A FLOW MODEL FOR NON-NEWTONIAN LIQUIDS INSIDE A SLOT DIE

A one-dimensional flow model for non-Newtonian liquids inside a dual-c avity slot die is presented. The model is capable of analyzing slot di es of any cavity shape, cavity taper, slot-length variations, and slot -gap variations. The proposed model incorporates a truncated-power-law model for the viscosity of non-Newtonian liquids. According to flow m odels with power-law approximation for liquid viscosity, the distribut ion of a non-Newtonian liquid through a slot die depends on the slot R eynolds number only. With our model, we find that the zero shear visco sity and the relaxation time of a non-Newtonian liquid have large effe cts on its distribution. For non-Newtonian liquids which are expected to experience shear-thinning over portion of a slot die, it is conclud ed that a flow model with a truncated-power-law approximation for liqu id viscosity be used to predict the liquid distribution from the die.