Novel cooling channel shapes in pressure die casting

The pressure die casting involves die designs incorporating cooling channel s positioned to facilitate the controlled extraction of energy from a solid ifying casting. It is now known that subcooled nucleate boiling can occur i n cooling channels and this paper is concerned with novel cooling channel s hapes that are optimized to promote and enhance this boiling and thus reduc e casting times. Shape sensitivity analysis is applied to a boundary elemen t model using the material derivative adjoint variable technique. Mesh node positions on the cooling channels are used as the design parameters. The s ensitivities are used in a conjugate gradient non-linear optimization routi ne. It is shown that with this approach cooling channels can be designed to maximize boiling heat transfer whilst at the same time allow some degree o f control of spatial temperature variation over the die cavity surface. Sim ulation and experimental results are presented for a traditional die and an optimized die. A 60 per cent reduction in cycle time is achieved with the optimized die. Copyright (C) 2001 John Wiley & Sons, Ltd.