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EXTENSIBLE ELECTRICAL CAPACITANCE TOMOGRAPHY

SYSTEM FOR GAS–LIQUID TWO-PHASE FLOW

Chairman :Hung -Chi YangPresenter: Han-Yang Liu

Adviser :Dr. Ji- Jer Huang

From S. Xin H. Wang, “Extensible electrical capacitance tomography systemfor gas–liquid two-phase flow” IET Image Process., 2011, Vol. 5, Iss. 5, pp. 500–507

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OutlineIntroduction

Materials and Methods

Conclusions

References

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IntroductionApplications of electrical capacitance tomography (ECT)

oil pipelines

chemical applications

fluidized beds

pneumatic conveying

trickle bed reactors

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Introduction Gas/liquid two-phase flow systems are often

encountered in many chemical and industrial processes

oil-gas two-phase flow in the petroleum industry

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IntroductionElectrical capacitance tomography (ECT)

Non-invasive imaging technology

flow regime identification of the two-phase flow

void fraction measurement of the two-phase flow

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IntroductionFPGA acts Microcontroller A high-speed data

transmission unit

DSP performs only as a coprocessor for ultra high speed

data processing for reconstruction algorithm

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IntroductionAn ECT system commonly contains three main units

The sensor array

The sensing electronics

The computer system

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IntroductionThe identification results of stratified flow, wavy stratified

flow, plug flow and slug flow

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IntroductionThe new system can support 16 or 32 electrodes working

in multi-frequency model

An additional ERT system can be easily embedded into the new ECT system for dual imaging of permittivity and conductivity to form a dual-modality system

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Materials and Methods

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Materials and MethodsFPGA is the most important part of the ECT system

Logical controlsData processing Data transfer

DSP is mainly in charge of reconstruction algorithm in this system

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Materials and MethodsECT sensing electrode array was established by using the

software COMSOL.

The uniformity of sensitivity field distribution

The correlation coefficient

The reconstructed image space resolution

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Materials and Methods

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Materials and Methods

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Materials and Methods

Direct Digital Synthesiser (DDS)

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Materials and Methods

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Materials and Methods Multi-frequency demodulation

Discrete Fourier transform (DFT) demodulation

Quadrature demodulation

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Materials and MethodsDFT demodulation sampling frequency and data length

Amplitude and phase angle of sineMeasured signal will correspond with with the frequency

point Complex impedance

DFT (non-integer-period sampling)Energy leakageFence effect

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Digital quadrature demodulation

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Materials and Methods

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Materials and Methods

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Conclusions

L ?1000

L =1000, 79.8 dB

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Conclusions

All the images are obtained using LBP algorithm

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Conclusions

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Conclusions

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ConclusionsSNR of this system is up to 79.8 dB

Real-time imaging speed is about 280 frames/s

Dual-frequency model with LBP algorithm

High real-time and smaller average error

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Thank you for your attention

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ReferencesJ. Braz. Soc. Mech. Sci. & Eng. vol.27 no.1 Rio de

Janeiro Jan./Mar. 2005S. Xin H. Wang, “Extensible electrical capacitance

tomography system for gas–liquid two-phase flow” IET Image Process., 2011, Vol. 5, Iss. 5, pp. 500–507

Ziqiang Cui1, HuaxiangWang, Zengqiang Chen1,

Yanbin Xu andWuqiang Yang, “A high-performance digital system for electrical capacitance tomography” Meas. Sci. Technol. 22 (2011) 055503 (10pp)