180 likes | 200 Views
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.
E N D
Masato Hirota MRI Measurements of Fibre-Suspension Flow in a SuddenContraction/Expansion FP1005 & SIG43 Workshop NTNU, Trondheim 24-26 October 2012
Outline • Introduction • Experimental Setup • Results • Conclusions and future works
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
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
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
Experimental setup Contraction Magnet Pump Flow meter M P
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 %
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
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
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
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
Velocity profile at downstream (x=120, Horizontal) x Flow O 120 x=120 0% pulp 0.5% pulp 1.0% pulp
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
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