Characterisation of pulverised fuel flow in a square-shaped pneumatic conveying pipe using electrostatic sensor arrays

Square-shaped pneumatic conveying pipes are used in some industrial processes such as fuel injection systems in coal-fired power plants and circulating fluidized beds. However, little research has been undertaken to characterise the gas-solid two-phase flow in square-shaped pneumatic conveying pipes. This paper presents novel non-intrusive electrostatic sensor arrays for measuring pulverised fuel in such pipes. The sensor arrays consist of 12 pairs of strip-shaped electrodes which are uniformly embedded in the four flat pipe walls. Experiments have been conducted on a laboratory scale test rig under a range of conditions. The fuel velocity and flow stability profiles over the whole cross-section of the square-shaped pipe are presented in this paper. Experimental results demonstrate that the proposed non-intrusive electrostatic sensor arrays are capable of characterising the velocity and flow stability profiles of pulverised fuel flow in square-shaped pneumatic conveying pipes.