Masato Hirota MRI Measurements of Fibre- Suspension Flow in a Sudden Contraction/Expansion FP1005 & SIG43 Workshop NTNU, Trondheim October 2012

2/17 Outline 1.Introduction 2.Experimental Setup 3.Results 4.Conclusions and future works

3/17 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

4/17 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

5/17 Target and objective of the study Target Objective Fibre-suspension flow in a pipe through a sudden contraction and expansion Obtaining velocity profiles using MRI and determining the effect of the pulp fibre

6/17 Experimental Setup

7/17 Experimental setup Magnet Contraction Pump Flow meter Ｐ Ｍ

8/17 Experimental conditions O x r 175 [mm] 130 [mm] 100 [mm] D d Diameter of the pipe : D =45 [mm] Diameter of the contraction : d = 23 [mm] Bulk velocity : U = 78.6 [mm / s] Flow U Bulk Reynolds number : Fraction of fibre (Softwood) : 0, 0.5, 1.0 wt %

9/17 Results

10/17 Vertical direction g 1.0% pulp 0% pulp 0.5% pulp Velocity profile at upstream (x=-130) x O Flow Horizontal direction Plug flow Turbulent flow Laminar flow –Paper pulp stabilizes the flow and forms plug flow –Paper pulp makes sedimentation

11/17 Velocity profile around contraction (x=-105, -70, Horizontal) x O 70 Flow x=-105x= % pulp 0% pulp 0.5% pulp 1.0% pulp 0% pulp 0.5% pulp

12/17 30 Velocity profile around expansion (x=-30, 30, Horizontal) x O 30 Flow x=-30x=30 1.0% pulp 0% pulp 0.5% pulp 1.0% pulp 0% pulp 0.5% pulp

13/17 1.0% pulp 0% pulp 0.5% pulp g 1.0% pulp 0% pulp 0.5% pulp Effect of sedimentation 30 x O 130 Flow x=30 (Horizontal) x=-130 (Vertical) Upstream velocity profile might affect downstream Flow of 0.5% suspension has remarkable velocity profile

14/17 Velocity profile at downstream (x=120, Horizontal) x=120 x O 120 Flow 1.0% pulp 0% pulp 0.5% pulp

15/17 Effect of turbulence MRI measurement in unsteady flow is still challenging x O 120 Flow 0% pulp (Turbulent) Acquired signal at x= % pulp (Laminar) Turbulence attenuates signal intensity

16/17 Conclusions and Future works

17/17 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

18/17 Thank you for your attention