Abstract
Pressure fluctuations were measured in a two-dimensional gas-solid fluidized bed at temperatures ranging from 13 to 270°C. The random pressure fluctuation signals were studied on-line by the statistical method. The results indicate that the frequency spectrum, major frequency, and mean pressure amplitude depend considerably on the gas excess velocity and temperature. A probability density function of pressure fluctuations with two peaks was observed in the upper portion of the bed, indicating bubble eruption behavior at room temperature. The two peaks in the p.d.f. are transformed into a single peak at higher temperature, and the location of maximum amplitude also changes at higher temperature. Both measurements of pressure drop fluctuations and differential pressure fluctuations were used in this study, and the latter were found to be superior in the study of bubble behavior.
