(5)
where R s is the radius of the screw,R b is the inner diameter of the barrel, andΩ is the relative speed of the screw rotation. Notice that the screw is stationary, and the barrel is considered to rotate at the relative screw speed, Ω . Assuming that the pressure gradient is constant within the calculation element, the integration of Eqs. (2) and (3) is performed under the boundary conditions of Eqs. (4) and (5) to obtain the flow velocities given below.
The fluid velocity in the θ -direction is given as