水力旋流器内部流体流动特性PIV实验

A PIV experimental study on fluid flow characteristics in hydrocyclone

为了研究水力旋流器内部流体流动特性,利用激光粒子测速技术(PIV)对双切向入口双锥水力旋流器内部流体流动的全流场进行了测量,利用Tecplot进行了流场显示,切向速度、轴向速度和径向速度提取及涡量计算,并绘制了零轴向速度包络面(LZ-VV)。研究了不同流量条件下,水力旋流器旋流腔中流体的切向速度和径向速度分布特点、上锥段中流体轴向速度分布特点、上锥段中流体局部涡量特征、上锥段中流体零轴向速度包络面(LZVV)的分布特性。结果显示,水力旋流器旋流腔中的流体切向速度呈中心对称的凹抛物线形分布,旋转动量主要集中在器壁和气柱处,径向速度呈不对称的双M形分布,且靠近气柱处的径向速度比器壁处的要大。上锥段中流体的轴向速度呈不规则的M型分布,轴向速度与流量不呈十分一致的关系,而是随着流量的增加,轴向速度有波动。上锥段中径向上的局部涡量呈不规则的双M形分布,靠近旋流腔壁处,负涡量的绝对值较大;零轴向速度包络面(LZVV)为一近似不规则的圆锥面,双切向入口中流体流量和介质黏度影响LZVV面的形状和分布位置。

In order to study the fluid flow behavior in hydrocyclone,the whole flow field of fluids in hydrocyclone with a bitangential inlet and twin cones was measured with the laser particle image velocimetry（PIV）,then the Tecplot was utilized to display the flow field,extract the tagential axial and radial velocities,calculate the vorticity,and plot the locus of zero vertical velocity（LZVV）.Distributional patterns of tangential and radial velocities in the swirl chamber of hydrocyclone as well as the axial velocity,local vorticity and locus of zero vertical velocity（LZVV） of fluids within the upper cone section under various flow conditions were investigated.The results show that in the swirl chamber,the tangential velocity of fluid is distributed in a shape of centrally symmetrical concave parabola,and its rotary momentum is mainly concentrated on the wall and at gas column,while the radial velocity shows an asymmetric ＂double-M-shaped＂ distribution with a velocity at the gas column bigger than that on the wall.In the upper cone section,the axial velocity of fluid has an irregular ＂M-shaped＂ distribution,inconsistent with the flow rate but fluctuating with its increase,the local vorticity of fluid shows an irregular ＂double-M-shaped＂ distribution with a absolute value of the negative vorticity getting larger near to the swirl chamber wall,the LZVV is somehow approximately like an irregular conical surface,and both the shape and the distributional locality of the LZVV are affected by the fluid flow rate within the bitangential inlet and by viscosity of the medium used.