Discovered functions for Shear Stress and Pressure Drop of Linear Low Density Polyethylene Using Genetic programming

The esti mati on of the functions that descri be the shear stress and the pressure drop across the short orifice die as a function of shear rate at different mean pressures for linear-low-density polyethylene copolymer (LLDPE) at 190oC is obtained using Genetic Programmi ng (GP) . The GP has been running base d on e xpe rimental data in two cases; shear stress and pressure drop at differe nt mean pressures to produce shear stress and pressure drop for e ach target mean pressure. The shear rate and mean pressure of linear-low-density polyethylene copolymer have been use d as input variables to find the discove re d functions . The experi mental, cal culate d and pre dicte d shear stress and pressure drop are compare d. The discovere d function shows a good match to the e xpe rime ntal data. We find that the GP techni que is a good ne w me chanism of dete rmination of the shear stress and the pressure drop linear-low-density polyethylene copolymer. Index Term-Geneti c Programming, pressure drop , shear stress , shear rate, linearlowdensity polyethylene copolymer