Numerical modelling and experimental verification of blown film processing

Modeling of the film blowing process by using variational principles

“…This can explain why the bubble wants to avoid such a situation and an unstable bubble formation may be a way of doing it. This example suggests that the critical points mentioned above may be connected with bubble instabilities widely described in literature [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] but, of course, more detailed investigation is needed to support such an idea.…”

“…It is interesting to note that instabilities have been experimentally identified for BUR close to 1 [5]. According to the model prediction, infinite force is needed to achieve such a state.…”

“…The crucial factor, which determines physical and mechanical properties of the film, including the tensile strength, tear resistance, heat seal and optical characteristics, has been found to be the amount of frozen-in stresses in the film at the freeze-line [1][2][3]. Moreover, the occurrence of the wide range of bubble instabilities during film blowing process significantly reduces the processing window [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Although the film blowing process has been widely investigated experimentally as well as theoretically [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43],…”

Application of variational principles in modeling of the film blowing process for high stalk bubbles

“…The only difference is definition of pJ(p J ) value, where the additional parameter E appears in case of Eqs. (5) and (6). In the next section, main attention is paid to the high stalk bubble, i.e.…”

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

“…The first film blowing model was developed in 1970 by Pearson and Petrie [4][5][6] utilizing isothermal processing conditions, a Newtonian model as the constitutive equation, assuming the film as a thin shell in tension and neglecting the effect of inertia, surface tension, air drag, and gravity. 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].…”