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10.6: Conclusions and Discussion

  • Page ID
    32677
  • The theory described in this book can be applied to a real life pump/pipeline system with the equations derived in this chapter. In these equations the relative excess hydraulic gradient Erhg has to be determined with the DHLLDV Framework. This can be both for a constant spatial volumetric concentration and/or a constant delivered volumetric concentration.

    By defining 5 different flow regimes and using these flow regimes to construct the relative excess hydraulic gradient curve, a good representation of the physics of two pase flow is achieved. Most other models only consider one flow regime.

    The behaviour of a multi pump/pipeline system is hard to understand. An infinite number of system configurations and soil conditions exist. Systems are usually configured, based on steady state calculations, while the dynamic behaviour is ignored. Combining the steady state approach for pipeline resistance with the dynamic behaviour of pumps, pump drives and the second law of Newton, the dynamic behaviour can be simulated.

    Multi pump/pipeline systems can be configured in an infinite number of configurations. Phenomena that occur in one configuration do not have to occur in other configurations. So the configuration to carry out simulations to examine certain phenomena has to be chosen carefully. The examples show, that moving from one working point to the next working point, does not occur instantaneously, but with a time delay, where the time delay depends on the phenomena.

    The simulation model used is very well suitable for fully suspended load, but has a deficiency for two phase flow. The main shortcoming is the fact that suspended load and bed load move through the system at two different velocities, not being equal to the average line speed.

    A second shortcoming is the lack of availability of a good model for the vertical diffusion between the suspended load and the bed load. This will be subject for further research.

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