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Modeling the pressure drop in pipelines transporting highly vicous non-newtonian sludge

Woord, H. ter (2018) Modeling the pressure drop in pipelines transporting highly vicous non-newtonian sludge.

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Abstract:In Wastewater Treatment Plants, different types of sludge are produced, processed and treated. Implementation of new processes has caused increase in the dry solids content of the sludge, which has an effect on the flow behaviour (rheology) of the sludge. This has led to difficulty predicting the pressure drop in pipelines, thus a new model is sought. From literature, it is clear that sludge is a non-Newtonian fluid, with or without yield stress. Pipe flow calculations and pressure drop calculations are worked out for different non-Newtonian fluid models and an overview of current software for hydraulic calculations is given. Experimental research has been conducted at TDH Venlo in Venlo, where the pressure drop of two types of sludge was measured at varying flow rate and rheology was determined using a viscometer. For digested sludge of approx. 7% dry solids content, a power law model was found to describe the rheology best. Validation of the rheology with the pressure drop measurement was unsuccessful. For mechanically thickened secondary sludge of 11% dry solids content, the viscometer was found not suitable for determining the rheology, but a yield stress was clearly present. In conclusion, the experimental methods used did not provide results which are useful for modeling the pressure drop in pipelines where sludge is pumped. It is recommended that more research is done in order to obtain validated sludge models. Suggestions are done for methodology with which to reach this goal. Most important is determining whether a yield stress is present, determining the value of the yield stress and implementing calculations for yield stress fluid into the existing model.
Item Type:Internship Report (Master)
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Mechanical Engineering MSc (60439)
Keywords:Wastewater Treatment, Non-Newtonian fluid, Non-Newtonian Sludge, Pipe Flow
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