• The KSFM Journal of Fluid Machinery
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• v.4 no.2 s.11
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• pp.35-43
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• 2001

The flow characteristics passing a multi-point Pitot tube flow-meter of diamond shape and the characteristics of flow coefficients of the flow-meter are experimentally studied by varying combination of upstream rectangular dual elbows. The results provide the flow coefficients, which show good stability and reliability within the Reynolds number range coveted here in this study, and which can be used to measure flow-rates in practice. The variation of dual elbows upstream can change the velocity field so much that the flow pattern might thwart the precise flow measurement using the multi-point Pitot tube. The strongest swirl is detected in the case of $90^{\circ}$ dual elbow combination of all. In addition, it is observed that flow separation remains unchanged and occurs at the same point irrespective of various upstream dual elbow combinations.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.248-251
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• 2006

Multi-physics problem is considered for the Pitot tube located in uniform freon gas flow with high Mach number and the 3D numerical results of temperature on Pitot tube is given. The model is created by using structural module of ANSYS, the grids are obtained by ICEM, and the problem is solved and the data post-processing is done by CFX.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.2042-2052
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• 2003

An experimental study was performed to investigate heat transfer characteristics of turbulent swirling flow in an axisymmetric annuli. The static pressure, the local flow temperature, and the wall temperature with decaying swirl were measured by using tangential inlet conditions and the friction factor and the local Nusselt number were calculated for Re=30000∼70000. The local Nusselt number was compared with that obtained from the Dittus-Boelter equation with swirl and without swirl. The results showed that the swirl enhances the heat transfer at the inlet and the outlet of the test tube.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.190-195
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• 2001

Flow patterns are very complex and interactive between cylinders. The patterns are turbulent and non-linear caused by various factors. In this paper, flow patterns and pressure gradient around vertical cylinders were investigated by experiment. Changing gaps between cylinders the flow patterns are measured at a fixed coming velocity. Flow patterns showed very complex and closely related to the coming velocity and cylinder space. The pressure gradient around the flow field is observed by twelve hole pitot tubes and manometer. The experiment has been conducted in circulating water channel with PIV system. That can visualize flow patterns. The laser beam was used to reflect the image from particles and recorded by CCD camera. The cylinders were spaced from ID to 5D with 0.5m/sec of incoming flow velocity. The experimental results using pitot tube showed in good agreement with results of precious by others study. The results can be applied in the understanding and design of multiple pile array structures.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.160-165
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• 2004

MPA (Multi-Point Averaging) flow element is a new type of differential pressure (DP) flow-sensing device that was developed by Seojin Instech to improve the operating characteristics of the conventional Averaging Pilot Tube (APT) flow elements. Operating characteristics of a flowmeter in general can be defined in terms of measurement accuracy and range. Improvement of accuracy and expanding the range of flow measurement were the two main objectives of the development. To achieve these dual objectives several upstream and downstream pressure-sensing holes were placed in MPA flow element. During the course of the development it was found that certain arrangements of the pressure-sensing holes improved measurement accuracy but did not expand operating flow range of Averaging Pilot Tubes. Development tests were performed with water between Reynolds number of 50,000 and 1,000,000 in the four-inch test line at the Alden Research Laboratory, U.S.A. Purpose of this paper is to present the relationship between the various locations of the pressure-sensing holes and the performance characteristics of MPA flow element. Furthermore, the operating characteristics of the best performing MPA are compared with those of typical orifice and APT.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.8
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• pp.1061-1070
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• 2003

A triple flame in a mixing layer was studied experimentally with concentration gradient and mean velocity by using a multi-slot burner, which can stabilize the lift-off flame. Flame stabilization condition, lift-off heights, and some other characteristics were examined for methane and propane flame within a range of very low concentration gradient. Pitot-tube and LDV(Laser Doppler Velocimetry) were used for velocity. Mass spectroscopy and Rayleigh scattering signal were used for concentration gradients. Thermo-couples and SiC TFP(Thin Filament Pyrometer) were used for temperature. It was found that minimum values of the lift-off heights exist at a certain concentration gradient for constant mean velocity and this means that the propagation velocity has a maximum value. The scales of flame to the burner nozzle and intensity variation of the diffusion flame were suspected as the cause.