Thermal state of an incompressible pseudo-plastic fluid and Nusselt number at the interface fluid–die wall

An experimental and numerical study was made of the steady laminar convective heat transfer to polyethylene Dowlex 2042E described by the Cross model flowing through an extrusion die. The inverse heat transfer problem is formulated to reconstruct the thermal history of the melted polymer in the channel die. Local Nusselt number distributions are presented for different flow rate and thermal boundary conditions. The effect of viscous dissipation combined with the flow rate on heat transfer is discussed. It is shown that an increasing flow rate leads to different Nusselt number and correlation is proposed to compute the heat transfer.