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Masato Hirota

Masato Hirota. MRI Measurements of Fibre- Suspension Flow in a Sudden Contraction/Expansion. FP1005 & SIG43 Workshop NTNU, Trondheim 24-26 October 2012. Outline. Introduction Experimental Setup Results Conclusions and future works. Fibre-suspension flow.

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Masato Hirota

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  1. Masato Hirota MRI Measurements of Fibre-Suspension Flow in a SuddenContraction/Expansion FP1005 & SIG43 Workshop NTNU, Trondheim 24-26 October 2012

  2. Outline • Introduction • Experimental Setup • Results • Conclusions and future works

  3. Fibre-suspension flow Fluid motion in papermaking process affects quality of paper Clarifying and controlling the flow is consistent way to increase quality of paper Studying in practical condition is necessary Contraction and expansion of the flow Steady and unsteady flow

  4. Nuclear Magnetic Resonance Imaging (NMRI) for flow measurement Protons in fluid are traced Non-invasive flow measurement method Not adversely affected by optical opaqueness Local velocities of fluid are measured by phase encode imaging

  5. Target and objective of the study Target Fibre-suspension flow in a pipe through a sudden contraction and expansion Objective Obtaining velocity profiles using MRI and determining the effect of the pulp fibre

  6. Experimental Setup

  7. Experimental setup Contraction Magnet Pump Flow meter Ｍ Ｐ

  8. Experimental conditions r U x D d O Flow 100 [mm] 130 [mm] 175 [mm] Diameter of the pipe : D=45 [mm] Diameter of the contraction : d= 23 [mm] Bulk velocity : U = 78.6 [mm / s] Bulk Reynolds number : Fraction of fibre (Softwood) : 0, 0.5, 1.0 wt %

  9. Results

  10. Velocity profile at upstream (x=-130) x Flow O 100 130 Vertical direction Horizontal direction 0.5% pulp Laminar flow Turbulent flow 0% pulp g 1.0% pulp Plug flow • Paper pulp stabilizes the flow and forms plug flow • Paper pulp makes sedimentation

  11. Velocity profile around contraction (x=-105, -70, Horizontal) x Flow O 70 105 x=-105 x=-70 0.5% pulp 0% pulp 0% pulp 0.5% pulp 1.0% pulp 1.0% pulp

  12. Velocity profile around expansion (x=-30, 30, Horizontal) x Flow O 30 30 x=-30 x=30 1.0% pulp 0.5% pulp 1.0% pulp 0% pulp 0.5% pulp 0% pulp

  13. Effect of sedimentation x Flow O Flow of 0.5% suspension has remarkable velocity profile 30 130 x=-130 (Vertical) x=30 (Horizontal) 0.5% pulp 0.5% pulp 1.0% pulp 0% pulp g 1.0% pulp 0% pulp Upstream velocity profile might affect downstream

  14. Velocity profile at downstream (x=120, Horizontal) x Flow O 120 x=120 0% pulp 0.5% pulp 1.0% pulp

  15. Effect of turbulence x Flow O Turbulence attenuates signal intensity 120 Acquired signal at x=120 0% pulp (Turbulent) 1.0% pulp (Laminar) MRI measurement in unsteady flow is still challenging

  16. Conclusions and Future works

  17. Conclusions and future works MRI measurement of pulp suspension flow in a sudden contraction and expansion has been performed • Conclusions • Pulp in water behaves like increasing of viscosity before it forms plug flow • Sedimentation affects velocity profile • Future works • Improving MRI protocols • Coupling between horizontal and vertical direction

  18. Thank you for your attention

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