Effect of Wall Slip on the Flow in a Flat Die for Sheet Extrusion

Flow in a flat die with coat hanger type of manifold is simulated allowing slip on die walls. Flow in the same die was also simulated by enforcing the no-slip condition on the walls. With slip on the die walls, the pressure drop, shear rate, stress, as well as temperature increase in the die, all were smaller than the corresponding values with no-slip condition on the walls. For the case with slip on die walls, since the shear rate is smaller, the elongation rate in the die is found to be the dominant fraction of the total strain rate. Due to its high computational efficiency, the software employed in this work can be effectively used to design extrusion dies for fluids exhibiting slip on die walls.