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김진범(J. B. Kim),박경암(K. A. Park),고성호(S. Ko) 한국유체기계학회 2000 유체기계 연구개발 발표회 논문집 Vol.- No.-
Flow through turbine flow meter is simulated by solving the incompressible Navier-Stockes equations. The solution method is based on the pseudocompressibility approach and uses an implicit-upwind differencing scheme together with the Gauss-Seidel line relaxation method. The equations are solved steadily in rotating reference frames and the centrifugal force and the Coriolis force are added to the equation of motion. The standard k-ε model is employed to evaluate turbulent viscosity.
배관 형상이 다회선 초음파 유량계의 특성에 미치는 영향
박경암(K. A. Park),최용문(Y. M. Choi),최해만(H. M. Choi),윤병로(B. R. Yoon),황규보(K. B. Hwang) 한국유체기계학회 1999 유체기계 연구개발 발표회 논문집 Vol.- No.-
Five-path ultrasonic flowmeters (200 and 300 ㎜ diameters) were tested to obtain it's characteristics in a water flow standard system. A five-path ultrasonic flowmeter was installed after various pipe fittings (elbow, valve, tee) or a pump. The distance between flow disturbance source and a flowmeter was main experimental parameter. Without a flow conditioner, a five-path ultrasonic flowmeter shows good characteristics as the distance between flow disturbance source and a flowmeter is longer than 10 diameter of a flowmeter.
임계 노즐을 통하는 기체 유동의 유출계수와 임계 압력비에 관한 연구
김재형(J. H. Kim),우선훈(S. H. Woo),김희동(H. D. Kim),박경암(K. A. Park) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5
The air flow through a critical nozzle with a small throat diameter is significantly affected by viscous<br/> effect. In this paper, computational study using the axisymmetric, compressible, Navier-Stokes Equations is<br/> carried out to analy ze flow characteristic through a critical nozzle at low-Reynolds numbers. The nozzle<br/> throat diameters of D=0.28~4.48mm are used in this study. Computational results are compared with the<br/> previous experimented ones. It is found that the present computational results predict the critical pressure ratio<br/> and the discharge coefficient well. As the diameter of a critical nozzle increases, the discharge coefficient and<br/> critical pressure ratio increase. At the nozzle throat, the displacement and momentum thicknesses of the<br/> boundary layer are obtained by an empirical equation.
정적형 유량계를 이용한 소닉노즐 유출계수 교정 방법에 관한 연구
신진현,강상백,박경암,임종연,정완섭,Shin, J.H.,Kang, S.B.,Park, K.A.,Lim, J.Y.,Cheung, W.S. 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.4
진공용 기체 유동측정 표준기로 사용하고자 소닉노즐을 ISO 9300에서 제시한 사양에 맞추어 목직경 0.03 mm와 0.2 mm의 소닉 노즐을 제작하였다. 한국표준과학연구원에서 진공용 유량측정 장치로 개발된 정적형 유량계를 이용하여 제작된 2종의 소닉노즐의 유출계수를 확장불확도 3% 이내로 교정하였다. 교정된 소닉노즐의 유량 측정범위는 약 0.6~1,800 cc/min 범위를 갖는 것으로 나타났으며, 사용유동 조건에 해당되는 레이놀드 수(Reynolds number) 범위는 26~12,100으로 확인되었다. 이러한 결과는 교정된 소닉노즐을 이용하여 진공공정에서 필요한 극 미세 유량의 정밀측정을 가능하게 한 새로운 연구결과로 판단된다. 교정된 소닉노즐을 이용하여 진공펌프의 배기속도 측정결과는 기 구축된 정적법을 이용한 배기속도 측정결과와 1% 이내의 오차범위내로 매우 잘 일치함을 보였다. 교정된 소닉노즐은 향후 반도체 및 디스플레이 공정에 사용되는 다양한 건식 진공펌프들의 배기속도를 현장에서 간단하게 평가할 수 있는 현장 성능평가 장치에 활용할 예정이며, 현재 공정현장에서 배기속도 측정에 널리 사용중인 MFC를 대체할 수 있을 것으로 예상된다. Sonic nozzles have been a standard device for measurement of steady state gas flow, as recommended in ISO 9300. This paper introduces two sonic nozzles of diameter ${\Phi}$ 0.03 mm and ${\Phi}$ 0.2 mm precisely machined according to ISO 9300. The constant volume flow meter(CVFM), readily set up in the Vacuum center of KRISS. was used to calibrate the discharge coefficients of both nozzles. The calibration results were shown to determine them within the 3% expanded measurement uncertainty. Calibrated sonic nozzles were found to be applicable for precision measurement of steady state gas flow in the vacuum process in the ranges of 0.6~1,800 cc/min. Those flow conditions are equivalent to the fine gas flow with Reynolds numbers of 26~12,100. Those encouraging results confirm that calibrated sonic nozzles enable precision measurement of extremely low gas flow encountered very often in th vacuum processes. Both calibrated sonic nozzles are proven to provide the precision measurement of the volume flow rate of the dry vacuum pump within one percent difference in reference to CVFM. Calibrated sonic nozzles are applied to a new 'in-situ and in-field' equipment designed to measure the volume flow rate of vacuum pumps in the semiconductor and flat display processes. Furthermore, they can provide other applications to flow control devices in vacuum, such as MFC, etc.
최용문(Y. M. Choi),박경암(K. A. Park),최해만(H. M. Choi),이기성(K. S. Lee) 한국유체기계학회 1999 유체기계 연구개발 발표회 논문집 Vol.- No.-
Thermal mass flow meter (TMF) is used measuring the small mass flow rate of gases. Generally, flow rate measuring accuracy of TMF is ±2% of full scale. TMF is manufactured for specified working pressure and specified working gas by customer. If it were applied for different working pressure and gases, flow rate measurement accuracy decreased dramatically. In this study, a TMF tested with three different gases and pressure range of 0.2 MPa to 1.0 MPa. Effect of specific heat cause to increase flow measurement error as much as ratio of specific heat compare with reference gas. Pressure change cause to increase flowrate measurement deviation about -0.2% as the working pressure decreased 0.1 MPa.
송희용(H. Y. Song),박경암(K. A. Park),고성호(S. Ko) 한국유체기계학회 2001 유체기계 연구개발 발표회 논문집 Vol.- No.-
Emergency shut-off valve was developed to shut off natural gas at the front of a gas meter in the house. The shut-off flow rate and differential pressure of this valve was controlled by adjusting the distance between the spool and magnet. Also the spool shape was an important factor in the performance of this valve. The experimental and computational results will be useful for the design having better performance.
임재명(J.M. Lim),박경암(K.A. Park),윤복현(B.H. Yoon),최해만(H.M. Choi) 한국유체기계학회 2007 유체기계 연구개발 발표회 논문집 Vol.- No.-
The aim of this paper is to develop the technology of minute gas flow-rate, which is very important in the fields of semiconductor process and NT(Nano Technology). To reach the aim mentioned above we developed the following measurement method. Firstly, we manufactured several some nozzles of the same throat diameters with the same configuration, and calibrated them by means of the standard measurement system. Then we selected a group of sonic nozzles with the similar characteristics. Lastly, we instituted some nozzles from one nozzle in the upstream and other some nozzles from two nozzles in the downstream. In this way we could all the flow-rates(discharge coefficient) for the some nozzles of the same nominal throat diameter.