Study On The Johnson-Segalman Fluid Of The Spurt Mechanism And The Effect Of Parameter In Pipe Flow

Non-Newtonian fluid have a wide range of applications in various fields, the search of Johnson-Segalman fluid flow characteristics on pipe flow has important significance, this paper takes Johnson Segalman fluid as the object of study with the analytical and numerical methods, the main research contents has the Johnson Segalman fluid flow characteristics on pipe flow and the effects of parameter, the parameter include the slip parameter a、the Weissenberg number We, and the ratio of viscosity Φ, the conclusions are as follops:(1) The spurt mechanism of the flow characteristics of the Johnson-Segalman:Because of the nonlinear relation of shear stress and the velocity gradient, under the effect of pressure gradient, the velocity gradient jumping own to the shear stress increasing or decreasing, which lead to the spurt phenomenon in the flow, and this phenomenon is stable in the shear stress reaches the critical value.(2) The influence of parameters on the constitutive relation:With the increasing of the ratio of viscosity, the constitutive relation turns Non-monotone into the monotonicity gradually; The greater the slip parameter, the critical value of shear stress is greater; The greater Weissenberg number is, the smaller the critical value of shear stress.(3) The influence of the velocity gradient which occurs jumping location:With the increase of the Weissenberg number, the jumping location moves from the wall surface to the center of the pipe diameter gradually; With the increase of the viscosity ratio, the process that the bottom jumping and the top jumping tends to wall surface gradually; With the increase of the slip parameter, jumping position moves from the center of pipe diameter to the wall.(4) The influence of velocity profile:In the case of certain parameter, comparing with the pressure gradient, the velocity profile is greater in the pressure decreasing. The velocity profile is larger with the increasing of Weissenberg number, and the velocity profile decrease with the increasing of slip parameters and the ratio of viscosity.(5) The influence of flow rate and pressure gradient relation:The corresponding pressure gradient when the sudden changes of flow rate which decreases with the increasing of Weissenberg number, and which increase with the increasing of silp parameter and the ratio of viscosity...