flow measurement based on two-dimensional flexural ... · flow measurement based on two-dimensional...

Centre for Industrial Ultrasonics Open Day

25th April 2018

CIU Centre for Industrial Ultrasonics www.ciu.ac.uk 1

Flow Measurement Based on Two-Dimensional

Flexural Ultrasonic Phased Arrays

Lei Kang1 , Andrew Feeney1, and Steve Dixon1&2

Department of Physics1

School of Engineering2

University of Warwick

2CIU Centre for Industrial Ultrasonics www.ciu.ac.uk

Contents

1 Background and motivation

2 Design and optimization

3 Fabrication of flexural ultrasonic arrays

4 Characterization of flexural ultrasonic arrays

5 Flow measurement tests

6 Summary and future research

3CIU Centre for Industrial Ultrasonics www.ciu.ac.uk

Ultrasonic transit-time flow measurement suffers from

beam drift effect which reduces the accuracy and range.

Phased Array technology:

• Adjusting sound beam electronically

and dynamically;

• Measuring through multiple paths

(direct path, reflected paths).

1 Background and Motivation

4CIU Centre for Industrial Ultrasonics www.ciu.ac.uk

1 Background and Motivation

Flexural Ultrasonic Transducers (unimorph, bimorph):

• Uses bending modes in a plate;

• Generates and receives ultrasound

efficiently in fluids;

• Low cost and low voltage supply.

Flexural Ultrasonic Phased Arrays:

• Combining the advantages of flexural

ultrasonic transducers and phased

array technology;

• A potentially economic and low voltage

solution for flow measurement with

higher accuracy and larger range.

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2 Design and Optimization

(0,0) mode (1,0) mode

3D Axisymmetric FE model

(0,0) mode: PZT/Mem=0.92

(1,0) mode: PZT/Mem=0.53

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3 Fabrication

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4 Characterization – impedance analyzer

Table 1: Centre frequency of elements of

a typical array (unit: kHz)

• Backplate not only enhances the

mechanical robustness of the array,

but also improves the performance of

the array in terms of its amplitude,

mode purity, mechanical crosstalk.

• Averaged -6 dB bandwidth: 1.5 kHz.

CIU Centre for Industrial Ultrasonics www.ciu.ac.uk

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8-cycle tone burst signal

transmitting simultaneously

8-cycle tone burst signal

transmitting with time delay

(30o beam steering mode)

Only one element is driven

(study of mechanical cross)

• Array elements vibrate in the (0,0) mode;

• No obvious debonding or weak bonding is observed;

• Crosstalk between neighbouring elements doesn’t severely affect performance.

4 Characterization – laser vibrometer

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5 Flow measurement tests

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5 Flow measurement tests

0 500 1000 1500 2000 2500

Flow rates (m3/h)

470

480

490

500

510

520

530

540

550

560

ToA

s o

f u

ltra

son

ic s

ign

al

(µs)

Tx1 - Rx (17~20)

Tx1 - Rx (21~24)

Tx1 - Rx (25~28)Tx1 - Rx (29~32)

0 500 1000 1500 2000 2500

Flow rates (m3/h)

450

460

470

480

490

500

510

520

ToA

s o

f u

ltra

son

ic s

ign

al

(µs)

Tx1 - Rx (17~20)

Tx1 - Rx (21~24)Rx1 - Tx (17~20)

Rx1 - Tx (21~24)

Rx1 - Tx (25~28)

Rx1 - Tx (29~32)

Upstream

Downstream

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Upstream Downstream

40

38

36

34

32

30

28

26

24

220 500 1000 1500 2000 2500

Flow rates (m3/h)

Ste

erin

g a

ng

le (

o)

Variation of optimum steering angle with flow rates

17

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5 Flow measurement tests

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5 Flow measurement tests

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6 Summary and Future ResearchSummary

• The design, the fabrication and the characterization of two-dimensional

flexural ultrasonic phased arrays are presented;

• Flow measurements with the arrays are conducted and the results

closely correlate with those measured by a calibrated mechanical flow

meter;

• Flexural ultrasonic phased arrays are a potentially economic and low-

voltage solution for flow measurement with higher accuracy and larger

range.

Future Research

• Compare various data fusion technologies to further improve accuracy;

• Carry out multi-path flow measurement using the 2D phased arrays.

CIU Centre for Industrial Ultrasonics www.ciu.ac.uk

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Flow Measurement based on two-dimensional

Flexural Ultrasonic Phased Array

Thank you for your attention!

Dr. Lei Kang

Research Fellow

Centre for Industrial Ultrasonics

University of Warwick

Email: L.Kang.1@warwick.ac.uk

CIU Centre for Industrial Ultrasonics www.ciu.ac.uk