Calendering Newtonian model

A first model of the calender nip flow has been presented by ArdichviUi. Further on Gaskefl presented a more precise and well-known model. Both models are very simplified, which yields that the flow is Newtonian and isothermal, and they predict that the nip force is inversely proportional with the clearance. Since mbber materials show a shear thinning behavior Ardichvilli s model seems not to be very realistic. The purpose of this section is to present a calender nip flow model based on the power law. The model is stiU being considered isothermal. Such a model was first presented by McKelvey. ... 

Derive a model to predict flow and presssure distributions for the case of calendering a sheet of finite thickeness and Newtonian viscosity. 

Modeling the calendering process for Newtonian and shear thinning polymer melts. Using the RF method, Lopez and Osswald [5] modeled the calendering process for Newtonian and non-Newtonian polymer melts. They used the same dimensions and process conditions used by Agassant et al. [1], schematically depicted in Fig. 11.17. 

O.A. Estrada, I.D. Lopez-Gomez, and T.A. Osswald. Modeling the non-newtonian calendering process using a coupled flow and heat transfer radial basis functions collocation method. Journal of Polymer Technology, 2005. 

Nonsymmetric Calendering21 Derive the pressure distribution of a Newtonian fluid in a calender (a) with different size rolls but equal peripheral speed (b) with different speeds but equal-size rolls. Make the same simplifying assumptions that were made in the Gaskell model in Section 6.4. 

Example 15.1 The Significance of Normal Stresses We consider the calender geometry of Fig. 6.22 (shown here) and make the same simplifying assumptions as in Section 6.4, but instead of a Newtonian or Power Law model fluid, we assume a CEF model that exhibits normal stresses in viscometric flows. By accepting the lubrication approximation, we assume that locally we have a fully developed viscometric flow because there is only one velocity component vx, which is a function of only one spatial variable y. 

Calendering of Polymers The Newtonian Haskell Model A 0.2-m-diameter, 1-m-wide, equal-sized-roll calender operates at a speed of 50 cm/s. At a gap separation of 0.02 cm, it produces a 0.022-cm-thick film. Assuming a Newtonian viscosity of 104 poise, calculate in the last nip (a) the maximum pressure (b) the separating force and (c) estimate the mean temperature rise. 

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