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

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testi-f16 image nr. 1

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Thank you for your attention!