渐变截面型入料口夹角对旋流器流场及压降的影响

Effects of Inlet Angle on the Flow Pattern and Pressure Drop of a Hydrocyclone with Gradual Change Section Type Inlet

利用RSM雷诺应力模型和VOF多相流模型,通过数值试验方法考察了渐变截面型入料口夹角对Φ50 mm水力旋流器流场及压降的影响.结果表明,增大入料口夹角,切向速度增加,致使分离效率提高;与此同时,轴向速度和溢流管底端的最大径向速度也随之相应增加,导致沉砂分流比略有降低、短路流量增加,但对湍流结构影响不明显;空气柱直径同样随着夹角的增加而增大,从而有效分选空间减小.旋流器内部的压力损失主要包括主分离区域的损失和入料口区域的损失;增大入料口夹角,总压降增加,导流能力增强,当夹角为20°时,导流性能最优,但能量利用率降低.

The effects of inlet angle on the flow pattern and pressure drop in 050 mm hydrocyclones have been investigated numerically by means of Reynolds stress model （RSM） and volume of fluid multi-phase flow model（VOF）. Results show that the tangential velocity increases by increasing the inlet angle,leading to the increase of collection efficiency. Meanwhile,the mass of short-circuit flow can be enhanced and the split ratio can be decreased through increasing the axial velocity and the maximum radial velocity under the vortex finder caused by increasing the inlet angle. Besides,no significant influence on turbulence structure has been found as the inlet angle increases. The air core diameter also increases with the increase of the inlet angle,reducing the effective separation space. The hydrocyclone pressure drop is mainly generated by the pressure losses in the hydrocyclone body （ under vortex fin de r） and in the inlet section. There is an increase in the pressure drop and the power of guiding and accelerating the input flow with increasing of inlet angle,while there is a decrease in energy utilization efficiency. Furthermore, the optimum guiding and accelerating effect is obtained with an inlet angle of 20°.