Non-Newtonian fluid flow between a pair of rotating cylinders with unequal size rolls and equal speed of rolls is studied theoretically for the Bingham plastic fluid model at the isothermal condition, using the bipolar cylindrical coordinates in which the boundary conditions can be prescribed exactly. A theoretical analysis of the velocity, pressure and shear stress distribution is given by solving the continuity equation and equations of motion applying the lubrication approximation.
The pressure increases monotonically with the increase of the roll radius ration and the film thickness increases with the decrease of the flow behavior index for a constant entrance coordinate. Meanwhile, the velocity profile varies with the roll radius for the nip distance of 0.01 ㎝ in the ase that the roll radius is less than 0.6 ㎝. The limiting roll size is 0.6 ㎝ and the incidence angle at the entrance point is about 8.6∼9.0 degree. the opwer consumption per unit volumetric flow rate increases with increasing the roll wpeed and the roll diameter, and with decreasing the nip distance.