axisymmetric model of two rotating disks cavity

liaolingling

It is about a hydroviscous speed drive,simply like a wet clutch.let's just talk about of one set of its friction disks.

The drive friction disk ,with a diameter of 270mm,rotates with the motor at1500rpm. the cavity between two disks is full of oil that transmittes torque from the drive disk to the driven one.Through the hydraulic viscous shear stress,the driven disk could be forced to rotate at a certain speed which is closely related to the thickniss of the oil film between two friction disks.

In my case,the oil film is 0.4mm thick,and the driven disk has a rotational speed of 1200rpm,with its inside diameter of 170mm,outside diameter of 270mm.

the oil property : density:872kg/m3,viscosity:24mm2/s,(50oC) .The oil flows into the cavity between two disks through the center of the driven disk, at a pressure of 2bar, a flow rate of 120L/min, temperature of 30 oC, and the flow is out radially of the cavity with a outflow pressure about 0 par. Beside ,the two disks have sustained a mount of squeeze force so that the oil film won¡¯t fail. Neglecting the thickniss of two disks, I need to simply calculate the pressure field and temperature field of the cavity fluid . I have to take care that the viscosity of the oil may be changed by the shear stress, thus the oil may change from Newton fluid into Non-Newton fluid . Modeling in gambit is not difficult,but I have Some trouble in setting boundary conditions in fluent. I have tried several models but works bad. Can you help me ?