EXTENSION OF 21 2-D CONTROL-VOLUME METHODS FOR TRANSVERSE FLOW AT SPRUES, GATES AND JUNCTIONS/

Commercial injection mold filling simulations use the lubrication appr oximation to model pressure and temperature during flow. This approxim ation is valid when flow streamlines ale parallel to a cavity surface, such as when the cavity thickness is much smaller than the flow lengt h. Yet this approximation may not be valid in complex cavities where t he streamlines ale not parallel. Flow through junctions, gates and spr ues ale always accompanied by a velocity component transverse to the m old surface which is not included in the model. Neglecting transverse flow through use of the lubrication approximation can result in anomal ous changes in bulk mean temperature, filling patterns, and molecular and fiber orientation. This paper presents a mass balance algorithm fo r approximating transverse flow through gates, sprues and junctions. T his new algorithm is presently suitable for only relatively simple geo metries. Future work will attempt to make a similar algorithm for tran sverse flow through complex mold shapes with negligible penalty in add itional computational run time.