The 3 D non isothermal flow of non Newtonian viscous polymer melt in a co rotating twin screw extruder is modeled. The distributions of the velocity, temperature, pressure and the viscous dissipation in the fl...The 3 D non isothermal flow of non Newtonian viscous polymer melt in a co rotating twin screw extruder is modeled. The distributions of the velocity, temperature, pressure and the viscous dissipation in the flow domain are presented by using a fluid dynamics analysis package (Polyflow). The numerical results show that the temperatures are high in the intermeshing region and on the screw surface, the maximum pressure and the minimum pressure occur in the intermeshing region, and the flow rate is almost proportional to the screw speed.展开更多
Aim To discuss the existence of periodic solutions for the first boundary problem of incompressible non Newtonian fluids, a problem arising from polymer processing and concerned with the first initial boundary valu...Aim To discuss the existence of periodic solutions for the first boundary problem of incompressible non Newtonian fluids, a problem arising from polymer processing and concerned with the first initial boundary value problem of nonstationary flow of the non Newtonian viscous incompressible fluids through slit dice. Methods The monotone operator theory and Schauders fixed point theorem were used. Results and Conclusion The existence theorem of periodic solutions of a Dirichlet problem is proved under reasonable conditions.展开更多
A new hybrid finite volume method for the numerical simulation of steady flow of Oldroyd B fluid is presented. Our study has two purposes: one is to develop a new hybrid finite volume method to simulate the flow of Ol...A new hybrid finite volume method for the numerical simulation of steady flow of Oldroyd B fluid is presented. Our study has two purposes: one is to develop a new hybrid finite volume method to simulate the flow of Oldroyd B fluid and the other is to test the method in an attempt to simulate the planar 4∶1 contraction flows of such fluid. The main features of this method are that the technique of Chorin's pseudo compressibility is used to solve the steady incompressible continuity equation and momentum equations and the streamline upwinding approach is used to discretize the constitutive equations. The method is applied to a sudden contractions viscoelastic flow problem for a range of Weissenberg numbers. Numerical experiments suggest that the results of the present numerical method be in good qualitative agreement with existing experimental results.展开更多
This paper provides a mathematical model and numerical method for predicting the velocity and temperature fields in the mud flows at the surface of a PDC (Polycrystalline Diamond Compact) bit. A 81/2' ( 21 59cm...This paper provides a mathematical model and numerical method for predicting the velocity and temperature fields in the mud flows at the surface of a PDC (Polycrystalline Diamond Compact) bit. A 81/2' ( 21 59cm ) crown type PDC R bit is used as an example. The complex configuration of the PDC bit surface is resolved numerically using body fitting coordinates and the cutters are simplified as drag elements in the momentum equations and as heat source in the energy equation. The finite volume method is used to discretize the momentum and energy equations for the non Newtonian flow. The numerical results effectively predict the flow structure and temperature field which can be used to design and optimize the PDC bit.展开更多
文摘The 3 D non isothermal flow of non Newtonian viscous polymer melt in a co rotating twin screw extruder is modeled. The distributions of the velocity, temperature, pressure and the viscous dissipation in the flow domain are presented by using a fluid dynamics analysis package (Polyflow). The numerical results show that the temperatures are high in the intermeshing region and on the screw surface, the maximum pressure and the minimum pressure occur in the intermeshing region, and the flow rate is almost proportional to the screw speed.
文摘Aim To discuss the existence of periodic solutions for the first boundary problem of incompressible non Newtonian fluids, a problem arising from polymer processing and concerned with the first initial boundary value problem of nonstationary flow of the non Newtonian viscous incompressible fluids through slit dice. Methods The monotone operator theory and Schauders fixed point theorem were used. Results and Conclusion The existence theorem of periodic solutions of a Dirichlet problem is proved under reasonable conditions.
文摘A new hybrid finite volume method for the numerical simulation of steady flow of Oldroyd B fluid is presented. Our study has two purposes: one is to develop a new hybrid finite volume method to simulate the flow of Oldroyd B fluid and the other is to test the method in an attempt to simulate the planar 4∶1 contraction flows of such fluid. The main features of this method are that the technique of Chorin's pseudo compressibility is used to solve the steady incompressible continuity equation and momentum equations and the streamline upwinding approach is used to discretize the constitutive equations. The method is applied to a sudden contractions viscoelastic flow problem for a range of Weissenberg numbers. Numerical experiments suggest that the results of the present numerical method be in good qualitative agreement with existing experimental results.
文摘This paper provides a mathematical model and numerical method for predicting the velocity and temperature fields in the mud flows at the surface of a PDC (Polycrystalline Diamond Compact) bit. A 81/2' ( 21 59cm ) crown type PDC R bit is used as an example. The complex configuration of the PDC bit surface is resolved numerically using body fitting coordinates and the cutters are simplified as drag elements in the momentum equations and as heat source in the energy equation. The finite volume method is used to discretize the momentum and energy equations for the non Newtonian flow. The numerical results effectively predict the flow structure and temperature field which can be used to design and optimize the PDC bit.
