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압력용기로부터 압력방출장치를 통한 가스 방출에 관한 포괄적 고찰
정창복,Chung, Chang-Bock 한국안전학회 2020 한국안전학회지 Vol.35 No.6
The problem of determining the discharge rates of gases from pressurized vessels through pressure relief devices was dealt with comprehensively. First, starting from basic fluid flow equations, detailed modeling procedures were presented for isentropic nozzle flows and frictional flows in a pipe, respectively. Meanwhile, physical explanations were given to choking phenomena in terms of the acoustic velocity, elucidating the widespread use of Mach numbers in gas flow models. Frictional flows in a pipe were classified into adiabatic, isothermal, and general flows according to the heat transfer situation around the pipe, but the adiabatic flow model was recommended suitable for gas discharge through pressure relief devices. Next, for the isentropic nozzle flow followed by adiabatic frictional flow in the pipe, two equations were established for two unknowns that consist of the Mach numbers at the inlet and outlet of the pipe, respectively. The relationship among the ratio of downstream reservoir pressure to upstream pressure, mass flux, and total frictional loss coefficient was shown in various forms of MATLAB 2-D plot, 3-D surface plot and contour plot. Then, the profiles of gas properties and velocity in the pipe section were traced. A method to quantify the relationship among the pressure head, velocity head, and total friction loss was presented, and was used in inferring that the rapid increase in gas velocity in the region approaching the choked flow at the pipe outlet is attributed to the conversion of internal energy to kinetic energy. Finally, the Levenspiel chart reproduced in this work was compared with the Lapple chart used in API 521 Standatd.
정창복,강성주,한정우,백욱진 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.2
후리에(Fourier) 변환의 단점을 극복하고자 개발된 웨이브렛(wavelet) 변환은 여러 연구분야(de-noising, 자료압축, 편미분 방정식의 해석 등)에서 다양한 용도로 활용되고 있다. 그 중 de-noising은 웨이브렛 변환의 대표적인 응용분야 중의 하나로서 최근 활발한 연구가 진행되고 있다. De-noising 효과는 사용하는 shrinkage 함수와 이에 적용되는 threshold 값을 선택하는 방법에 달려있다. 본 연구에서는 서로 다른 특성을 갖는 신호와 잡음의 크기에 따라 여러 threshold 알고리듬을 적용시킨 결과를 서로 비교하고, 그 응용으로 de-noising의 여러 알고리듬을 이용하여 잡음을 제거한 신호와 그렇지 않은 신호를 시스템 식별(system identification)에 적용시켜 그 성능을 서로 비교하였다. The wavelet transformation, which was developed in order to overcome the defects of traditional Fourier transformation, is applied to many Gelds of study in various ways-for example, de-noising, data compression and mathematic applications such as solving partial differential equations, etc. De-noising is one of the main application areas of the wavelet transformation and has been studied by many researchers. The effect of de-noising depends upon the shrinkage function and the method of choosing the threshold value for the function. The objective of this work is to analyze the results of applying various threshold algorithms according to characteristics for signals and noise level. By applying the de-noising to the system identification, we compared the performances of signals which went through the de-noising process with those of signals without de-noising.
정창복 한국사회체육학회 1993 한국사회체육학회지 Vol.1 No.-
사회체육 시설(Agency/Facility)을 먼저 정의해 보고, 그런 시설이나 조직(organization)을 경영(management)하고, 운영(operation)하는데 필요한 최근의 경영개념(concepts), 기술(skills) 그리고 실제적으로 매일 일어나는 현상(practices)들을 검토해 보면서, 추세에 맞는 우리 사회체육 경영의 진로를 생각해 보기로 한다.