关键词: 声场, 高温, 流化床, 声压, 声场频率, 最小流化速度, 压力波动偏差

Abstract: The flow characteristics in a bubbling fluidized bed of 50 mm i.d. and 1000 mm in height under sound excitation at high temperatures were investigated. With Geldart A, B group particles as fluidized materials, the effects of bed temperature, acoustic frequency and the sound pressure level (SPL) on the minimum fluidization velocity were examined in detail. It is demonstrated that the minimum fluidization velocity decreases with increasing temperature. At a given temperature and sound frequency, the velocity decreases with increasing SPL. At the same SPL and temperature, there always exists an optimal frequency range. As the sound frequency increases, the velocity decreases firstly and then increases. Based on the statistical analysis of pressure fluctuation signals, the criterion of influence on the fluidization quality at high-temperature fluidized bed was presented. The experimental results indicate that the pressure standard deviation and the minimum fluidization velocity decreases when the SPL is beyond 110 dB and acoustic frequency between 100~200 Hz.

Key words: acoustic wave, high temperature, fluidized bed, sound pressure level, sound frequency, minimum fluidization velocity, pressure standard deviation