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.

Numerical study of fluid behavior on protruding shapes within the inlet part of pressurized membrane module using computational fluid dynamics

Changkyoo Choi,Chulmin Lee,No-Suk Park,In S. Kim 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.4

This study analyzes the velocity and pressure incurred by protruding shapes installed within the inlet part of a pressurized membrane module during operation to determine the fluid flow distribution. In this paper, to find the flow distribution within a module, it investigates the velocity and pressure values at cross-sectional and outlet planes, and 9 sections classified on outlet plane using computational fluid dynamics. From the Reynolds number (Re), the fluid flow was estimated to be turbulent when the Re exceeded 4,000. In the vertical cross-sectional plane, shape 4 and 6 (round-type protrusion) showed the relatively high velocity of 0.535 m/s and 0.558 m/s, respectively, indicating a uniform flow distribution. From the velocity and pressure at the outlet, shape 4 also displayed a relatively uniform fluid velocity and pressure, indicating that fluid from the inlet rapidly and uniformly reached the outlet, however, from detailed data of velocity, pressure and flowrate obtained from 9 sections at the outlet, shape 6 revealed the low standard deviations for each section. Therefore, shape 6 was deemed to induce the ideal flow, since it maintained a uniform pressure, velocity and flowrate distribution.

A Computational Study of Wall Effects on the Aeroelastic Behavior of Spanwise Flexible Wings

Namhun Lee,이승수,조해성,신상준 한국항공우주학회 2019 International Journal of Aeronautical and Space Sc Vol.20 No.3

In this paper, we present a computational aeroelastic analysis of flexible flapping wings in the vicinity of solid walls. The wall effects change the aerodynamic forces and moments of the wings, and thus the aeroelastic behavior. The numerical simulation is carried out using a fluid–structure interaction framework by coupling the computational fluid dynamics and computational structural dynamics. A preconditioned Navier–Stokes solver based on a finite volume method is used for the aerodynamic analysis. The structural analysis is performed using a nonlinear structural model based on a geometrically exact beam formulation. The method is validated using previous numerical and experimental results. The aeroelastic characteristics of the flexible wings with and without the walls are computed and compared.

Computational Fluid Dynamics를 활용한 점/접착 생산 공정 내 Jacketed Vessel 설계 최적화

주종효 ( Chonghyo Joo ),박현도 ( Hyundo Park ),조형태 ( Hyungtae Cho ),김정환 ( Junghwan Kim ) 한국공업화학회 2020 공업화학 Vol.31 No.6

점/접착제 생산 공정은 배합 과정에서 mineral insulated (MI) cable을 통해 내부 용액을 76 ℃까지 가열 및 혼합 후 제품출하를 위해 30 ℃까지 상온 냉각을 진행한다. MI cable을 이용한 반응기의 경우, 냉각시간이 평균 10 h 소요되어 생산효율이 낮은 문제점이 있지만, jacketed vessel을 설치하면 위의 문제를 효과적으로 해결할 수 있다. 그러나 jacketedvessel의 종류가 다양해 jacket을 설치하기 전, 배합 공정조건에 적합한 종류를 찾아야 한다. 본 연구에서는 생산효율에 영향을 주는 냉각시간을 최소화하기 위해 computational fluid dynamics (CFD)를 이용하여 jacket 종류에 따른 냉각시간을 비교해 공정에 적합한 jacketed vessel 모델을 개발하고, 점/접착제 생산 공정에 최적화된 jacketed vessel을 설계하였다. 연구 결과, jacket의 높이가 같을 때, half-pipe coil jacket보다 plain jacket의 냉각 성능이 32.7% 더 우수하였고, plainjacket에 60% spiral baffle을 설치하여 냉각 공정에 이용할 경우 냉각시간을 80.4%, 작업시간을 25.1% 단축 가능하다. Blending process of adhesive production has a cooling process to cool down the temperature of the solution which was heated up to 76 ℃ with a mineral insulated (MI) cable by 30 ℃ at room temperature. Using a MI cable in the adhesive production process makes the production inefficient because it takes about 10 h for the cooling process. If a jacketed vessel is used instead of the MI cable, it would shorten the cooling downtime without any additional cooling system by using cold water. However, there are various types of jacketed vessels, and thus the most suitable type should be found before set up. In this study, we designed the optimized jacketed vessel for the adhesive production process by calculating the cooling downtime, which impacts production efficiency, as a function of the jacket types using computational fluid dynamics. As a result, the cooling performance of the plain jacket was 32.7% superior to that of the half-pipe coil jacket with the same height. In addition, the plain jacket with 60% spiral baffle reduced the cooling downtime and operating time by 80.4% and 25.1%, respectively.

A numerical study on the feasibility of predicting the resistance of a full-scale ship using a virtual fluid

김관우,백광준,이순현,이준희,권수연,오도한 대한조선학회 2024 International Journal of Naval Architecture and Oc Vol.16 No.-

In general, the resistance of a real ship is estimated using an extrapolation method after doing experimental tests or numerical simulations with a model scale ship. Since the only Froude similarity is applied in the model test and simulation, the flow characteristics between the model and real ships could be different due to the inconsistency of Reynolds number. However, in the Computational Fluid Dynamics (CFD), the Froude and Reynolds numbers can be satisfied simultaneously because a fluid with virtual properties can be applied. This study investigated the effect of turbulence models and scales for a flat plate. And then the hydrodynamic feasibility of using a virtual fluid was investigated through numerical analysis. The resistance performance and flow structure of the ship were analysed by applying the virtual fluid, and they were confirmed how well these values and flow characteristics simulate the full-scale with a real fluid. This study shows that the results of a full-scale can be obtained at model scale by applying a virtual fluid instead of full-scale numerical simulations that require more computational resources.

Investigation of a fiber reinforced polymer composite tube by two way coupling fluid-structure interaction

Daricik, Fatih,Canbolat, Gokhan,Koru, Murat Techno-Press 2022 Coupled systems mechanics Vol.11 No.4

Fluid-Structure Interaction (FSI) modeling is highly effective to reveal deformations, fatigue failures, and stresses on a solid domain caused by the fluid flow. Mechanical properties of the solid structures and the thermophysical properties of fluids can change under different operating conditions. In this study, we investigated the interaction of [45/-45]₂ wounded composite tubes with the fluid flows suddenly pressurized to 5 Bar, 10 Bar, and 15 Bar at the ambient temperatures of 24℃, 66℃, and 82℃, respectively. Numerical analyzes were performed under each temperature and pressure condition and the results were compared depending on the time in a period and along the length of the tube. The main purpose of this study is to present the effects of the variations in fluid characteristics by temperature and pressure on the structural response. The variation of the thermophysical properties of the fluid directly affects the deformation and stress in the material due to the Wall Shear Stress (WSS) generated by the fluid flow. The increase or decrease in WSS directly affected the deformations. Results show that the increase in deformation is more than 50% between 5 Bar and 10 Bar for the same operating condition and it is more than 100% between 5 Bar and 15 Bar by the increase in pressure, as expected in terms of the solid mechanics. In the case of the increase in the temperature of fluid and ambient, the WSS and Von Mises stress decrease while the slight increases of deformations take place on the tube. On the other hand, two-way FSI modeling is needed to observe the effects of hydraulic shock and developing flow on the structural response of composite tubes.

다상유동 해석을 위한 전산수치해석 방법의 특성 및 연구사례

정선용 ( Seon-yong Jeong ),이석호 ( Seok-ho Rhi ),이계복 ( Kye-bock Lee ) 충북대학교 산업과학기술연구소 2016 산업과학기술연구 논문집 Vol.30 No.1

Multiphase flows with particles and droplets cover a wide range of applications. Because of the wide variety and importance of multiphase flows in industrial processes, the exact analysis of multiphase flow is required. Computational fluid dynamics is the analysis of systems involving fluid flow, heat transfer and associated phenomena such as chemical reactions by means of computer-based simulation. CFD technique is very powerful and spans a wide range of industrial areas. Application of CFD results in industrial research and design crucially hinges on confidence in its outcomes. There have been significant advances in the science and technology of multiphase flows because of enhanced computational capabilities. Computational fluid dynamics is the analysis of systems involving fluid flow, heat transfer and associated phenomena such as chemical reactions by means of computer-based simulation. The primary objective of this work is to review an characteristics of the CFD numerical methods suitable for the multiphase flows and to present the research cases for practical applications.

Numerical simulation of fluid-structure interaction in a stirred vessel equipped with an anchor impeller

Sarhan Karray,Zied Driss,Hedi Kchaou,Mohamed Salah Abid 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.7

A coupling algorithm is used to compute the equilibrium of a flexible anchor impeller in a stirred vessel. This coupling algorithm is based on a partitioned approach, which consists of three relatively independent modules: the computational fluid dynamics (CFD), the computational structure dynamics (CSD) and the interface. In the CFD module, the Euler formulation was used to account for the moving boundary. In the CSD module, the updated Lagrangian formulation for solving the motion of non-linear structure was used and a static study was adopted. In the interface module, an exchange of the forces and displacements was allowed. The numerical results, such as the velocity field, the turbulent kinetic energy, its dissipation rate, the turbulent viscosity and the mechanical deformation, have been presented. Particularly, we are interested in the study of the static behavior of the anchor impeller and the evolution of the displacement field of the arms during various iterations of our coupling algorithm. Accordingly, if the anchor impeller undergoes a deformation due to the flexion of the arms of the anchor impeller, the numerical results changes slightly from iteration to another. At the end of certain iteration,the anchor impeller becomes deformed and the velocity field is preserved. These results confirm that the fluid has a significant effect on the deformation of the arms of the anchor impeller during mixing depending on the velocity of the anchor impeller and the fluid flow. The numerical results were validated by a comparison with literature data.

유동-구조 연성해석기법을 이용한 풍하중이 관절형 컨테이너 크레인에 미치는 영향에 관한 연구

안태원,이성욱,한동섭,김태형,한근조 한국항해항만학회 2008 한국항해항만학회지 Vol.32 No.2

This study was carried out to the effect of wind load on the structural stability of an articulated type container crane according to the wind direction assuming that 75m/s wind velocity is applied on a container crane using FSI(fluid-structural interaction). To consider fluid phenomenon around the container crane, the wind load was derived by the computation fluid dynamic, and it applied to the FSI which can guarantee an accuracy and a reliability in the design stage for wind resistant structural stability to minimize the damage due to high wind load applied in a container crane with a 'ㄱ' type articulated boom which used in the total height restriction region. Following from this, the reaction force on the each support of a container crane was suggested. ANSYS ICEM CFD 10.0 and ANSYS CFX 10.0 used for computation fluid dynamic, and the ANSYS Workbench 11.0 was used for the fluid-structural interaction. 컨테이너 크레인의 설계 시 적용되는 하중 조건 중에서 풍하중이 가장 중요하게 고려되어지는바, 본 연구는 75m/s의 풍하중이 컨테이너 크레인에 작용 할 때 컨테이너 크레인의 구조적 안정성에 미치는 영향을 보다 정확하게 예측하기 위하여 유동-구조 연성해석을 실시하였다. 컨테이너 크레인에 작용하는 실제 유동현상을 고려하기 위하여 먼저 전산유동해석을 실시하였으며, 이를 통해서 얻어진 풍하중을 구조해석의 하중조건으로 적용하는 유동-구조 연성해석을 통하여 컨테이너 크레인 각 지지점에서의 반력을 도출하고 그 결과를 분석하였다. 사용된 모델은 주변 환경으로 인하여 컨테이너 크레인의 최대 고도가 제한 될 경우 사용되는 관절형 컨테이너 크레인이며 전산유동해석 및 유동-구조 연성해석 프로그램으로는 ANSYS ICEM CFD 10.0과 ANSYS CFX 10.0을 사용하였다.

유동-구조 연성해석기법을 이용한 풍하중이 관절형 컨테이너 크레인에 미치는 영향에 관한 연구

안태원(Tae-Won An),이성욱(Seong-Wook Lee),한동섭(Dong-Seop Han),김태형(Tae-Hyung Kime),한근조(Geun-Jo Han) 한국항해항만학회 2008 한국항해항만학회지 Vol.32 No.1

컨테이너 크레인의 설계 시 적용되는 하중 조건 중에서 풍하중이 가장 중요하게 고려되어지는바, 본 연구는 75m/s의 풍하중이 컨테이너 크레인에 작용 할 때 컨테이너 크레인의 구조적 안정성에 미치는 영향을 보다 정확하게 예측하기 위하여 유동-구조 연성해석을 실시하였다. 컨테이너 크레인에 작용하는 실제 유동현상을 고려하기 위하여 먼저 전산유동해석을 실시하였으며, 이를 통해서 얻어진 풍하중을 구조해석의 하중조건으로 적용하는 유동-구조 연성해석을 통하여 컨테이너 크레인 각 지지점에서의 반력을 도출하고 그 결과를 분석하였다. 사용된 모델은 주변 환경으로 인하여 컨테이너 크레인의 최대 고도가 제한 될 경우 사용되는 관절형 컨테이너 크레인이며 전산유동해석 및 유동-구조 연성해석 프로그램으로는 ANSYS ICEM CFD 10.0과 ANSYS CFX 10.0을 사용하였다. This study was carried out to the effect of wind load on the structural stability of an articulated type container crane according to the wind direction assuming that 75m/s wind velocity is applied on a container crane using FSI(fluid-structural interaction). To consider fluid phenomenon around the container crane, the wind load was derived by the computation fluid dynamic, and it applied to the FSI which can guarantee an accuracy and a reliability in the design stage for wind resistant structural stability to minimize the damage due to high wind load applied in a container crane with a 'ㄱ' type articulated boom which used in the total height restriction region. Following from this, the reaction force on the each support of a container crane was suggested. ANSYS ICEM CFD 10.0 and ANSYS CFX 10.0 used for computation fluid dynamic, and the ANSYS Workbench 11.0 was used for the fluid-structural interaction.