Velocity measurement of pneumatically I conveyed solids using electrodynamic I sensors

Theoretica and expermental studies of cross conelation techniqJes appliea io non-resrrictive velocity measuement of pneumatically conveyed solids using ringshaped electrodynamic flow sensors are presentea. In-deptn studies of the electrodynamic sensing mechanism, and also of the spat al sensitivity and spatial filtering propenies of the sensor are incldded, together with heir relationships to measurement accuracy and the effects of solids' velocity prof:les. The experimental evaluation of a 53 mm bore sensing head is descr bed, ncluding tnals us.ng a calibrated pneumatic conveyor circLlat ng pulverized fuel and cement. Comparisons of test results with the mathematcal moaels of the sensor are used to identify important aspects of the instrLment design. OH-line test results obtained using gravity-fed solids flow show that the system repeatab lily :s w.thin -LO.S% over the velocity range of 2-4 m s-' for volumetric concentrations of solids no greater than 0.2%. Results obiained in the pilot-plant tr.als demonstrate that the system is capable 01 achieving repeatab.lity better than &2% and linearity wi1h.n 12% over the veloc.ty range 20-40 m s-' for volJmetric concentrations of solids in the range 0.01-0.44%.