Numerical Modeling of Thermal Flows in Entrance Channels for Polymer Extrusion: A Parametric Study

Abstract

Flow distribution channels in extrusion dies are typically designed to assure uniform fluid velocity, pressure and temperature in the outlets. To ensure this uniformity, it is desirable to have the fluid melt to reach a steady state temperature in the entrance channel before entering the die body. This paper numerically investigates the temperature distribution of the fluid melt in the entrance channel. Analytical solutions of the velocity and finite element solutions of temperature distribution in Poiseuille flows of polypropylene melt with the Casson rheology model were derived and presented. In the velocity solution, the critical point that separates the core and the remaining parts in the flow was calculated by using the inlet flow rate and the yield stress in the Casson model. The velocity distribution was then substituted into the convective heat equation for temperature distribution simulations. A finite difference scheme was used to obtain the temperature distribution profiles along the flow direction in a parallel-plate, while the finite element model was used to model the flow temperature in circular tubes. The main outcome is the parametric analyses of the effect of various parameters such as radius, wall temperature, inlet temperature, and pressure drop to the optimal length of the channels required for the flow temperature to reach the steady state.

A Multi-Rheology Design Method of Sheeting Polymer Extrusion Dies Based on Flow Network and the Winter–Fritz Design Equation

“…Most Poiseuille and shear-rate relations given in the literature have limited capacity to only one (generalized) non-Newtonian fluid, such as the power-law fluid [1,20,21].…”

An Iterative Approach for the Parameter Estimation of Shear-Rate and Temperature-Dependent Rheological Models for Polymeric Liquids

“…Experimental measurements of polymeric liquids (solution and melt) are routinely carried out to obtain the necessary data on their rheological properties. Then, various numerical methods were used to find a suitable set of parameters for the rheology model to facilitate efficient flow simulations [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ].…”

Testing the PTT Rheological Model for Extrusion of Virgin and Composite Materials in View of Enhanced Conductivity and Mechanical Recycling Potential

“…Extrusion, which is a material forming operation under melt conditions, is widely used in industrial sectors, including polymeric applications [1][2][3][4][5]. Plastic profiles and in general polymer materials are applied today on a large scale in several industrial fields, including the medical and construction sector [6][7][8][9][10]. More recently, there is also interest to use plastics for heat exchangers [11,12].…”

“…In addition, a similar varying trend is noted for 𝜉 although with a lower value of the determination factor 𝑅 . The associated equations are: 𝜀(𝑥) = 0.31 + 2.90𝑥 and 𝜉(𝑥) = 0.22 + 3.69𝑥(9)…”