Application of Silicone Fluid Rheogoniometer Measurements to Despin Moment Studies in a Spinning and Coning Cylinder.

摘要

A Weissenberg rheogoniometer was used to measure the viscosity and normal stress for a series of high viscosity silicone fluids that were used in despin moment studies of a spinning and coning cylinder. The measurements indicated viscosity shear thinning and significant normal stress at high shear rates. The effect of this non-Newtonian fluid behavior on despin moment was then investigated. Two simple viscoelastic fluid constitutive models, a differential and second order fluid, were evaluated using the fluid rheology data. The differential model fit the fluid rheology data better than the second order fluid, which does not predict shear thinning. Derived differential model parameters were used to calculate theoretical despin moments for the silicone fluids in an infinitely long cylinder. The despin moments for the higher viscosity fluids were found to be significantly higher than those predicted for Newtonian fluids; however, they compared qualitatively with despin moment test results, which were also significantly higher. From this analysis, it appears that the differences between the despin moment test results for the higher viscosity silicone fluids and theoretical predictions for Newtonian fluids can be attributed to the viscoelastic properties of the silicone fluids.