Accurate measurement 1 Asymmetric electrodes 1 Calibration 1 Calibration method 1 Capacitance 1 Capacitance measurement 1 Capacitance sensors 1 Electrodes 1 Flow patterns 1 Horizontal flows 1 Macro-tubes Quick-closing valve 1 R32 refrigerant 1 Real time measurements 1 Refrigerants 1 Void fraction 1 Void fraction sensor 1 calibration method 1 capacitance sensor 1 quick-closing valve 1 real-time measurement 1 void fraction 1