Methods of CFD Modelling of Twin-Screw Pumps for Non-Newtonian Materials

Abstract

The twin-screw pump is designed for pumping highly viscous materials in the food industry. Rheological characteristics of materials are important in the specification of design parameters of screw pumps. Analysis of flow in the twin-screw pumps with definition of non-newtonian materials can be made by numerical modelling. CFD generally oriented software ANSYS Fluent and ANSYS Polyflow has been used for modelling. In this study those software’s (ANSYS Fluent and ANSYS Polyflow) were defined for solution of flow in the twin-screw pumps. Results were compared for the same boundary conditions on the inlet and outlet of the 3D model. For definition of the viscosity were used the Nonnewtonian power law. Parameters as consistency coefficient and flow exponent for Nonnewtonian power law were analysed by software ANSYS Fluent and ANSYS Polyflow. Postprocessing form ANSYS Fluent and ANSYS Polyflow were made by contours of field and by graphs.

Investigation of effect of the profile of screw flight on chocolate flow in 3D printing using an improved lattice Boltzmann method

“…where ∂P/∂x is the pressure gradient, H is the distance between two parallel plates and y describes the distance from the center to some point. When ⊗ = 0, the fluids will become Newtonian type according to Eqn (12), then the velocity distribution of Eqn (24) also changes. In Eqn (12), ⊘ 0 and ⊘ ∞ stand for the viscosities of the cases of zero and infinity shear rates.…”

“…When ⊗ = 0, the fluids will become Newtonian type according to Eqn (12), then the velocity distribution of Eqn (24) also changes. In Eqn (12), ⊘ 0 and ⊘ ∞ stand for the viscosities of the cases of zero and infinity shear rates. When ⊘ ∞ /⊘ 0 =1, the fluids will be Newtonian type.…”

“…When conducting the flow dynamic analysis, the non‐Newtonian behavior will prohibit commercial software, such as fluent (Ansys Inc., Canonsburg, PA, USA). If the common software is used for the analysis, secondary development is essential, whereas the process is difficult, uncertain and error‐prone 12‐14 . The lattice Boltzmann method (LBM) achieves the flow dynamic analysis with the programming.…”

“…If the common software is used for the analysis, secondary development is essential, whereas the process is difficult, uncertain and error-prone. [12][13][14] The lattice Boltzmann method (LBM) achieves the flow dynamic analysis with the programming. The physical process and the related mathematical functions are easy to understand, and complex integration or a differential process is avoided.…”