Browsing by Author "Yuan, Mingshun"

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    Data Analysis and Numerical Modeling of Flow in the 1:14 Scale LCC Model
    (St. Anthony Falls Hydraulic Laboratory, 1989-06) Song, Charles C. S.; Yuan, Mingshun; Wang, Qun; He, Jianming
    A 1:14 scale model of the Large Oavitation Ohannel (LOO) was built and tested by Voith Hydro, Inc. [l]. The velocity profiles on the central plane of symmetry was surveyed using Pitot tubes at stations P1 to P7 as shown in Fig. 1. Later, additional measurements were made with LVD at stations Ll to L4 [2]. These measurements indicated the existence of unusually thick boundary layers on the top wall at the test section and poor flow quality in the diffuser when the honeycomb for turbulence management was present. Some improvements on mean velocity profiles were found possible by either completely or partially removing the honeycomb.
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    Extended Phase A-2, Large Cavitation Channel, Davld Taylor Naval Ship Research and Development Center
    (St. Anthony Falls Laboratory, 1984-08) Arndt, Roger E. A.; Song, Charles C. S.; Silberman, Edward; Killen, John M.; Wetzel, Joseph M.; Yuan, Mingshun
    It was suggested that a mild contraction located immediately upstream of the pump may improve the quality of flow which is expected to be quite nonuniform coming from the diffuser and the first and second elbow. To investigate the effect of the contraction ratio, the AROl computer model previously used in the Phase A-2 studies for the Large Cavitation Channel (LCC) main contraction design was applied to the pump contraction. As shown in Fig. 1, the contraction is assumed to be 5.563 m long and of circular cross section. Area contraction ratios of 0, 10, 20 and 30 percent were used. There is a fixed shaft of constant diameter along the centerline of the contraction. Two different shaft diameters, 0.508 m and · 1.016 m, were used based on information available at the time the study was conducted~ Initially, a fifth order polynomial was used for the contraction profile. The profile was later changed to a straight line because the contraction is so mild that the flow is not significantly affected by the boundary shape. Due to symmetry about the vertical plane, only half of the flow region was modeled. Different types of nonuniform inflow velocity profiles were studied. A total of 46 modeling runs covering various geometrical and flow conditions as well as different modeling parameters were made.
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    Hydrodynamic Analysis of the SSL Flow Facility
    (St. Anthony Falls Hydraulic Laboratory, 1987-03) Song, Charles C. S.; Yuan, Mingshun; Wetzel, Joseph M.
    A preliminary concept for a gravity flow test facility was evaluated using mathematical modeling techniques. Complete specifications for the hydrodynamic performance were not available. In the absence of these values, parametric studies were carried out to determine the sensitivity of flow quality indicators to dimensional changes. The target flow conditions in a circular test section with a 4 sq ft area were a 90 second test run at a constant velocity of 60 fps.