Experimental investigation on heat transfer mechanisms of pneumatically conveyed solids' plugs as a means to mass flow rate measurement

Experiments with a gas-solids dense phase pneumatic pipe flow have been undertaken: (1) to determine the average heat transfer coefficient between a heated wall and a gas-solids dense phase flow; (2) to investigate the heat transfer mechanisms of pneumatically conveyed dense phase flow in detail as the system operates by injecting heat energy into the pipeline to heat the pipe section, as a result, to heat the dense phase gas-solids' plugs, and measuring the resultant change in solids' plug and heated wall's temperatures. The experimental results suggest that the average heat transfer coefficient between the heated wall and the gas-solids dense flow displays an approximately linear relationship with the solids loading ratio. A larger solids' loading ratio results in a higher average heat transfer coefficient. The results have been compared with those of Moriyama et al. although the overlap of data ranges is limited. Experimental results also indicate that the inner wall temperature is able to reflect the energy change when each solids' plug is being through the heated region. The calculated gradient change of the outer wall temperature-time history T-1 measured is consistent with the fluctuation of the wavering of the inner wall temperature along with the present of solids' plugs in the heated region. (C) 2014 Elsevier Ltd. All rights reserved.