Dense-phase pneumatically conveyed coal particle velocity measurement using electrostatic probes and cross correlation algorithm

The fundamental measurement theory of an electrostatic probe and cross-correlation velocity measurement method are introduced in the paper. The effects of the probe's geometric parameters including the length of the probe, the thickness, the length and the relative permittivity of the dielectric pipe, the radius of the screen on the dimensionless calibration coefficient (k) and the statistical error of the transit time (?m) of the correlation velocity measurement system using electrostatic probes were investigated theoretically. Finally the measurement system was applied in a 10 mm bore horizontal section of a dense phase pneumatic conveying system under high pressure circulating pulverized coal over a superficial air velocity range of 0.5-7 m/s for a particle concentration 0.052-0.141 m3/m3. Experimental results obtained demonstrate that the system is capable of providing solid particle velocity measurements with repeatability better than 10 % under the given experimental conditions.