Effect of Static Pressure on Melting

It is well know that melting occurs more rapidly if there is a positive pressure at the end of the transition zone. If Film B is considered to be large and if the pressure in the melt Film C is essentially zero at the trailing flight, a first order approximation of this pressure effect can be achieved by adding a pressure dissipation term to the rate of material loss in the y direction of the solid surface adjacent to the Film C  

Tadmor, Z. and Klein, I., Engineering Principles of Plasticating Extrusion, Van Nostrand Reinhold Company, New York, 1970 

Derezinski, S. J., Heat Transfer in Extruder Screws, SPE ANTEC Tech. Papers, 46, 83 (2000) 

This appendix contains the detaiied deveiopment for the veiocity and energy dissipation equations that are presented in Chapter 7. Fuii understanding of these deveiopments is not required for detaiied anaiysis and troubieshooting of the extrusion process. They are presented here for those who desire a deep understanding of the mathematics invoived with the screw rotation analysis. Some of the equations and figures are duplicated in this appendix for clarity. The nomenclature used here is consistent with that used earlier. The reader is directed to Chapters 1 and 7 for nomenclature. Flow rates can be easily calculated from the velocity equations. 

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