Sharif Digital Repository

This thesis was conducted both numerically and experimentally. In the experimental investigations aqueous solutions of high molecular weight Carboxymethylcellulose (CMC) was used. The experimental set-up was composed of a glass syringe, and a piston which can easily move through the syringe. Different die with aspect ratio ranging from 5.25 to 28.8 can be attached to the syringe. The syringe then is filled with the CMC solution with different weight fractions. Then using a force exerting on the piston, the solution comes out of the die and exiting velocity was calculated from weight of CMC solution that exit from die in a definite time. High quality photographs were taken from extrudate...