Relating Slurry Friction with Erosion Rate using a Toroid Wear Tester (TWT)

• Author / Creator

  Zhang, Lisheng

• In the mining industry, high wear rates in slurry pipelines can lead to premature/unplanned failure, causing operation outages and environmental incidents. Laboratory-scale wear studies and physics-based modelling are required to predict pipe wear. Recent studies have revealed a strong relationship between local shear stress and wear rate; so, for heterogeneous (settling) slurries, evaluation of the Coulombic (contact load) friction is a promising predictor of wear at the pipe invert. Since studies of wear in pipelines are expensive and time-consuming, this investigation focuses on Coulombic-friction-based wear prediction for slurry flows in a Toroid Wear Tester (TWT). The TWT has been found to be a promising apparatus in the study of contact-load-dominated wear.
  In this study, a torque sensor system was installed and used to measure the applied torque. Commissioning tests were performed, which indicated that the torque sensor could generate a consistent torque signal. The applied torque was measured for a wide range of particle sizes (0.125 mm to 2 mm), solid volume concentrations (10% to 20%), and TWT rotational speeds (10 to 90 RPM). It has been shown that applied torque, solid volume concentration, and terminal settling velocity are correlated. Qualitative flow observations were made to better understand the sliding bed geometry and further to relate the measured torque values to the Coulombic friction component. Estimation of the torque value was performed using modified equations from the two-layer model. The agreement between estimated and measured torque values indicates the Coulombic friction component can be determined. Corresponding erosion wear tests were conducted, and relating the Coulombic friction component with wear rate was attempted at 30 RPM and 60 RPM. It is
  observed that the wear rate grows with increased Coulombic friction. Therefore, it is concluded that very few tests are required to predict erosion wear rates in TWT. If there is a bridge between TWT and pipe flow, pipe wear can also be predicted based on a very small number of tests. In
  order to developing the bridge, quantitative comparisons between TWT and pipe loop wear results must be obtained. Also, a broader range of conditions must be tested, including particle types, wheel speeds, sizes of wear wheel and coupon material to further verify the relationship between Coulombic friction and wear rates.

• Subjects / Keywords

  • Coulombic friction
  • Toroid Wear Tester
  • Erosion rate

• Graduation date

  Fall 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3TM72H16

• License

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