Real-time solid flow velocity measurement based on a microwave sensor

Abstract

Measurement and control of bulk solid flows become increasingly important in industries, such as large-scale production, coal transportation and food processing, although rapid and accurate velocity measurement is still a challenging task in these applications. This paper presents a new velocity measurement method based on a microwave sensor operated at 10.525 GHz and investigates the factors that affect velocity of bulk solid flows and the velocity of the solid particles in order to quantify the flow and improve the efficiency of transportation. In this method, a microwave Doppler Signal Analyser is adopted to calculate the average velocity of bulk solid flows and obtain the instantaneous velocity of a single solid flow. The influence of air friction, pipe collision and particle interactions is also analysed with experiments. The measurement results show that the average velocities of bulk solid flows range from 0.6 to 1.6 m/s, and the interaction between solids play a major effect on solid movements. The effect of pipe wall friction should also be considered. Besides, the mass flow rate and the total mass of bulk solid flow can be calculated. The mass flow rate ranges from 0 kg/s to 0.21 kg/s in the entire experiment.