Eliminating the Influence of Moisture on Solid Concentration Measurement in Gas–Solid Flows Using Combined Sensors

In gas–solid two-phase flows, the situation that moisture in the solid changes is often encountered. The varying and unknown moisture brings new challenges to the solid concentration measurement if the used measurement method is sensitive to moisture. In this study, a new method that can eliminate the influence of moisture on the measurement of solid concentration in gas–solid flows is proposed. First, the new combined sensors consisting of the microwave transmission sensor and the capacitance sensor are proposed, and the measurement systems are designed. Both the microwave transmission sensor and the capacitance sensor are sensitive to moisture and solid concentration, and they can acquire information about the solid concentration and moisture simultaneously. Then an effective decoupling method is proposed to derive moisture and solid concentration from the information acquired by the microwave transmission sensor and the capacitance sensor. Experiments are carried out to simulate the flow structure of roping flow to verify the proposed method. The results indicate that the influence of moisture on the measurement of solid concentration can be eliminated, and the moisture-independent measurement of solid concentration in gas–solid flows can be realized.