Relations between y+ Value and Adaptive Computation Result for Manufacturing Bottles

Energy-saving and faster manufacturing techniques are essential requirements for the ideal production of polyethylene terephthalate (PET) bottles. The establishment of accurate calculation skills strengthens a quality working environment for improving manufacturing technology. We applied the adaptive finite element method and calculated the time-dependent SST (shear stress transport), k-ω, k-ε and LES (large eddy simulation) models to predict the airflow field around the PET bottles in a heating box. The computation of the flow field was performed using software COMSOL 5.5 (COMSOL Inc., Palo Alto, CA). The experimental data are acquired to compare with simulation results in terms of calculation accuracy. Computational fluid dynamics (CFD) results showed that error for the velocity and pressure of the flow field at specific positions in the vicinity of the preform was satisfied. The error estimation on the main physical quantity helps calculate other physical quantities. The variation trend of y+ values near the bottle surface had an identical trend alongside the gird concentration trend during the adaptive computation process. This study reveals that the outcome of the adaptive computation method and its underlying theories satisfy the physical requirements in this case.