Dense-phase pneumatically conveyed coal particle velocity measurement using electrostatic probes

Abstract

The fundamental measurement theory of an electrostatic probe and cross-correlation velocity measurement method are introduced in this paper. The effects of the probe's geometric parameters, including the length of the probe; the thickness, length and 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 ( τ 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 m 3/m 3. The experimental results that were obtained demonstrate that the system is capable of providing solid particle velocity measurements with repeatability better than 10% under the given experimental conditions.