摘要
The spinning flow of Boger fluids and the gravity-drawing extrusion flow of a Newtonianas well as a Boger fluid have been simulated by using the stream-line finite element method and thetechnique of matching the finite element solutions with those of one-dimensional spinning equations.The recoverable shear strain is proved not to be a basic parameter in characterising thespinning flow of Boger fluids.For Newtonian fluids this technique predicts the experimental jetshape accurately.For Boger fluids,the numerical simulation agrees with the experimental data of spin-ning flow reported by Sridhar et al.,but seems to give an insufficient swelling and over contractionof the jets when drawn by its own weight,compared with the experimental results of Trang andYeow.It implies that the Oldroyd-B model fitting the viscometric-flow data fails to describeaccurately the elasticity and extensional viscosity in the extrusion flow of Boger fluids with gravi-ty-drawing.
The spinning flow of Boger fluids and the gravity drawing extrusion flow of a Newtonian as well as a Boger fluid have been simulated by using the stream-line finite element method and the technique of matching the finite element solutions with those of one-dimensional spinning equations. The recoverable shear strain is proved not to be a basic parameter in characterising the spinning flow of Boger fluids. For Newtonian fluids this technique predicts the experimental jet shape accurately. For Boger fluids, the numerical simulation agrees with the experimental data of spinning flow reported by Sridhar et al., but seems to give an insufficient swelling and over contraction of the jets when drawn by its own weight, compared with the experimental results of Trang and Yeow. It implies that the Oldroyd-B model fitting the viscometric-flow data fails to describe accurately the elasticity and extensional viscosity in the extrusion flow of Boger fluids with gravity-drawing.
基金
Subject supported by the National Natural Science Foundation of China and Natural Science Foundation of Zhejiang Province
