The thick red line gives the result of equation (10.1-1) using the DHLLDV Framework for heterogeneous and homogeneous transport. For the ELM curve it is assumed that the water density can be replaced by the mixture density and there is no further solids effect. The pipeline resistance curve for pure liquid (water, the blue ascending line) and the ELM curve (the brown ascending line). The 5 th term represents the total elevation pressure loss, from suction mouth to discharge.įigure 10.1-2: A pump pressure and pipeline resistance graph, D p =0.85 m, d=0.3 mm, L=10 km.įigure 10.1-2 shows two pump curves, one for pure liquid (water, the blue descending line) and one for a mixture density ρ mof about 1.4 tons/m3 (the brown descending line).The 4 th term represents the pressure losses due to many fittings, telescopes and so on.The 3 rd term is the solids effect based on the DHLLDV Framework.For large diameter pipes and high line speeds the Darcy Weisbach friction factor is close to λ l =0.01. The Darcy-Weisbach friction factor can be determined from the Moody diagram. The 2 nd term is the so called Darcy-Weisbach term for straight pipeline resistance of pure liquid (water in this case).For the total pressure loss this is negligible, but for the calculation of possible cavitation at the inlet of the first pump it is. Basically this can be determined from the Bernouilli equation. So the mixture has to be accelerated from zero velocity to the line speed, resulting in some pressure loss.

Outside the pipe the mixture is assumed not to have a velocity, but inside the pipe it has the line speed.

The 1 st term represents the acceleration losses.The pressure loss equation consists of 5 terms: However for this example it does not make a lot of difference. The suction pipe is usually a bit larger than the discharge pipe. In this example it is assumed that the suction pipe and the discharge pipe have the same diameter.

What is the suction lift dredge