压力脉动法预测声场流化床最小流化速度

在内径140 mm,高1 600 mm的鼓泡流化床中,采用压力探针研究了声场流化床FCC和石英砂颗粒的流化特性,考察了声压级和频率对颗粒最小流化速度的影响。结果表明:无声场条件下,压力脉动标准方差随表观气速的增大而线性增大,声场的引入可以显著降低颗粒最小流化速度,声压级越大颗粒的最小流化速度越小;固定声压级改变声波频率,发现频率在300 Hz时颗粒最小流化速度最小。对不同声场条件下最小流化速度进行拟合,得到了声场流化床最小流化速度预测关联式。

Evaluation of the Minimum Fluidization Velocity in an Acoustic Fluidized Bed by Pressure Fluctuation Measurement

The pressure fluctuation of the FCC and quartz sand particles were described using an pressure transducer probe in a bubbling fluidized bed(140 mm×1 600 mm).The effects of sound wave frequency and sound pressure level on the pressure fluctuation were examined in this work.The experimental findings indicate that the standard deviation of pressure fluctuations is increased linearly with increasing superficial gas velocity without acoustic field.The minimum fluidization velocity decreased with an increase in sound pressure level at the same sound frequency.The minimum fluidization velocity has a minimum value when the frequency of sound waves reached 300 Hz.On the basis of the experimental data,a correlation was developed to calculate the minimum fluidization velocity in an acoustic fluidized bed.