동으로 생성되도록 하였다. FORTRAN 으로 작성된 전산유체역학 코드를 별도의 변환 과정 없이 C++ 기반의 CUI 프로그램과 연동시키기 위하여 Mixed-Language 기법을 사용하였다. This paper describes the development procedure of GUI Program for the automated generation of airfoil performance table used in helicopter comprehensive code. Considering commercialization, the program is developed based on the Windows operating system. In addition, it is aimed to enhance user′s convenience by including embedded postprocessor which enables real-time display of calculation procedure and grid system Using the validated CFD code, the aerodynamic analyses are automated for a given range of Mach number and angles of attack. The computational grid system is designed to generate automatically once the surface coordinates are given. Mixed-Language scheme is employed in order to combine the CFD code in Fortran with C++ based GUI program, which makes the time-consuming code conversion unnecessary.