UNSTEADY FLOW IN INSTALLATIONS WITH POLYMERIC ADDITIONAL PIPE

The authors of this technical paper present the results of a theoretical and experimental investigation on the reduction of unsteady flow oscillations by using additional pipes of high-density polyethylene (HDPE) inserted at the upstream end of the pipeline in a pumping installation. Generally, the experiments show a reduction of the oscillations with respect to the case without the additional pipe. A higher reduction of oscillations is observed for larger volumes of the device, while oscillations tend to be amplified for very small volumes. Experimental data are used to evaluate the mechanical parameters of the pipe material using a numerical model based on the method of characteristics. The additional pipe is treated as a lumped parameter system. A linear elastic model and a Kelvin-Voigt viscoelastic model are used to describe the mechanical behavior of the HDPE. The numerical tests indicate that the viscoelastic model better describes the general phenomenon, but the elastic model sufficiently estimates the maximum and minimum oscillations. An analytical solution is presented for frictionless pipelines with the additional pipe considered as elastic. The case of pipelines with friction is explained in graphs that report the results of numerical integrations and allow the design of the device.

Language

  • English

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Filing Info

  • Accession Number: 00712812
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Nov 1 1995 12:00AM