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  • 1.
    Xie, Qiancheng
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Yang, James
    Vattenfall AB, R&D Hydraulic Laboratory, 81426 Älvkarleby, Sweden; Department of Civil and Architectural Engineering, Royal Institute of Technology, 10044 Stockholm, Sweden.
    Lundström, Staffan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Chen, Jieren
    College of Water Conservancy and Hydropower Engineering, Hohai University, 210098 Nanjing, China.
    Hybrid Modeling for Solutions of Sediment Deposition in a Low-Land Reservoir with Multigate Sluice Structure2022Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 12, nr 18, artikkel-id 9144Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    At the multigate sluice structure on a fluvial river, undesired sediment deposition affects the normal operation of the reservoir in question. Physical and numerical models are hybridized to help explore flow and sedimentation patterns. Field and laboratory investigations show that the deposition is attributable to the formation of large recirculation zones at low and medium discharges. As a potential countermeasure, an array of guide vanes is recommended to cope with the concern. Their attack angle with the flow is a dominant parameter that needs to be evaluated. Tests in the fixed-bed model demonstrate that the vanes bend the reservoir flow towards the sluice and suppress the circulation zones along both banks. The favorable range of attack angle is 15–20°. With the examination of sedimentation of both bed and suspended loads, the numerical modeling indicates that the sediment-removal efficiency increases with an increase in attack angle. By weighing the flushing efficiency and the risk of local scouring at the vanes, the 15° vane layout is recommended. This study is expected to provide a reference for guide-vane design in similar situations.

    Fulltekst (pdf)
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  • 2.
    Yang, James
    et al.
    Vattenfall AB, Research & Development (R & D), Hydraulic Laboratory, Älvkarleby, Sweden;Division of Resources, Energy & Infrastructure, Royal Institute of Technology, Stockholm, Sweden.
    Andreasson, Patrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik. Vattenfall AB, Research & Development (R & D), Hydraulic Laboratory, Älvkarleby, Sweden.
    Teng, Penghua
    Division of Resources, Energy & Infrastructure, Royal Institute of Technology, Stockholm, Sweden.
    Xie, Qiancheng
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    The Past and Present of Discharge Capacity Modeling for Spillways: A Swedish Perspective2019Inngår i: Fluids, E-ISSN 2311-5521, Vol. 4, nr 10, artikkel-id 4010010Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Most of the hydropower dams in Sweden were built before 1980. The present dam-safety guidelines have resulted in higher design floods than their spillway discharge capacity and the need for structural upgrades. This has led to renewed laboratory model tests. For some dams, even computational fluid dynamics (CFD) simulations are performed. This provides the possibility to compare the spillway discharge data between the model tests performed a few decades apart. The paper presents the hydropower development, the needs for the ongoing dam rehabilitations and the history of physical hydraulic modeling in Sweden. More than 20 spillways, both surface and bottom types, are analyzed to evaluate their discharge modeling accuracy. The past and present model tests are compared with each other and with the CFD results if available. Discrepancies do exist in the discharges between the model tests made a few decades apart. The differences fall within the range −8.3%–+11.2%. The reasons for the discrepancies are sought from several aspects. The primary source of the errors is seemingly the model construction quality and flow measurement method. The machine milling technique and 3D printing reduce the source of construction errors and improve the model quality. Results of the CFD simulations differ, at the maximum, by 3.8% from the physical tests. They are conducted without knowledge of the physical model results in advance. Following the best practice guidelines, CFD should generate results of decent accuracy for discharge prediction.

    Fulltekst (pdf)
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  • 3.
    Yang, James
    et al.
    Vattenfall, R&D Hydraulic Laboratory, Älvkarleby, Sweden; Civil and Architectural Engineering, Royal Institute of Technology, Stockholm, Sweden .
    Teng, Penghua
    Civil and Architectural Engineering, Royal Institute of Technology, Stockholm, Sweden .
    Xie, Qiancheng
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Li, Shicheng
    Civil and Architectural Engineering, Royal Institute of Technology, Stockholm, Sweden .
    Understanding Water Flows and Air Venting Features of Spillway: a Case Study2020Inngår i: Water, E-ISSN 2073-4441, Vol. 12, nr 8, artikkel-id 2106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For safe spillway discharge of floods, attention is paid to the water flow. The resulting air flow inside the facility, an issue of personnel security, is sometimes disregarded. The spillway in question comprises two surface gates and two bottom outlet gates lying right below. Air passages to the outlet gates include an original gallery and a recently constructed vertical shaft. To understand water-air flow behavior, 3D CFD modelling is performed in combination with the physical model tests. The simulations are made with fully opened radial gates and at the full pool water level (FPWL). The results show that the operation of only the bottom outlets leads to an air supply amounting to ~57 m3/s, with the air flow rates 35 and 22 m3/s to the left and right outlets. The air supply to the right outlet comes from both the shaft and the gallery. The averaged air velocity in the shaft and the gallery are approximately 5 and 7 m/s. If only the surface gates are fully open, the water jet impinges upon the canal bottom, which encloses the air space leading to the bottom outlets; the air flow rate fluctuates about zero. If all the four gates are open, the total air demand is limited to ~10 m3/s, which is mainly attributable to the shear action of the meeting jets downstream. The air demand differs significantly among the flow cases. It is not the simultaneous discharge of all openings that results in the largest air demand. The flood release from only the two outlets is the most critical situation for the operation of the facility. The findings should provide reference for spillways with the same or similar layout

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