Eng. Adriana Bonilla Riaño, MsC.

Advisor: Dr. Antonio Bannwart

Co- advisor: Dr. Oscar M. H. Rodriguez

São Carlos, June 27th1

Some Activities: 2014-1S

• Qualifying exam

• Graduate teaching assistant: Eletrotécnica

• Calibration experiments

• High-speed-camera experiments and image processing

• WMS data processing

2

Planar sensor

3

• It is an array of transmitters (Tx) and receivers (Rx) on an insulating surface

• A voltage signal is applied to the Tx and current flows to the Rx

• The current depends on the thickness of the liquid film covering both electrodes

Tx

Rx

PCB (Insulating Surface)

Electric field lines

Water Film Thickness

E

Planar sensor calibration

4

4 3 2

1 2 3 4 5m m m ma c a c a c a c a

: the conductance/capacitance

: the film thickness

• The relationship between current and film thickness is non-linear

• is higher near to the sensor and decreases with the distance

mc

0 200 400 600 800 10000

0.2

0.4

0.6

0.8

1

Film Thickness [m]

Dim

en

sio

nle

ss C

urr

en

t [-

]

Film Thickness [µm]

Dim

ensi

on

less

cu

rren

t [-

]

• The calibration values are fitted with a fourth order polynomial by each pair Tx-Rx

E

Capacitive experimentsObjective: Test the selected geometry in a calibration experiment with the capacitance system

• At the NETeF (USP)

5

• Sensor of 26 x 32 electrodes

• Spatial resolution: 2mm x 2mm

• Temporal resolution: 100 fps

• Uncertainty of thecapacitive system: 3%

0 100 200 300 400 500 600 700 800 900 100010

20

30

40

50

60

70

80

Film Thickness [m]

Rela

tive P

erm

ittivity[-

]

Calibration data

4th degree

Film Thickness [µm]

Rel

ativ

e p

erm

itti

vity

[-]

High-speed-camera experimentsObjective: Assessing the possibility of measuring the water film in oil-water dispersed flow in pipes using a camera

6

• Horizontal acrylic pipe (26mm i.d. and 12m length), NETeF

• 12 experiments on dispersed flow

Challenges

• Correcting the optical distortions caused by the curved surface near the pipe wall. An acrylic box machined as an independent piece

• The illumination system because the frame rate

Re 100000m

High-speed-camera experiments

7

Square pattern for calibration with squares of 0.2mm by 0.2mm

Uws=2.5 m/s, Uos=1.2 m/s Uws=2.5 m/s, Uos=1.5 m/s Uws=2.0, Uos=1.1 m/s

• Camera: i-speed 3 Olympus

• Experiments at 5000fps

Automatic processing algorithm for film thickness estimation from images

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Image Processing

(a) Original image (b) After pre-processing

(c) Segmented Image (d) Average water film

thickness

Im

1

Np

FNp

Pipe walls

Pipe walls

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Segmented image by morphology

cmeans

Segmented image by conected regions

Global Thresholding - Iterative Method Segmented image by otsu with fixed level

Segmented Image by Active Countours

Image Processing

Original Image

Original frame

kmeans

Experiment 1: Uws=3 m/s, Uos=1.2 m/s

Thres-holding

Characteristics extraction and classification

Further work

Electronics implementations to reach a temporal resolution of at lest 5000 frames per second

Installation of the planar capacitive system and the visualization system in the test line (Vertical pipe line, 50.8mm i.d., 12m length)

Acquisition of a new oil-water dispersed flow data

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• NETeF

• Vertical Line: I.D. = 50.8 mm

• Glass pipe

Data treatment and analysis

o Water film characterization:

Shape, amplitude and wavelength of the pseudo interfacial wave

o Analysis on time domain and frequency domain

o Development of techniques for visualizing the data

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Further work

Presented papers1. A.B. Riaño, A.C. Bannwart, H.M. Prasser, J. Dupont and O.M.H.

Rodriguez, “A High Spatial and Temporal Resolution FilmThickness Sensor in Oil - Water Flows,” in 2014 IEEE InternationalInstrumentation and Measurement Technology Conference(I2MTC), Montevideo, May 12-15, Uruguay, 2014.

Submitted papers

1. A.B. Riaño, A.C. Bannwart, and O.M.H. Rodriguez, “ Film thickness measurements in oil-water pipe flow”, submitted for publication, 2014.

2. I.H. Rodriguez, H.F.V. Peña, A.B. Riaño, O.M.H. Rodriguez, “Capacitive Wire-mesh Sensor Measurements in Oil-water Flow”, in 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Orlando, June 14-16, USA, 2014.

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Acknowledgments

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Thank you!