Flow characteristics in an acoustic bubbling fluidized bed at high temperature

The pressure fluctuation of the quartz sand and SiO2 particles was investigated using pressure transducer in high temperature fluidized bed with sound assistance. The effects of bed temperature, sound wave frequency, and sound pressure level (SPL) on the pressure fluctuation were examined. It indicates that the minimum fluidization velocity decreases with an increase in sound pressure level at the same sound frequency. At the same SPL and bed temperature, there always exists an optimal frequency range achieving good fluidization quality. As the sound frequency increases, the minimum fluidization velocity decreases firstly and then increases. Based on the statistical analysis of pressure signals, the effect of sound frequency on the fluidization quality at high-temperature fluidized bed was presented. On basis of discrete wavelet transform, an original signal was resolved into five-detailed scale signal. Furthermore, the peak frequency for Scale 3 detail signal represents the bubbling frequency.