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주름관에서의 압력강하와 마찰손실 측정에 관한 실험적 연구
윤영선(Youngsun Yun),강준원(Junone Kang),김현정(Hyungjung Kim),유재석(Jaisuk Yoo) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
The data for friction factor of the pipe correlated by Reynolds number and relative roughness has been reported well as a Moody chart. However, the results for corrugated shapes have been not investigated sufficiently. In this research, therefore, the pressure drop and friction factor are obtained. Flexible metal tubes with corrugations for the measurement are made of stainless steel plates. The kinds of tubes for the measurement are 5 annular types and helical types. The pressure drop and the velocity of the flow are obtained by micromanometer & digital pressure sensor, supplying a dry air at several steps. Then the pressure drop was calculated for each tube, using the obtained data. The result showed that the pressure drop is strongly influenced by the viscous dissipation of kinetic energy due to the circulation of flows, rather than a viscous friction loss. The pressure drop increased consistently as the Reynolds number increases.
R-404A/POE 오일 혼합물의 기-액 평형과 상용성에 관한 연구
전필수(Pilsoo Jeon),이광재(Kwangjae Lee),유재석(Jaisuk Yoo),김현정(Hyungjung Kim) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
The vapor-liquid equilibrium and miscibility measurement apparatus was developed and used to obtain data for refrigerant/oil mixture. The vapor-liquid equilibrium and miscibility data for R-404A/POE22 and R-404A/POE32 oil mixtures are obtained over the temperature range from -20 to 60℃ with 10℃ intervals and the oil concentration range from 0 to 90 wt%. Using the experimental data, an empirical model is developed to predict the temperature-pressure-concentration relations for R-404A/POE oil mixtures at equilibrium. In the R-404A/POE22 oil mixture, the average root-mean-square deviation between measured data and calculated results from the empirical model is 3.56% and in the R-404A/POE32 oil mixture, that is 3.24%. Flory-Huggins theory is also used to predict refrigerant/oil mixture behavior. Immiscibility for R-404A/POE22 oil mixture was observed all over the oil concentrations. Immiscibility for R-404A/POE32 oil mixture was observed at the 10~70 wt% of oil concentrations.
윤영선(Youngsun Yun),강준원(Junone Kang),유재석(Jaisuk Yoo),김현정(HyungJung Kim) 한국가시화정보학회 2006 한국가시화정보학회지 Vol.4 No.2
The data for friction factor of the pipe correlated by Reynolds number and relative roughness have been reported well as a Moody chart. However, the results for corrugated shapes have been not investigated sufficiently. In this research, therefore, the pressure drop and friction factor are obtained. Flexible metal tubes with corrugations for the measurement are made of stainless steel plates. The kinds of tubes for the measurement are 5 annular types and helical types. The pressure drop & the velocity of the flow are obtained by micromanometer & digital pressure sensor, supplying dry air at several steps. Then the pressure drop is calculated for each tube, using the obtained data. The result shows that the pressure drop is strongly influenced by the viscous dissipation of kinetic energy due to the circulation of flows, rather than a viscous friction loss. The pressure drop increased consistently as the Reynolds number increases.