基于自激振荡的低速气力输送节能试验

Experimental Study on the Low-velocity Self-excited Pneumatic Conveying System

目前气力输送设备的开发与应用仍然局限在忽视能耗的粗放型阶段。基于此拟在水平管气力输送系统物料入口上游处安装自由摆动的软翅以产生自激振荡流,实现系统节能降耗的目的。首先,通过试验测量系统的压力损失、最佳输送速度并计算能量损失系数,结果表明:相对于传统输送,自激振荡流能有效降低气力输送系统的最佳输送速度和能量损耗,最大减小量分别为15.2%和25.5%。然后,采用粒子成像测试技术(PIV)测量不同工况下的粒子流型及粒子速度,发现低速输送时自激振荡流可以避免颗粒沉积,增大粒子的轴向和悬浮速度;同时采用快速傅里叶变换(FFT)方法,分析不同工况下的粒子脉动速度,发现自激振荡流作用下的粒子速度脉动强度大于传统输送,揭示了自激振荡流的节能机理。

The development and application of pneumatic conveying equipment is still confined to ignore the energy consumption of the extensive stage. The self-excited oscillation flow, generated by the soft fin mounted in the entrance of pipeline, is applied in the horizontal pneumatic conveying in order to promote pneumatic conveying system and save the system energy. First, the pressure drops and minimum, the critical velocities and the power consumption coefficient are measured and calculated, which results show that the minimum and critical velocities and power consumption are reduced by the self-excited oscillation flow, and the maximum reduction is 15.2% and 25.5%, respectively. Then, the particles flow regime and particle velocity are measured by using by using particle image velocimetry(PIV), and found that low speed conveyor with the self-excited oscillation flow can avoid particle deposition, increasing the particle axial and suspension velocity; at the same time, the particle fluctuation velocity is analyzed under different cases using fast Fourier transform (FFT) method, it is found that the particle velocity fluctuation intensity with the self-excited oscillation flow is larger than the traditional transport, reveals the energy-saving mechanism of the self-excited oscillation flow.