Twin-array capacitance sensor for multi-parameter measurements of multiphase flow

•A simplified method for measuring multiphase flow using an array capacitance sensor was proposed.•Non-uniformity of sensitivity map was used to directly extract regional concentrations.•With this method, the number of measured capacitances can be reduced largely.

We propose a twin-array capacitance (TAC) sensor for the measurement of concentration, velocity, and flowrate of gas–solid two-phase flow. Using the sensitivity non-uniformity of a neighboring electrode, the regional concentration of the cross-section was reconstructed directly. Additionally, the finite element method was used to analyze the capacitance of the sensors composed of a different number of electrodes. TAC sensors with 4, 6, and 8 electrodes were found to be the best for regional concentration measurements. Based on this, the 8-electrode twin-plane electrical capacitance tomography (ECT) sensor, the 4-electrode TAC sensor, and the 6-electrode TAC sensor were used to measure the concentration, velocity, and flowrate of granules in granular flow. The flowrates measured by ECT and TAC were compared with the flowrate obtained by a gravity sensor to verify the measurement accuracy. Experiments on vertical and inclined pipelines with granular flow were carried out. We found that the flowrate accuracy of the 4-electrode TAC is distinctly better than that of the 6-electrode TAC in the vertical pipeline while the flowrate accuracy of the 4-electrode TAC and the 6-electrode TAC were similar for the inclined pipeline.

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