A novel ECT-EST combined method for gas-solids flow pattern and charge distribution visualization

A non-invasive measurement method of visualizing the flow pattern and charge distribution of gas-solid two-phase flow has been applied to flow measurement in a gravity-dropping conveyance system and a pneumatic conveyance system. The permittivity distribution acquired from an ECT (Electrical Capacitance Tomography) can be used to improve the iteration accuracy in establishing charge sensitivity field of an EST (Electrostatic Tomography), hence to reduce the uncertainty of inverse calculation of charge distribution. The experimental results show that, for the gravity-dropping system, charge density increases with particle concentration, whilst in the pneumatic conveyance system, charge density decreases in the area where the particle concentration is higher. The total charge intensity decreases with the increase of the concentration of pulverized coal in the pipe.