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질량 분율 변화에 따른 급유식 압축기 유동특성에 관한 수치적 연구
변순석(Sun-Seok Byeon),이재영(Jae-Yeong Lee),김윤제(Youn-Jea Kim) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
Numerical simulation was carried out to investigate the performance of oil-injected twin screw air compressor according to different mass fraction ratios between oil and air flow. A generalized approach method for numerical simulation was applied which implies the computation of screw compressor thermodynamic process. Numerical analysis was performed using a three-dimensional model with SST turbulent model and implemented by the commercial software, ANSYS Fluent. The dynamic mesh model was adopted to model flows where the shape of the domain is changing with time due to motion on the domain boundaries. The numerical results of volumetric efficiency and discharge pressure were graphically depicted. In addition, the calculated results were compared with existing CFD data and showed a good agreement.
흡입구 형상 변화에 따른 무급유식 트윈 스크류 공기 압축기 성능 특성 연구
변순석(Sun-Seok Byeon),조성욱(Sung-Wook Cho),이재영(Jae-Yeong Lee),김윤제(Youn-Jea Kim) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
A screw air compressor is widely used for medium pressure applications in many industries. It is capable of high speed operation over a wide range of operating pressure and flow rate. Recently, a number of studies conducted to develop the appropriate analysis models. with vast improvements in computational technology and the availability of more accurate calculation methods. The use of CFD models has helped remarkably to evaluate the compressor performance. But, there has been a challenge in CFD modeling of screw compressor to obtain the appropriate rotating mesh systems to secure the sufficient quality to provide realistic results. In this paper, we developed a general approach method to investigate the flow fields in numerical simulation of the twin-screw air compressor. In particular, it is conducted to analyze the performance of newly designed two screw compressors with different shapes of discharge port. The calculated volumetric efficiency was graphically depicted.
캠버각 변화에 따른 소수력 축류 프로펠러 수차의 유동 특성 연구
변순석(Byeon, Sun-Seok),김태윤(Kim, Tae-Youn),한상목(Han, Sang-Meok),김정환(Kim, Jeong-Hwan),김윤제(Kim, Youn-Jea) 한국신재생에너지학회 2012 신재생에너지 Vol.8 No.2
The aim of this paper is to examine the hydraulically optimized camber of a blade. Prior studies have tried to determine the sound method of design on small-hydro turbines. These have appeared to realize a reasonably efficient small-hydro turbine. Nonetheless, specific and accurate design data have not as yet been established for the shape of the runner blade. Hence, this study examines the performance characteristic of an axial propeller turbine with 0~8% camber variations. The results of output power, efficiency, and pressure distribution of the turbine are graphically depicted. The definition of camber refers to the NACA airfoil. The commercial finite element analysis (FEA) packages, ANSYS, and CFX are used in this study. The results revealed the performance characteristics on small-hydro turbine and suggested a highly efficient section shape of the runner.
프로펠러 수차 간극과 피치각 변화에 따른 내부 유동 특성 비교
변순석(S.-S. Byeon),홍창기(C.-K. Hong),김윤제(Y.-J. Kim) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
This article aims to numerically investigate the effects of active flow from the blade tip platform. In addition, the another independent variable is considerable modification of the exit blade tip angles. Using the free vortex theory, and operating with a gross head from 3.5m, the effect of the exit blade tip angles was investigated. It further presented theoretical methodology to analyze the effects of design parameters like the exit blade tip angles and a tip clearance. This paper describes the blade design of an axial propeller hydraulic turbine, and presented the relationship between the layout of the blade profile and the shaft power and efficiency. The results showed that the exit tip modification and tip clearance modification were decreased a significant drop of turbine efficiency about 3~13%.