Capacitive measuring system for two-phase flow monitoring. Part 1: Hardware design and evaluation

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

“…That way, the oscillation period T of the electric field accounts for 200 ns. Considering that the capacitive sensor length is about 10 cm [5], the propagation time of an electromagnetic wave through it would be of 333.3 P T ps (with a speed of 8 3.10 c m/s). As P T T , the electromagnetic coupling is negligible and the use of the electroquasistatic field model is feasible.…”

“…Fig. 5 shows the electrode set of the sensor, which was described in detail in [5]. We maintained the detection, guard and shield electrodes at ground potential and applied 1V to the source electrode.…”

“…The circuit used for capacitance measurement was already described in [5]. In that work we derived two equations that relate the output voltage to the probe impedance.…”

“…In [5] we presented the development of a capacitive sensor for void fraction measurement. Capacitive sensors are non-intrusive [6], low cost and have high temporal resolution [7].…”

“…First the response curves for stratified, dispersed bubbles and annular flow are obtained. Based on the simulation results we calculate the theoretical voltage output and sensibility of the measurement system, which was already described in [5]. We also propose a method for void fraction calculation without the need of flow pattern identification.…”