Capacitive measuring system for two-phase flow monitoring. Part 2: Simulation-based calibration

• Simulation-based approach for capacitive probe calibration is described.
• FEM simulations for the different flow patterns are performed.
• Proposed calibration method is superior than simple normalization method.
• The approach presented can be also applied to other types of capacitive probes.

Two-phase gas–liquid flows are present in many industrial processes and therefore monitoring of such flow is highly desired for either quality or efficiency assurance. Capacitive probes are widely used for two-phase investigation in experimental facilities and may have the potential for industrial use in the future. In this paper, we apply a simulation-based approach for increasing the accuracy of void fraction measurement of capacitive probes. We also employ the simulation data to find the electric response of a capacitive probe under different flow conditions. Moreover, by means of a horizontal flow test bench, we compare the void fraction measurements of the capacitive probe with the output of a reference wire mesh sensor. Experimental tests for air–water flow were performed. We show that from simple normalization approach (as widely employed) average deviation of measured void fraction values (compared to reference sensor) can be heavily reduced from up to 30% to less than 5% in most cases. The approach presented can be also applied to other types of capacitive probes.