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Study on the Detailed Structure of Choking Flow in a Straight Channel
Vincent Lijo,권준경(Joon Kyeong Kwon),김희동(Heuy Dong Kim) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5
As per some recent experimental data carried out in a straight pipe, the flow Mach number exceeds unity at the exit of pipe with initially subsonic flow conditions. This conflicts the Fanno flow theory that has long been applied to the one-dimensional gas dynamics area. At present, it is not clear whether this comes from experimental errors or any other reasonings which were not yet disclosed. In order to clarify this, computational analysis has been performed to explore detailed mechanism of the flow choking at the vicinity of pipe exit. Also a detailed theoretical analysis of sonic gas flow in pipeline under adiabatic condition has been performed and compared with CFD results.
강민성(Min Sung Kang),권준경(Joon Kyeong Kwon),김희동(Heuy Dong Kim),Toshiaki Setoguchi 한국추진공학회 2009 한국추진공학회지 Vol.13 No.3
A computational study has been performed out to evaluate the effect of a vertical porous barrier on the pressure oscillations in a supersonic cavity. The porous barriers with different perforations were vertically installed into a rectangular cavity at Mach numbers 1.50, 1.83 and 2.50. TVD finite difference MUSCL scheme was employed to solve the two-dimensional, unsteady, compressible Navier-Stokes equations. The present vertical porous barrier considerably altered the characteristics of the time-dependent shear layers that occur at the upstream edge of cavity and remarkably reduced the pressure oscillations inside the supersonic cavity. The present results showed that the effectiveness of passive control using the present porous vertical barrier is dependent on Mach number and the perforation of the porous barrier.
Abhilash Suryan,Dong-Sun Kim(김동선),Hae-Dong Lee(이해동),Joon-Kyeong Kwon(권준경),Heuy-Dong Kim(김희동) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
The ever increasing demand for power and the shortages encountered during summer calls for the implementation of strategies for power saving in industry. Inlet fogging of gas turbine engines is quite popular due to the ease of installation and the relatively low initial cost compared to other inlet cooling methods. In the present investigation, a detailed analysis is carried out on the basis of coincident wet bulb and dry bulb temperature data of a compressed air plant from April to October, 2007 to determine the evaporative cooling potential for the period. The power gain that can be obtained by employing inlet fogging of the air compressors is analyzed based on the real climatic data at several sites in Korea. An experimental set-up was constructed and tests were carried out with the standard impaction pin nozzle. The experimental results were found to match with the theoretical calculations.
강민성(Min-Sung Kang),신춘식(Choon-Sik Shin),권준경(Joon-Kyeong Kwon),김희동(Heuy-Dong Kim) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
The subcavity passive control technique is used in present study. Cavity-induced pressure oscillation has been investigated numerically for a supersonic three-dimensional flow over rectangular cavities at Mach number 1.83 at the cavity entrance. Time dependent supersonic turbulent flow over cavity were examined by using the three-dimensional, mass-averaged Navier-Stokes equations based on a finite volume scheme and large eddy simulation. The results showed that the resultant amount of attenuation of cavity-induced pressure oscillations was dependent on the length and thickness of the flat plate.