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조절링의 위치에 따른 안전밸브의 동적거동에 대한 전산해석
신병수(B.S. Shin),장원준(W.J. Chang),도규식(K.S. Do) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.5
This paper presents a study of dynamic characteristics of safety valve on the position of adjust ring from the CFD analysis on 2D simplified modeling using CFX code. The major concerns in this study are comparisons of flow field and closing pressure of safety valve on the position of adjust ring. And the closing pressure of asymmetric adjust ring was also estimated. To simulate specific fluid characteristics such as sudden expansion and contraction, the working fluid is compressible steam using real gas model. And to simulate the dynamic behavior of valve disc, the force balance equation was applied to the analysis using CEL expression. As a result, it is conformed that the dynamic characteristics between the position of adjust ring and the closing pressure coincided with the valve original design and the closing pressure of asymmetric adjust ring was different from original value.
오리피스 유량계의 입구 속도 분포에 따른 유량 계측 왜곡 특성
신병수(B. S. Shin),김남석(N. S. Kim),이상규(S. K. Lee),배용범,금오현(O. H. Keum) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.5
In this numerical analysis, the distortion of flow measurement by inlet velocity profile of orifice flowmeter was investigated. To validate the numerical method, the convergence was monitored and the grid dependency was also checked. realizable κ-e model was selected and y+ was about 50 in this calculation. the results shows that the pressure at the pressure tab near pipe wall was changed by inclined inlet velocity profile and it leads to distorted a measurement values of flow through the orifice plate from -3.8% to 9%. Therefore, the fully developed inlet flow was required for accurate flow measurement by orifice flowmeter. If not, the orifice plate installed at wrong location should be re-installed or additional actions should be taken.
단일 수평관을 가지는 저장조 내의 이상 유동 열전달 계산
신병수(Byungsoo Shin),정애주(Ae Ju Cheong),장현섭(Hyun Sop Chang) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
Generally, to predict overall heat transfer of heat exchanger including tube bundle, the study on the heat exchanger with a single tube should be preceded. The objective of this study is to calculate the heat flux and the heat transfer coefficient at the inside and outside of a heat exchanger tube using previous heat transfer correlations under a certain given condition. The different correlations were applied to calculation according to two phase flow pattern of horizontal flow inside a tube and the onset of nucleate boiling outside a tube. And the sensitivity study was conducted about the thermal hydraulic parameters near the outside of horizontal tube. Finally, the major effective parameters were investigated.
수평형 응축열교환기에서 이상유동양식에 대한 유량분배의 영향 평가
신병수(Byungsoo Shin),김남석(Namseok Kim),설광원(Kwang-won SEUL),도규식(Kyusik Do) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
In this study, it was performed to estimate effects of flow distributions on two-phase flow patterns in horizontal condensation heat exchanger. Detailed flow fields were calculated using commercial CFD code assuming working fluid as a single phase flow at simplified geometry. The results shows the differences of mass flow rate between heat exchanger tubes could be up to about 40% depending on averaged mass flow rate and features of geometry. At Tandon map which is one of well-known two-phase flow pattern map especially for horizontal condensation tubes, the differences could lead to the change of two-phase flow patterns. It means that performance of heat exchanger and criteria of water hammer also could be changed. Therefore, the effect of flow distribution was considered at design of horizontal condensation heat exchanger.
MARS-KS를 이용한 수평형 응축열교환기의 저장탱크 내의 열유동 특성 예측
신병수(Byungsoo Shin),설광원(Kwang-won SEUL),도규식(Kyusik Do) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
For the performance of a horizontal condensation heat exchanger, the flow characteristics in the storage tank are important factors to determine the heat transfer rate outside the tubes. The objective of this work is to predict the heat transfer rate and flow characteristics outside the heat exchanger tubes using MARS-KS code. To eliminate the effect of condensation heat transfer inside the tubes, the experimental results on temperature profiles were applied to the inside wall of tubes as boundary conditions. In conclusion, the numerical results of MARS-KS had good predictions with experimental results on heat transfer coefficients.
초음파 물체 이송시스템에서 Flexural Beam 의 형태 변화에 따른 이송특성에 관한 연구
신병수(Byung Su Shin),정상화(Sang Hwa Jeong),차경래(Kyung Rae Cha) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
In the semiconductor and the optical industry, a new transport system which can replace the conventional<br/> sliding system is required. These systems are driven by the magnetic field and the conveyer belt. The<br/> magnetic field damages semiconductor and contact force scratches the optical lens. The ultrasonic wave<br/> driven system can solve these problems. In this paper, the object transport system using the excitation of<br/> ultrasonic wave is proposed. The experiments for finding the optimal excitation frequency, finding phasedifference<br/> between two ultrasonic wave generators are performed. The relationship of transporting speed<br/> according to the change of flexural beam shape is verified. In addition, the system performance for practical<br/> use is evaluated.
신병수(Byoung Soo Shin),이병용(Byeung Yong Lee),김영현(Young Hyun Kim) 대한두경부종양학회 2001 대한두경부 종양학회지 Vol.17 No.1
Pituitary apoplexy resulting from hemorrhage or necrosis of a pituitary tumor with subsequent compression of the optic nerves and cavernous sinuses is a life-threatening condition. The diagnosis is made clinically by the sudden onset of headache, meningismus, visual impairment, and ocular abnormalities, Modern surgical techniques seem to have reduced morbidity. Nevertheless, it is evident that not every patient requires surgical decompression after pituitary apoplexy because of spontaneous resolution after hormonal replacement therapy. We report an 84-year-old man who had pituitary apoplexy presenting with headache, ptosis and eyelid swelling. A good result has been achieved with immediate replacement of steroid.