http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
회전 원형실린더에 부착된 헬리컬 Strip의 영향에 관한 연구
정호윤(Ho-Yun Jung),이종훈(Jong-Hoon Lee),이연원(Yeon-Won Lee) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
Turbulent Karman vortex street past a circular cylinder causes vibration motion due to periodic flow separation, namely flow induced vibration. This phenomenon restrained the wide use of cylinder type structures in engineering fields. Therefore, several ideas have been tested in order to escape unnecessary periodic motion. Using square type helical strip was selected as our numerical research theme. The unsteady flow development at rotation rates is also of interest in understanding flow separation. It is considered very useful to develop a device for the increase of Magnus effect on a circular cylinder. Large Eddy Simulation based on spatial average had been adopted to conduct many numerical simulations of the flows around a cylinder. It has already been known that this method is more accurate than Reynolds Averaged Navier-Stokes models. The objective of this research is to understand the aerodynamic characteristics of a cylinder with helical strip.
정호윤(Ho-Yun Jung),박재성(Jae-Sung Park),강진수(Jin-Soo Kang),윤희철(Hee-Chul Yun),이연원(Yeon-Won Lee) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
Recently, we have many problems on the process of the sludge. In past, the sewage sludge was treated by reclaimed land or thrown away in the sea. But these methods caused environmental pollution. Today, many researchers are studying various methods for reducing its volume. One of these method, this study is to reduce the moisture of sewage sludge and to solidify it using a dryer and curing equipment. In this research, we investigated about design parameter and operation condition of the equipment The curing equipment reduces the percentage of water content from 30% of dryer to 10%. So, we have to study the curing characteristics and performance of curing equipment. For example, there are internal flow characteristics and change of the percentage of water content. And we investigated the change of data at outlet along the initial condition, temperature, humidity and air flow. Using this data, we achieve the experimental results of curing efficiency by each geometry and operating condition. And we also investigated numerical analysis of internal flow using CFD code. This research is basic study for optimal design of the curing equipment.
원심 오일 정화기의 유동 특성 및 여과효율 증대를 위한 개선연구
정호윤(Ho-Yun Jung),최윤환(Yoon-Hwan Choi),이연원(Yeon-Won Lee),도덕희(Deog-Hee Doh) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4
The centrifugal oil purifier is used in ships for purifying the engine lubrication oil. The momentum needed for the rotation of the cylindrical chamber is obtained by jet injections. The dust particles in the oil are separated by the centrifugal forces moving to the inner wall of the rotating cylindrical chamber body. The dust particles are eliminated when the particles are adsorbed onto the surface of the inner wall of the chamber body. the flow characteristics and the physical behaviours of particles in this centrifugal oil purifier have been investigated numerically and the filtration efficiencies have been evaluated. For the calculations, a commercial code has been used and the SST k-ω turbulence model has been adopted. the MRF(Multiple Reference Frame) method has been introduced to consider the rotating effect of the flows.
MnO2 부착 방식에 따른 3D 프린팅 광합성 전극의 특성 및 성능 분석 연구
정호윤(Ho Yun Jung),김용재(Yong Jae Kim),김선일(Seon Il Kim),윤재형(JaeHyoung Yun),류원형(WonHyoung Ryu) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
Despite the harvesting of photosynthetic electrons (PEs) directly from thylakoid membrane has been studied for decades, practical usage of photosynthetic energy has been limited. One of the challenges is insufficient photosynthetic electrons harvesting due to small surface area of electrodes and inefficient charge storage performance. Here, we 3D printed electrodes with graphene oxide ink and modified its surface with MnO₂ deposition to enhance the extraction of PEs from thylakoids and capacitance of supercapacitors. Deposited MnO₂ layers served as a pseudocapacitive material and modify surface properties of electrode. The structure and surface property of the deposited manganese oxide were investigated by X-ray diffraction analysis and scanning electron microscopy (SEM). The capacitive characteristics of the electrode were studied by cyclic voltammetry and current charge-discharge test. Both capacitive and surface characteristics were influenced by the deposition method of MnO₂. As a result of performance test, highest specific capacitance value of 370F/g and 600 ∕ ㎠ photosynthetic current density were obtained at potentiodynamic deposition at 400mV/s condition. This suggests the excellent supercapacitor and bioanode performance of 3D printed electrode with MnO₂ deposition.
Generation of ray class fields of imaginary quadratic fields
정호윤(Ho Yun Jung) 충청수학회 2021 충청수학회지 Vol.34 No.4
Let K be an imaginary quadratic field other than Q(sqrt(-1)) and Q(sqrt(-3)), and let O_k be its ring of integers. Let N be a positive integer such that N=5 or N≥7. In this paper, we generate the ray class field modulo NO_K over K by using a single x-coordinate of an elliptic curve with complex multiplication by O_K.
정호윤(Ho-Yun Jung),이연원(Yeon-Won Lee),김영덕(Young-Duk Kim) 한국마린엔지니어링학회 2008 한국마린엔지니어링학회 학술대회 논문집 Vol.2008 No.-
The wind turbine system is divided by two types. One is horizontal axis wind turbine and the other is vertical axis wind turbine. Typical types of vertical wind turbine are Darrieus type and Savonius type, etc. The Darrieus type is driven by lift force and Savonius type is driven by drag force. The objective of this study is to investigate the aerodynamic characteristics of a new type vertical axis wind turbine blade as the basic study of a design of a vertical axis wind turbine and to estimate the efficiency of wind turbine.
선박 엔진용 원심 오일 정화기의 유동특성 조사 및 여과 효율 증진에 관한 연구
정호윤(Ho-Yun Jung),박영규(Young-Kyu Park),최윤환(Yoon-Hwan Choi),이연원(Yeon-Won Lee),도덕희(Deog-Hee Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
The centrifugal oil purifier is used in ships for purifying the engine lubrication oil. The momentum needed for the rotation of the cylindrical chamber is obtained by jet injections. The dust particles in the oil are separated by the centrifugal forces moving to the inner wall of the rotating cylindrical chamber body. The dust particles are eliminated when the particles are adsorbed onto the surface of the inner wall of the chamber body. The flow characteristics and the physical behaviours of particles in this centrifugal oil purifier have been investigated numerically and the filtration efficiencies have been evaluated. For the calculations, a commercial code has been used and the SST k-ω turbulence model has been adopted. The MRF(Multiple Reference Frame) method has been introduced to consider the rotating effect of the flows. Under various variables, such as particle size, particle density and rotating speed, the filtration efficiencies have been evaluated. It has been verified that the filtration efficiency is increased with the increments of the particle size, the particle density and the rotating speed of the cylindrical chamber.