Temperature Rise in Die

Power is the work done per unit time, where work in the simplest sense is defined as 

Using this expression it is possible to make an approximation for the temperature rise of the fluid during extrusion through a die. If it is assumed that all the work is changed into shear heating and that all the heat is taken up evenly by the polymer, then the work done may be equated to the temperature rise in the polymer. 

Power = Heat required to change temperature = mass X specific heat x temperature rise 

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