Pentti Saarenrinne13th Oct 2011
Experimental fluid dynamics at
Department of the Energy and Process Engineering,
Tampere University of Technology
Dept. of Energy and Process Engineering
Figures• Budget 3,6 M€ (1,7 +1,9 M€)
• 7 professors
• 30 researchers & research assistants
• 6 technicians
Research topics• Fluid Mechanics & Heat Transfer
(CFD & Experimental)
• Paper converting and packaging
• Refrigeration Technology
• Combustion & Power Plant Technology
The EFD group
The group is specialized in optical measurement techniques in fluid mechanics and their adaptation to multi-phase flows.
Other research topics include turbulence, fluid-structure interactions, flow control, and mixing.
The team:• Pentti Saarenrinne, Professor, D. Sc. (Tech)• Hannu Eloranta, D. Sc. (Tech.) moved to Pixact Ltd• Markus Honkanen, D. Sc. (Tech.)• Maria Putkiranta, M.Sc. (maternity leave)+ M.Sc. students
Measurement facilities
For single-phase flows• PIV (three systems, including
high-speed SPIV)
• LDA
For multi-phase flows• Direct imaging (high-speed &
others)
• PDA
The laboratory has several water circulation loops, mixing tanks…
Paper converting laboratory• Pilot plant (1 m width)
• Laboratory
Fiber suspension flows
Simultaneous PIV and DI in a dilute fiber suspension flow
Fiber suspension flows
Simultaneous PIV and DI in a dilute fiber suspension flow
Fiber orientation and flocculation measurements
Experiments are conducted…
The flow setup
Fiber orientation measurements
The effect of fiber consistency...
C=0.02%-w C=0.1%-w
C=0.5%-w
Fiber orientation measurements
The flocculation experiments
• Pine, 0.5%-w (mean length: 2.3mm, crowding factor: ~60)
• Two flow rates: 2.25 l/s (Uexit=5.0m/s) and 4.00 l/s (Uexit=8.5m/s)
• Two channels
Data collection
• Images of the fiber phase were collected with two back-lighting systems:
• Double-frame camera operating at 4 Hz
• High-speed camera operating at 1000-4000 Hz
Floc orientation
Mean floc size scale and aspect ratio
Bubble analysis with 3D orthogonal imaging
• Rising bubbles, frame rate 1000 1/s .
• Orthogonal projections of the flow was achieved with a mirror system.
• Automatic image analysis recognises bubbles, even when they are overlapping.
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Ink removal from recirculated pulp suspension
- Measurements in a flotation tank
- Submerged probe for the bubble size distribution in the inlet jet.
Image analysis
Air removal from fiber suspension in an open channel flow
• Submerged measurement device sinking in suspension .
•Bubble movement in a fiber suspension.•Blue broken lines are bubble path lines.
The strain distributions inside a year ring during sudden compression in a split-Hopkinson device
Objectives:• To develop an imaging and illumination method for the phenomena• The preparation of the wood samples to enable the measurement of the
deformation inside a year ring• Measurement were made at elevated temperatures in a closed split-
Hopkinson device at Mid-Sweden University (Sundsvall).
Results:• From the deformation images was computed strain maps. • The year rings of the sample are on the right hand side of the large
strain areas. • The deformation in the ”spring” wood is bigger
The strain distributions inside a year ring in sudden compression /2
With frame rate 50 000 1/s was imaged in one Compression a serie of 12 images.
A Laboratory Scale CFB
H x W x D: 3.0 x 0.4 x 0.015 m.
Cold model.
Fluidization velocities up to 4.0 m/s.
Sauter mean diameters: 442 μm or 255 μm.•Particle size distribution was measured with shadowgraphy:
High speed imaging at the bottom part of the model
Frame rate300Hz Red arrow, velocity upwards 5 m/s, Blue arrow same velocity downwards
x [mm]
y [m
m]
testi-f16 image nr. 1
0 10 20.1 30.1 40.1 50.2 60.2
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x [mm]
y [m
m]
testi image nr. 0
0 4.2 8.4 12.6 16.7 20.9 25.1
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Thank you for your attention!
