user's manual for corhyd: an internal diffuser hydraulics model - IfH

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Version 1.0, June 2005 USER'S MANUAL FOR CORHYD: AN INTERNAL DIFFUSER HYDRAULICS MODEL by Tobias Bleninger, Gerhard H. Jirka Institute for Hydromechanics, University Karlsruhe Kaiserstr. 12, 76128 Karlsruhe, Germany, bleninger@ifh.uka.de http://www.cormix.de/corhyd.htm Abstract Submerged multiport diffusers for waste water outfalls are designed often, considering steady flow conditions for far future scenarios. Design aims for lower costs for material use and pumping energy and the minimization of environmental impacts. Inadequate attention on the internal diffuser hydraulics also for off design conditions thereby often result in hydraulic problems like partial blockage, high head losses, uneven flow distribution, salt water intrusion and poor dilution causing higher energy demands and stronger environmental impacts. The CorHyd computer program has been developed for the calculation of velocities, pressures, head losses and flow rates inside the diffuser pipe and, especially, at the diffuser port orifices to analyze and optimize diffuser design alternatives as well as existing diffuser configurations for different and varying discharge and ambient conditions. The calculation is based on the application of the steady continuity and work-energy equations between ambient fluid at the discharge points and the effluent inside the diffuser pipe. Emphasis was given to the implementation of all occurring losses especially if high risers, duckbill valves, multiple ports and more complex discharge configurations are applied. Detailed calculations for the internal manifold hydraulics in the outfall pipes show a strong sensitivity on the representation and formulation of local losses even for relatively simple riser/port configurations. An optimization methodology yields a homogeneous discharge distribution along the diffuser, minimization of the total head and prevention of sedimentation or ambient water intrusion in the diffuser under varying inflow and ambient conditions. The final design achieves lower costs for material use and operation as well as the minimization of environmental impacts and operational stability for off-design conditions. i
Acknowledgments The authors like to express their gratitude to the student assistants Martina Kurzke and Jan Müller who contributed to the coding of the present program. Thanks to Rob Doneker from Mixzon Inc. for his friendly and scientific help and the offer to include the program in CORMIX, the Cornell Mixing Zone Expert System. We furthermore appreciated the data support from TideFlex Technologies from RedValve Company and Elasto-Valve Rubber Products (EVR) company for developing loss formulations for duckbill valves. Institut für Hydromechanik, Universität Karlsruhe ii
Page 1: Universität Karlsruhe Institut fü
Page 5 and 6: 10.1 Local loss formulations: Divis
Page 7 and 8: 1 Introduction CorHyd is a computer
Page 9 and 10: Fig. 1: Outfall configuration showi
Page 11 and 12: where j 0 denotes the buoyancy flux
Page 13 and 14: 2.4 Manifold processes Pipe hydraul
Page 15 and 16: Fig. 8: Local port/riser branch los
Page 17 and 18: Table 2: Local loss formulations Ty
Page 19 and 20: Gradual contraction (Idelchik 1986)
Page 21 and 22: Where H denotes the headloss, V duc
Page 23 and 24: Table 3: Equivalent sand roughness
Page 25 and 26: Institut für Hydromechanik, Univer
Page 27 and 28: For a constant sea water level and
Page 29 and 30: (16) solved for r in (15) and assum
Page 31 and 32: 3.1.4 Automatic implementation of l
Page 33 and 34: elevation difference between diffus
Page 35 and 36: The iteration stops if the differen
Page 37 and 38: Table 4: CorHyd subroutines and the
Page 39 and 40: 4 Data Input Input can either be do
Page 41 and 42: (ρ 0,max > ρ 0 ). Further sensiti
Page 43 and 44: should allow for riser velocities,
Page 45 and 46: Fig. 19: First input sub-window for
Page 47 and 48: 10 7050.000 0.000 -2.500 11 7000.00
Page 49 and 50: Fig. 22: Graphical output: Energy a
Page 51 and 52: given dilution requirements and maj
Page 53 and 54:
6.3 Off design conditions It was co
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Table 5: Sensitivity of involved pa
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Fig. 24: Side view and cross sectio
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Fig. 27: Flow characteristics for d
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under different flow conditions. Th
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Fig. 32: Side view and cross sectio
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Fig. 34: Flow characteristics for:
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Page 69 and 70:
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Table 6: Comparison of construction
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seaward end, which can be prevented
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Especially for this long diffuser a
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Jirka, G.H., Doneker, R.L. and Hint
Page 79 and 80:
10 Annex 10.1 Local loss formulatio
Page 81 and 82:
Institut für Hydromechanik, Univer
Page 83 and 84:
Institut für Hydromechanik, Univer
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user's manual for corhyd: an internal diffuser hydraulics model - IfH

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