HEAT TRANSFER TO POLYMER MELTS FLOWING THROUGH NARROW CHANNELS.

In the reported theoretical study, programs have been developed to solve heat transfer problems in different flow geometries with various boundary conditions to correspond to actual flows in polymer extrusion. Constant wall temperature cases have been treated. The programs, however, can be easily adapted to constant heat flux at the walls (for example, adiabatic walls when heat flux equals zero). Care must be taken in choosing the step sizes in the finite differences network, so as to obtain accurate values of temperature gradients, to prevent instability and to economize on computer time.