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采用压差传感器在方形流化床中测试了多个床层截面的压力波动,研究了从鼓泡流态化到湍动流态化条件下气固方形床中截面平均压力梯度及其波动标准差的变化行为,获得了转变速度Uc,结合不同形式的圆形流化床关联式,采用当量直径方法对此流化床进行了转变速度的计算。比较分析的结果表明:通过当量直径的计算方法得出的转变速度与在相同操作条件下首先发生转变的床层上部的转变速度接近,说明用当量直径的方法是可行的。同时,发现床内流型的转变不是同时发生于整个床层的瞬时行为,而是由床层上部逐层向下扩展的递进行为,表明转变速度与床体尺寸及床层截面高度有关。
The pressure fluctuation of several bed sections was tested in a square fluidized bed using a differential pressure sensor. The average pressure gradient of the cross section in a gas-solid square bed under the condition of bubbling fluidized to turbulent fluidized bed was studied. In this paper, the transformation speed Uc was obtained. Based on the correlation of different forms of circular fluidized bed, the equivalent diameter method was used to calculate the transition speed of this fluidized bed. The results of comparative analysis show that the transformation speed obtained by the calculation of equivalent diameter is close to that of the upper part of the bed under the same operating conditions. It is feasible to use the equivalent diameter method. At the same time, it is found that the transition of bed flow pattern does not occur instantaneously in the whole bed at the same time, but rather the progressive behavior of the upper part of the bed spreading downward from the upper part of the bed, indicating that the transition speed is related to the bed size and the bed section height.