Calculation for Head Loss Between Manhole
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Transcript of Calculation for Head Loss Between Manhole
wtrprof.WATER PROFILE IN STORM SEWER PIPE FROM COLLECTION PIT TO SWOCALCULATION FOR HEAD LOSSNo.Pipe No.DIA.1200DIA.1800SIUSSIUS1Q (m3/s) or cfs1.88166.4274.346153.4782Length (m) or ft218.300716.207831.7002728.6752Hazen William Roughnesss-C1201201201203Diameter (m) or (in.)1.20047.2441.80070.8664Friction Loss, (m) or (ft)0.4181.4281.0433.5635Velocity (m/s) or (ft/s)1.6635.4571.7085.6036Velocity Head-V2/2g, (m) or (ft)0.1410.4630.1490.488Note :1.Friction Loss per 1000 m (for SI) :where :Q = the flow in m3/sD = Diameter of Pipe in mFriction Loss per 1000 ft (for US) :where :Q = the flow in cfs (ft3/s)D = Diameter of Pipe in in.and C = The Hazen-Williams value :for PVC = 140for concrete pipe = 1202.Velocity = Q / A (m/s for SI and ft/s for US)whereA = sectional area of pipe (m2 for SI and ft2 for US)3.Minor Head Loss associated with discharges are V^2 / 2g - (m for SI and ft for US)4.Minimum Head Loss associated with entrance losses area 0.2 * (V^2 / 2g ) - (m for SI and ft for US)5.Water surface profile came from Bernoulli's Equation that show the energy drop between water and pipe/manholes and show volume water still able to pass the pipe with velocity (Q/A) > 0.4 m/s.
Total Energy LineCollection Pit-1COB - 4SEL.99230EL.97600TOP. EL.99900EL.98700Entrance loss :0.2*V2/2g=0.2*0.141=30 mmEL.99230 - 30 mm = EL.99200Friction Loss = 418 mmEntrance loss for 3 manholes =3*0.2*V2/2g=3*0.2*0.141 =85 mmEL.99200 - 418 mm - 85 mm = EL.98697Velocity Head = 141 mmEL.98697 - 141 mm = EL.98556Entrance loss at manhole is :0.2*V2/2g=0.2*0.149 =30 mmEL.98556 - 30 mm = EL.98526Friction Loss = 1043 mm Entrance loss for 11 manholes =11*0.2*V2/2g=11*0.2*0.149 =328 mmEL.98526 - 1043 mm - 328mm = EL.97155TOP. EL.99900BOP. EL.96500TOP. EL.98530SWOPIPE DIA.1200PIPE DIA.1800218.3 M831.7 MHloss per 1000 = [ 146.43 * Q / ( C * D^2.63) ]^1.85Hloss per 1000 = [ Q / ( 0.006756 * C * D^2.63) ]^1.85