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

More documents

Recommendations

Info

3.3 Solving scheme The governing equation can be solved either for a given head or a given total discharge. For both a first estimate is used as a starting value and further iterations lead to the final value. 3.3.1 Solving for total head At the first port/riser on the seaward side (i = 1) an initial discharge q 1 is estimated, for example q 1 = Q/N with Q = total discharge and N = total number of risers. Equation (19) then allows to calculate the first internal pressure of the diffuser p d,1 . The further discharges q 2 until q N are calculated using equation (20). A final application of equation (18) allows to calculate p d,N+1 , the necessary pressure at the headworks to drive the system. The total head H t can be calculated by H t = p d,N+1 /γ effluent if the water level elevation of a gravity driven system has to be defined. The calculated total discharge is Q c =∑ N q k k = 1 . The difference to the planned total discharge is diffc = Q - Q c . If necessary (i.e. for diff c > Q/10000) CorHyd performes further iterations with modified estimates q 1,c . To achieve faster convergence the following algorithm (eq. (22)) has been implemented to calculate q 1,c : q 1,1 = Q/N; q 1,2 = q Q 1,1 ; Q q1,c = q 1,c-2 diff c-1 -q diff 1,c-1 c−2 for (c>2) (22) 1 diff 1 − diff 2 The iteration stops if the difference between the given total discharge and the calculated total discharge is less than 10 -5 Q. The results are individual port/riser discharges and velocities in all pipe sections along the diffuser and a total head. These can be displayed or printed with further output options. c− c− 3.3.2 Solving for total flow At the first port/riser on the seaward side (i = 1) an initial internal pressure p d,1 is estimated, for example p d,1 = H t γ e /N + p a,1 + γ e (z jet,i - z d,i ) with H t = total head at headworks. Equation (19) then allows to calculate the first discharge q 1 . The further discharges q 2 until q N are calculated using equation (20). A final application of equation (18) allows to calculate p d,N+1 , the necessary pressure at the headworks to drive the system. The total head H t can be calculated by H t = p d,N+1 /γ e if the water level of a gravity driven system has to be defined. The N q k k = 1 calculated total discharge is Q c =∑ . The difference to the planned total head is diffc = H t - H tc . If necessary (i.e. for diff c > H t /10000) CorHyd performes further iterations with modified estimates p d,1,c . To achieve faster convergence the following algorithm has been implemented to calculate p d,1,c : p d,1,1 = H t γ e /N+p a,1 +γ e (z jet,i -z d,i ); p d,1,2 = p H t d,1,1 ; H pd,1,c = p d,1,c-2 diff c-1 -p diff d,1,c-1 c−2 t1 diffc− 1 − diffc− 2 for (c>2) (23) Institut für Hydromechanik, Universität Karlsruhe 31
The iteration stops if the difference between the given total head and the calculated total head is less than 10 -5 H t . The results are individual port/riser discharges and velocities in all pipe sections along the diffuser and a total discharge. These can be displayed or printed with further output options. Institut für Hydromechanik, Universität Karlsruhe 32
Page 1 and 2: Universität Karlsruhe Institut fü
Page 3 and 4: Acknowledgments The authors like to
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: elevation difference between diffus
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
Page 55 and 56: Table 5: Sensitivity of involved pa
Page 57 and 58: Fig. 24: Side view and cross sectio
Page 59 and 60: Fig. 27: Flow characteristics for d
Page 61 and 62: under different flow conditions. Th
Page 63 and 64: Fig. 32: Side view and cross sectio
Page 65 and 66: Fig. 34: Flow characteristics for:
Page 71 and 72: Table 6: Comparison of construction
Page 73 and 74: seaward end, which can be prevented
Page 75 and 76: Especially for this long diffuser a
Page 77 and 78: Jirka, G.H., Doneker, R.L. and Hint
Page 79 and 80: 10 Annex 10.1 Local loss formulatio

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?