Flow pattern prediction in polyurethane foaming process by numerical analysis

摘要

A foam flow model for flow pattern predictions in polyurethane foaming in a thin cavity has been developed. The model was based on a Hele-Shaw approximation that considers the flow caused by foam expansion due to bubble generation. The flow pattern was calculated from the initial volumetric shape of the poured polyurethane reaction mixture without need for a detailed study of the foaming properties. Numerical flow analysis was carried out by the finite element method based on controlled volume. The predictions were in good agreement with experimental results that were measured on panel type molds and a refrigerator. This model was appropriate for the rapid determination of the pouring position, the poured volume and the air vent position.