水力旋流器内部流场的数值研究

Numerical Study on Internal Flow Field of Hydrocyclone

在PIV实验验证的基础上,利用RSM雷诺应力模型和VOF两相流模型对50 mm水力旋流器内部流场进行了系统的数值研究.结果表明:旋流器内静压从器壁至中心逐渐下降,静压为0处即为空气柱边界,空气柱内为负压,空气柱的存在增加了分级过程的能量消耗;旋流器内切向速度分布符合组合涡特征,内部为强制涡运动,外部为半自由涡运动;零速包络面是轴向速度方向发生改变的转折面,其上部为柱形,下部为锥形,柱形段直径约为溢流管的2.3倍;在外旋流区域径向速度方向从旋流器器壁指向中心,内旋流区域存在方向相反、位置相对的径向速度,空气柱内径向速度基本为0.

By using RSM （Reynolds stress model）turbulence model and VOF （volume of fluid） two-phase flow model, systematic numerical study on internal flow field of φ50 mm hydrocyclone was carried out, which had been validated by PIV （particle image velocimetry ）measurement results. It shows that internal static pressure of hydroclone gradually declines from wall to center, the static pressure is zero at the boundary of air core, the interior of air core is negative pressure, and additional energy is consumed by air core when the hydrocyclone works. Tangential velocity distribution could be regarded as a combined vortex, inside is forced vortex and outside is quasi- free vortex. The envelope of zero vertical velocity is a turning surface of axial velocity change, its upside is cylinder and its lower part is cone. The diameter of the cylindrical section is 2.3 times as large as overflow outlet diameter. Radial velocity direction is from the wall of the hydrocyclone toward the center in the outer vortex area, radial velocities of opposite direction and relative position exist in the inner vortex area, and radial velocity inside air core is almost zero.