Papers by Author: Lian Cheng Ren

Abstract: A magneto-rheological (MR) fan clutch is a device that transmits torque by the shear stress of the MR fluids. In this paper, Bingham model is used to describe the constitutive characteristics of MR fluids subject to an applied magnetic field. The operational principle of the MR clutch is introduced. The torque transmitted by MR fluids is analyzed to compute the torque transmission ability in the MR clutch. The results show that with the increase of the applied magnetic field, the torque developed by MR fluids goes up rapidly.

Abstract: On the base of numerical simulation and theoretical analysis, the flow field of a conventional single-tangential-inlet Hydrocyclone and a newly put forward axial-symmetry double-tangential-inlet hydrocyclone were contrasted. The study shows that the inlet structure of the Hydrocylone has a great influence on the radial velocity of the flow field in the hydrocyclone and that the radial velocity in the hydrocyclone with single-tangential-inlet is not symmetry about the axis of the hydrocyclone; and on the other hand the radial velocity in the hydrocyclone with axial-symmetry double-tangential-inlet is symmetry about the axis of the hydrocyclone. The magnitude of the radial velocity of the flow in the hydrocyclone with single-tangential-inlet is greater than that in the hydrocyclone with axial-symmetry double-tangential-inlet hydrocyclone, which means the hydrocyclone with axial-symmetry double-tangential-inlet has greater capability than the rival one with single-tangential inlet. The symmetry about the axis of the hydrocyclone of the radial velocity means the radial velocities in the place where the radio is the same are constant, which means the hydrocyclone has a great separation efficiency. The conclusion is that changing the conventional hydrocyclone into the one with axial-symmetry double-tangential-inlet structure can offer greater separation capability and efficiency.

Abstract: Natural gas downhole choke process inlet is high temperature and high pressure. Usually it can achieves 10~30MPa, while it will be higher in high pressure drilling well. It is installing thousands of meters underground. It is difficult carrying on field test during working process. These special situations make the choke outlet flow being complex, which includes expansion wave, compression wave, and energy transformation. The physical experiment is difficult. To be more accurately analyzing the compressible viscous turbulent motion of downhole choke internal flow field, this article uses RNG − model for three dimensional numerical simulation. It analyzes the result of flow field streamlines, velocity, Mach number, pressure, and temperature distribution. It analyzes the influence on hydrate formation of choke working process. Numerical calculation can provide useful reference for the prevention of natural gas hydrate formation and optimization design of downhole choke.