Macroscopic and mesoscopic simulation of viscoelastic free surface flow in gas‐assisted injection moulding process

Abstract

In this work, an improved simple coupled level-set and volume of fluid (S-CLSVOF) method is proposed to trace the moving interfaces in gas assisted injection moulding (GAIM) process based on the viscoelastic FENE-P model. Firstly, the Kreisselmeier-Steinhauser (KS) function constructed by means of Boolean operations is adopted as the shape level set (LS) function to precisely represent the complex mould cavities. Then, the benchmark problem of two-dimensional deformation is used to verify the ability of the S-CLSVOF method for capturing the moving interfaces. The stress birefringence is calculated and compared with the experiment result. Finally, the proposed method is further applied to the mould filling and gas penetration processes in GAIM. The macroscopic bubble appearance, temperature distribution, and the behaviour of the mesoscopic molecular orientation are shown and analyzed in detail. Due to the complexity of the gas-liquid interaction, the phenomenon of asymmetrical gas flow is clearly observed in the gas penetration process. The influences of the macroscopic parameters on the macroscopic gas flows and mesoscopic molecular orientation are also discussed, such as insert positions, melt temperatures, and gas delay time. The numerical results illustrate that the coupled method can be applied to the multiscale numerical simulation of viscoelastic flows with complex free surfaces and provide significant guidance for the GAIM process.

Numerical Simulation and Experimental Study the Effects of Process Parameters on Filament Morphology and Mechanical Properties of FDM 3D Printed PLA/GNPs Nanocomposite

“… is the rate of deformation tensor. is the smoothed Heaviside function that ensure the controlling equations can be solved in the whole computational domain [ 45 ]. is a parameter related to the thickness of interface, in this work, x [ 46 ].…”

Parameter identification of transport PDE/nonlinear ODE cascade model for polymer extrusion with varying die gap

“…Molten polymers exhibit complex viscoelastic behaviour that is difficult to model. [ 23–29 ] An appropriate viscoelastic model depends on the polymer type, flow problem configuration, and precision required. [ 30 ] In addition, the die gap is varied in most practical situations in the industry during die gap programming.…”