Effect of particle distribution on electrostatic tomography system
23 Mar 2012-Vol. 1428, Iss: 1, pp 269-276
TL;DR: In this paper, the effect of different particle flow regimes on electrostatic tomography (EST) is investigated numerically and experimentally, and the effect relates to the relationship between the charge distribution and the particle distribution.
Abstract: Particle is charged due to frictional contact and collisions between particles and pipe wall. Electrostatic tomography technology (EST) is used to monitor the traveling particle charge. However the electric field distribution in the electrostatic sensor arrays is simultaneously affected by both the particle permittivity distribution and particle charge. In the paper, the effect of the different particle flow regimes on EST is investigated numerically and experimentally. Results indicated the particle distribution affected the induced charge on the electrostatic sensor array. But the effect relates to the relationship between the charge distribution and the particle distribution. Furthermore, a fusion of dual modality tomography system consisting of a capacitance sensor and electrostatic sensor arrays is used to investigate the relationship between the particle distribution and charge distribution in a gravity conveying rig. Results showed that the higher particle concentration has higher charge distribution in the gravity conveying rig. Additionally, the measurement of the mass flow rate by EST was investigated.
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TL;DR: A non-invasive measurement method of visualizing the flow pattern and charge distribution of gas-solids two-phase flow has been studied and verified using gravity-dropping and pneumatic conveyance rigs with pulverized coal as solids as discussed by the authors.
Abstract: A non-invasive measurement method of visualizing the flow pattern and charge distribution of gas–solids two-phase flow has been studied and verified using gravity-dropping and pneumatic conveyance rigs with pulverized coal as solids. It has been proven that the permittivity distribution acquired from an electrical capacitance tomography (ECT) system can be used to improve the accuracy in establishing charge sensitivity field of an electrostatic tomography (EST) system, and to reduce the uncertainty of charge distribution reconstruction. The experimental results show that, under the given experimental conditions for the gravity-dropping system, charge density increases with particles' concentration, whilst in the pneumatic conveyance system, charge density decreases in the area where the particles' concentration is higher, and the total charge intensity decreases with the increase of the concentration of pulverized coal in the pipe. The method proposed in this paper is potentially important in pneumatic processes for charge distribution measurement and safe operations. It is envisaged that with further development, this technique can provide information for investigation into the mechanism of inter-particle force on electrostatic attraction and repulsion.
17 citations
TL;DR: In this paper, the sensitivity characteristics of electrostatic sensors have a direct influence on monitoring accuracy, and spatial sensitivity characteristics have also been studied in the context of monitoring systems with spatial sensors.
Abstract: Electrostatic sensors are key components of electrostatic monitoring systems. Their sensitivity characteristics have a direct influence on monitoring accuracy. In previous studies, spatial sensitiv...
11 citations
16 Jul 2012
TL;DR: In this paper, a non-invasive measurement method of visualizing the flow pattern and charge distribution of gas-solid two-phase flow has been applied to flow measurement in a gravity-dropping conveyance system and a pneumatic conveance system.
Abstract: A non-invasive measurement method of visualizing the flow pattern and charge distribution of gas-solid two-phase flow has been applied to flow measurement in a gravity-dropping conveyance system and a pneumatic conveyance system. The permittivity distribution acquired from an ECT (Electrical Capacitance Tomography) can be used to improve the iteration accuracy in establishing charge sensitivity field of an EST (Electrostatic Tomography), hence to reduce the uncertainty of inverse calculation of charge distribution. The experimental results show that, for the gravity-dropping system, charge density increases with particle concentration, whilst in the pneumatic conveyance system, charge density decreases in the area where the particle concentration is higher. The total charge intensity decreases with the increase of the concentration of pulverized coal in the pipe.
7 citations
TL;DR: The proposed dynamic sensitivity of ESA, as well as the array signal processing algorithm are expected to provide references in modeling, designing and using ESAs.
Abstract: Electrostatic sensor arrays (ESAs) are promising in industrial applications related to charged particle monitoring. Sensitivity is a fundamental and commonly-used sensing characteristic of an ESA. However, the usually used spatial sensitivity, which is called static sensitivity here, is not proper for moving particles or capable of reflecting array signal processing algorithms integrated in an ESA. Besides, reports on ESAs for intermittent particles are scarce yet, especially lacking suitable array signal processing algorithms. To solve the problems, the dynamic sensitivity of ESA is proposed, and a hemisphere-shaped electrostatic sensors’ circular array (HSESCA) along with its application in intermittent particle monitoring are taken as an example. In detail, a sensing model of the HSESCA is built. On this basis, its array signals are analyzed; the dynamic sensitivity is thereupon defined by analyzing the processing of the array signals. Besides, a component extraction-based array signal processing algorithm for intermittent particles is proposed, and the corresponding dynamic sensitivity is analyzed quantitatively. Moreover, simulated and experimental results are discussed, which validate the accuracy of the models and the effectiveness of the relevant approaches. The proposed dynamic sensitivity of ESA, as well as the array signal processing algorithm are expected to provide references in modeling, designing and using ESAs.
6 citations