The systematical design of plastic spiral extrusion dies and validation of the design methodology by CFD analyses

Abstract

A spiral mandrel die fed by coat-hanger type distributors was designed systematically in the present study. At the first stage, the preliminary design of the distributor was completed by use of analytical approach. At the second stage, the performance of the preliminary distributor design was evaluated based on the analogy between fluid flow systems and electrical network systems. Computational Fluid Dynamics (CFD) Simulations were performed for the preliminary distributor design. With respect to the pressure drop and velocity distribution at the die exit, it is confirmed that there is a good agreement between the results of electrical network analogy and CFD analysis. At the third stage, the geometric parameters of the coat-hanger die were optimized with the aid of reverse engineering approach in electrical network analogy in order to obtain uniform velocity distribution at the distributor exit. A CFD analysis was carried out for the designed distributor. The geometric parameters of the spiral mandrel die were optimized using an analytical approach from literature [13]. A CFD simulation was performed for the designed spiral mandrel die and it is shown that a quitely uniform velocity distribution is obtained at the die exit. Aforementioned analytical approach showed a satisfying performance in terms of estimating pressure drop and obtaining balanced flow at the die exit.