Experimental fluid dynamics at
Department of the Energy and Process
Engineering,
Tampere University of Technology
Pentti Saarenrinne
13th Oct 2011
Dept. of Energy and Process Engineering
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Budget 3,6 M€ (1,7 +1,9 M€)
7 professors
30 researchers & research
assistants
6 technicians
Research topics
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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 multiphase 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
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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)
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Two channels
Data collection
• Images of the fiber phase were collected with two backlighting 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
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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 splitHopkinson device at Mid-Sweden University (Sundsvall).
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.
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
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
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Thank you for your attention!