Analysis of entrance pressure drop techniques for extensional viscosity determination

In this work, a novel (patent pending) orifice die design for precise extensional viscosity data determination from entrance pressure drop measurements has been developed and tested both theoretically (through Finite Element Analysis) and experimentally. It has been demonstrated that the proposed novel orifice die allows much more precise extensional viscosity measurements for polymer melts in comparison with conventional orifice dies. Moreover, it has been found that, for extensional strain hardening and extensional strain thinning polymer melts, the corrected Cogswell model and Binding/Gibson model should be preferred, respectively. Otherwise, the extensional viscosity determination can be rather erroneous.     

Finite element analysis of orifice-compensated multiple hole-entry worn hybrid journal bearing

This paper presents the analysis of a non-recessed worn hybrid journal bearing with orifice restrictors. Using Newton–Raphson method, FEM is used for solving Reynolds equation governing the flow of lubricant in the bearing clearance space. The bearing performance characteristics are presented for a wide range of wear depth. The results are computed for an orifice-compensated hole-entry configuration with uniform distribution of holes in the circumferential direction. The results show that the wear affects the bearing performance significantly and therefore, a due consideration of wear defect should be given for an accurate prediction of the bearing performance over a number of cycles.