LDV Diagnosis of The Flow Field in a Hydrocyclone
with a Single Cylinder and a Cone
Lu Yaojun      Shen  Xiong     Zhou   Lixing
(Department of Engineering Mechanics, Tsinghua University, Beijing 100084)

Abstract: The detailed flow field in a liquid-liquid hydrocyclone with a single cylinder and a cone has been measured using a 2-D LDV. The effect of different flow parameters, such as overflow ratio, pressure ratio, flow rate and air core on the flow field has been studied. The results show that the tangential velocity profile
s have a typical Rankine vortex structure: solid body-body rotation plus free vortex, and change slightly along the axial directon. This indicates that the adopted cone angle is suitable. Since this geometrical configuration has a large hydraulic diameter, all the tangential velocities are kept in a low level, so the separation performance is not good enough. The double peaks in tangential velocity profiles are not observed. As for the axial velocity, both the upward and downward axial velocities in the near-axis and near-wall regions are in a low level,especially near the inlet region. This is helpful for increasing the resident time and decreasing the pressure drop. The Reynolds stresses have higher values near the axis and near the wall. The axial normal Reynolds stress is greater than the tangential one in the upstream region and is smaller than the tangentialone in the downstream region. So the turbulence in the hydrocyclone is anisotropic. Compared with the effect of other flow parameters, the effect of the flow rate is greatest both in its range and extent. The influence of other factors is limited only in the near-axis region.
Keywords: hydrocyclone, oil-water separation,LDV diagnostics.