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재생펌프 임펠러 수치최적화를 통한 형상변수의 영향 고찰
전석윤(Seok-Yun Jeon),김철규(Chul-Kyu Kim),이상문(Sang-Moon Lee),윤준용(Joon-Yong Yoon),장춘만(Choon-Man Jang) 대한설비공학회 2016 대한설비공학회 학술발표대회논문집 Vol.2016 No.6
This work presents a parametric study on the effect of the blade shape of a regenerative pump by using computational fluid dynamics(CFD). A numerical model of a regenerative pump is set through a series of stages including modeling of computational domain, mesh generation, setup of analysis schemes and boundary conditions. As design variables, the height of impeller upper blade and hub are selected for numerical analysis cases. Pressure and torque of the cases are determined numerically in the condition of constant flow rate and angular velocity to derive the pump’s efficiencies. The result shows that torque reduction of the impeller is relatively effective to improve the pump efficiency compared to pressure increase. Effects of the pump blade shapes on the efficiency are also investigated and discussed in detail.
부유 입자를 해석하기 위한 운동량 교환/가상영역-격자볼츠만 방법
전석윤(Seok Yun Jeon),윤준용(Joon Yong Yoon),김철규(Chul Kyu Kim),신명섭(Myung Seob Shin) 대한기계학회 2016 大韓機械學會論文集B Vol.40 No.6
본 연구에서는 격자볼츠만 방법을 기반으로 유체-입자 상호작용에 대한 수치계산을 수행하였다. 유체 유동은 격자볼츠만 방법을 이용하였으며, 유동장 내에서의 고체입자 운동은 계산점(node) 기반의 가상영역으로 간주하여 해석하였다. 유체-입자의 상호작용은 격자볼츠만 방법의 지배방정식에 국부적으로 운동량 교환량을 추가하여 해석하며, 가상영역 내에 위치한 고체입자의 병진 및 회전 운동은 뉴턴운동 방정식과 오일러(Euler) 방정식을 이용한다. 구성된 상호작용 모델의 유효성을 검증하기 위하여 중립상태에서의 부유 입자운동 및 단 입자의 침강에 대한 수치계산을 수행하였으며, 기존 연구들과의 비교를 통하여 본 연구의 유체-입자 상호작용 모델이 갖는 신뢰성과 효용성을 평가하였다. This study presents a Lattice Boltzmann Method (LBM) coupled with a momentum-exchange approach/fictitious domain (MEA/FD) method for the simulation of particle suspensions. The method combines the advantages of the LB and the FD methods by using two unrelated meshes, namely, a Eulerian mesh for the flow domain and a Lagrangian mesh for the solid domain. The rigid body conditions are enforced by the momentum-exchange scheme in which the desired value of velocity is imposed directly in the particle inner domain by introducing a pseudo body force to satisfy the constraint of rigid body motion, which is the key idea of a fictitious domain (FD) method. The LB-MEA/FD method has been validated by simulating two different cases, and the results have been compared with those through other methods. The numerical evidence illustrated the capability and robustness of the present method for simulating particle suspensions.
혼성 격자볼츠만 방법을 이용한 공동 형상 내부에서의 혼합 특성에 관한 수치적 연구
신명섭(Myung Seob Shin),전석윤(Seok Yun Jeon),윤준용(Joon Yong Yoon) 대한기계학회 2013 大韓機械學會論文集B Vol.37 No.7
본 연구에서는 혼성 격자볼츠만 방법(HLBM)을 이용하여 상판이 일정한 속도로 움직이는 공동 형상 내부에서의 혼합 특성에 대하여 수치적으로 연구하였다. 먼저, 공동 형상에서 기존의 신뢰성 있는 유동장 결과와의 비교를 통해 LB-SRT 모델과 LB-MRT 모델의 신뢰성을 검토하였다. 두 모델 모두 기존의 연구결과와 유사한 결과를 보였으나, LB-MRT 모델이 LB-SRT 모델보다 높은 Re수에서는 수치적 안정성이 높은 것을 확인하였다. 수치적 안정성이 좋은 LB-MRT 모델을 토대로 유한차분법을 적용한 HLBM을 이용하여 공동 형상 내부에서의 농도장을 수치 해석하였다. Re수와 Pe수를 변화하여 공동 형상 내부의 혼합 특성과 물질 전달 형태에 대하여 파악하였다. In this study, the mixing characteristics in lid-driven cavity flows were studied numerically by using a hybrid lattice Boltzmann method (HLBM). First, we compared the numerical results from single-relaxation-time (LB-SRT) and multi-relaxation-time (LB-MRT) models to examine their reliability. In most of the cavity flow, the results from both the LB-SRT and the LB-MRT models were in good agreement with those using a Navier?Stokes solver for Re=100?5000. However, the LB-MRT model was superior to the LB-SRT model for the simulation of higher Reynolds number flows having a geometrical singularity with much lesser spatial oscillations. For this reason, the LB-MRT model was selected to study the mass transport in lid-driven cavity flows, and it was demonstrated that mass transport in the fluid was activated by a recirculation zone in the cavity, which is connected from the top to the bottom surfaces through two boundary layers. Various mixing characteristics such as the concentration profiles, mean Sherwood (Sh) numbers, and velocity were computed. Finally, the detailed transport mechanism and solutions for the concentration profile in the cavity were presented.
김민호(Min-Ho Kim),전석윤(Seok-Yun Jeon),윤준용(Joon-Yong Yoon) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
MCV Co. Ltd. developed a triple eccentric butterfly valve (DN600 and PN25) by joint work with Hanyang University. Considering leakage performance and durability of seat for high temperature, solid stainless steel was used for seat material. The 1st, 2nd and 3rd eccentricity of disk were determined by CFD analysis and the value was 82㎜, 9㎜ and 9°, respectively. Jigs for process and assembly were newly designed for the manufacture of prototype valve. The prototype valve was tested by API 598 in order to examine the enclosure performance for shell and seat. The results showed that the leakage rate was zero for both of shell and seat.