Non-Isothermal Simulation of the Film Blowing Process Using Multi-Mode Extended Pom-Pom Model

Abstract

Plastic films are largely produced using the film blowing process. Branched polymers such as LDPE are commonly used in this process to produce a variety of plastic films. In this study, recently developed eXtended Pom-Pom (XPP) model, which focuses on describing rheological behavior of branched polymers, is employed to analyze the non-isothermal flow in the film blowing process. Furthermore, the Nakamura equation for crystallization kinetics is employed to consider crystallization effects and improve prediction of the state of the stress in the film. Results of the numerical analysis show good agreement with the experimental values reported by Tas (1994) for the bubble shape and film velocity of the LDPE films. Predictions for the strain rates in machine and hoop directions which are critical for the estimation of the stress are also compared with the reported data and showed reasonably good agreement.

Modeling of Non-Isothermal Film Blowing Process for Polyolefines by Using Variational Principles

“…For the above presented parameters, the Figures 7-9 were generated. In more detail, the Zatloukal-Vlcek model predictions for the bubble shape (Figure 7), velocity ( Figure 8) and temperature profiles ( Figure 9) are compared with Tas's experimental data [16] together with theoretical predictions by Beaulne and Mitsoulis model [13] and Sarafrazi and Sharif [14] model. Based on the Figures 7-9 and Table 7, it is nicely visible that the predictions of the Zatloukal-Vlcek model are in very good agreement with the experimental data.…”

“…Comparison of the bubble shape between the Zatloukal-Vlcek model prediction [28], experimental data for the LDPE L8 taken from Tas´s Ph.D. thesis [16] and (a) the Beaulne and Mitsoulis model prediction [13]; (b) the Sarafrazi and Sharif model prediction [14]. [28], experimental data for the LDPE L8 taken from Tas´s Ph.D. thesis [16] and (a) the Beaulne and Mitsoulis model prediction [13]; (b) the Sarafrazi and Sharif model prediction [14].…”

“…The bubble is viewed as static flexible membrane having initially element length equal to dx (Figure 4), which is consequently deformed during the process by the internal load, p, and the take-up force, F ( Figure 5). After the bubble deformation the element length is given by the following equation [28,31]: (14) It has been shown in [28] that if the constant bubble compliance is assumed along the bubble, one can derive the analytical equation for the bubble shape satisfying the minimum-energy requirements by using variational principles. This model can be applied for description of different bubble types including high stalk bubbles [30].…”

Evaluation of variational principle based model for LDPE large scale film blowing process

“…This formulation became a basic idea for many researchers (see summarization provided in Muke et al [7]), such as Pearson and Gutteridge (1978) [8], Cao and Campbell (1990) [9], Liu et al (1995) [10], or in the last years e.g. Muslet and Kamal (2004) [11], Beaulne and Mitsoulis (2007) [12], Sarafrazi and Sharif (2008) [13]. It has been found that the challenging task in the complex film blowing modeling is low stability of the numerical schemes which limits utilization of such models for wide parametric study, which could allow deeper fundamental understanding of the film blowing process.…”

Investigation of heat transfer in 9-layer film blowing process by using variational principles

“…In spite of a rapid growth of a blown film coextrusion in the last decades, the number of experimental and modeling studies for this process is very limited [5][6][7][8][9][10][11][12] as well as number of works focused on modeling of heat transfer in film blowing process [8,[13][14][15][16][17][18][19][20]. In order to extend the knowledge in this area, the main goal of this work is to investigate effect of the heat transfer coefficient on temperature profile along the bubble for multi-layer film blowing process by using variational principles.…”