板式塔工作状态下自振周期的计算

Calculation of self-vibrating cycle of tray column under working conditions

板式塔在工作状态下,塔体受到横向载荷,塔板发生倾斜,板上存留介质的液面仍保持水平,介质的质心偏离塔体的轴线。由于介质质心的偏离,塔体发生横向振动时,板上的介质对塔体产生附加的偏心惯性力,所有塔板上的附加偏心惯性力累加将对塔体自振周期产生较大影响。通过推导介质质心的偏心距公式,得到适合于工作状态下板式塔的传递矩阵。通过实例计算与对比的结果表明,由于附加偏心惯性力的存在,工作状态下的板式塔的各阶自振周期都有所增加,高阶振型的自振周期的增加幅度大于低阶振型的自振周期。

The column plate inclines when the tray column is subjected to lateral loads under the operating conditions. The centroid of liquid on the column plate deviates from the axis of the column, because the liquid level on the column plate keeps horizontal surface. The change of the centroid of media on every column plate produces additional eccentric inertial force when the tray column takes place lateral vibration. The additional eccentric inertial force of all trays in accumulation has a greater impact on the self-vibrating cycle of the tray column. By means of establishing reasonable mechanical model, the formula of eccentricity for the centroid of media is deduced. Considering the effect of additional eccentric inertial force, the transfer matrix that applies to tray column under the working conditions was revised, and the self-vibrating cycle of tray column was calculated making use of it. The results show that the self-vibrating cycle of tray column increases owing to the existence of additional eccentric inertial force, especially the top tower that has a lot of column plate. With the increase of vibration mode, the impact on the natural period increases more.