Preliminary study on ECT imaging of flames in porous media

Liu, S; Chen, Q; Xiong, Xiaopeng; Zhang, Z; Lei, Jing

doi:10.1088/0957-0233/19/9/094017

Cited by 49 publications

(26 citation statements)

References 28 publications

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“…However, due to the existence of uncertain residuals associated with the sampling data, exact solution of θ is not available even if enough equations are established as Eq. (8). Therefore, it is necessary to employ a parameter estimation method to solve this problem.…”

Section: A Mathematical Modelmentioning

confidence: 99%

“…5 Since its birth in early 1980s, both measurement techniques and image reconstruction algorithms for ET have been widely developed, and up to now, the technique has been applied in many industrial processes, e.g., multiphase flow measurement, 6 fluidized bed visualization 7 and flame monitoring. 8 ET is generally expected to capture the dynamic processes that are rapidly changing. [9][10][11] However, image reconstruction for ET is an ill-posed problem, and small errors of the boundary measurements will lead to low-quality images.…”

Section: Introductionmentioning

confidence: 99%

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A recursive least squares-based demodulator for electrical tomography

Zhou

Cao

2013

Review of Scientific Instruments

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In this paper, a recursive least squares (RLS)-based demodulator is proposed for Electrical Tomography (ET) that employs sinusoidal excitation. The new demodulator can output preliminary demodulation results on amplitude and phase of a sinusoidal signal by processing the first two sampling data, and the demodulation precision and signal-to-noise ratio can be further improved by involving more sampling data in a recursive way. Thus trade-off between the speed and precision in demodulation of electrical parameters can be flexibly made according to specific requirement of an ET system. The RLS-based demodulator is suitable to be implemented in a field programmable gate array (FPGA). Numerical simulation was carried out to prove its feasibility and optimize the relevant parameters for hardware implementation, e.g., the precision of the fixed-point parameters, sampling rate, and resolution of the analog to digital convertor. A FPGA-based capacitance measurement circuit for electrical capacitance tomography was constructed to implement and validate the RLS-based demodulator. Both simulation and experimental results demonstrate that the proposed demodulator is valid and capable of making trade-off between demodulation speed and precision and brings more flexibility to the hardware design of ET systems.

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Section: A Mathematical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A recursive least squares-based demodulator for electrical tomography

Zhou

Cao

2013

Review of Scientific Instruments

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“…When an ECT system is used to monitor a rapidly-changing process, e.g., an ignition process of a flame which is typically a pulsating process, or used for velocity measurement, high-speed data acquisition is required to provide high temporal resolution [3], [9]- [12]. For example, when the ECT system is used to study the pulsating characteristics of the flame in the pulse combustor whose pulsation frequency is about 200 Hz [13], a data acquisition rate faster than about 400 frames per second is required for an ECT system to capture the basic frequency information of the flame.…”

Section: Introduction Lectrical Capacitance Tomography (Ect) Is Anmentioning

confidence: 99%

A High-Speed Digital Electrical Capacitance Tomography System Combining Digital Recursive Demodulation and Parallel Capacitance Measurement

et al. 2017

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Abstract-Two means can be used to improve the data acquisition rate of the ECT system with a fixed excitation frequency, i.e. improving the capacitance measurement speed or changing the capacitance measurement mode from serial to parallel. This paper presents a newly developed high-speed electrical capacitance tomography (ECT) system by combing digital recursive demodulation and parallel-mode capacitance measurement methods. By using the digital recursive demodulator, the time-cost for one time of capacitance measurement can be one period of the excitation sinusoid or less. By using the parallel-mode capacitance measuring unit, capacitances between the exciting electrode and all other measuring electrodes can be measured simultaneously. The data acquisition rate of the parallel-mode ECT system with a sensor of N electrodes is N-1 times of a traditional serial-mode ECT system with the same excitation frequency. When the excitation frequency is 100 kHz and 0.6 periods of data are used for signal demodulation, the data acquisition rate can reach up to 15150 frames per second. The developed system together with a heat-resisting circular ECT sensor with 12 electrodes was used to monitor the ignition process of a cylindrical flame generated by a Bunsen burner. Experimental results show that the ECT system can locate the position and capture the dynamic process of the flame with a high temporal resolution.

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“…Compared with X-ray tomography, ECT possesses the advantages of no radiation, fast response, robustness, and simple structure. It is considered as a promising technology for many industrial applications, such as multiphase flow measurement in pipelines (Ismail, Gamio, Bukhari, & Yang, 2005), choking transition in gasesolid risers (Du, Warsito, & Fan, 2006a), flames in porous media (Liu, Chen, Xiong, Zhang, & Lei, 2008), mass flow measurement of pneumatically conveyed solids (Sun, Liu, Lei, & Li, 2008), solids distribution measurement in a cyclone separator (Wang, Liu, Jiang, & Yang, 2004), and the analysis of dynamic processes in fluidized beds (Du, Warsito, & Fan, 2006b). The key issue of ECT is to reconstruct the permittivity distribution from a set of electrical capacitances measured on the boundary of the region of interest (ROI).…”

Section: Introductionmentioning

confidence: 99%