Prediction of first normal stress difference during extrusion flow of tube compound;

The melt elasticity of PP filled with CaCO3 of nano-particles or micron particles or their assembling was studied by capillary rheometry measuring the values of first normal stress difference(N1) and extrudate swell(B) of the systems.

By processing the datas with statistics, the standard values of the viscosity and the first normal stress difference of the certified reference material in various steady shear rate were defined and the related expanded uncertainties of which were given.

Combining the theory of continuous medium mechanics with the theory of rheological measure, this paper studied the dynamic extrusion process of polymer melt under superimposed vibration and established the mathematical formula of primary normal stress difference of polymer melt under vibration force field.

The primary normal stress difference at the wall of the capillary under the vibration force field was calculated besed on the set-up representative law for the polymer elastic behavior under the vibration force field.

The physical experiment on hydraulic fracturing propagation in laboratory showed that the penetration of hydraulic fracture into the salutatory barrier mainly depended on the normal stress difference between salutatory barrier and pay zone.

he flow of a power-law fluid flowing through an enlarged conical channel wasstudied, thus regressive relationships between die swell ratio B and normal stress difference N were obtained.

Results include secondary flow,axial velocity and normal stress difference,which are affected by the Weissenberg number and Reynolds number.