THE EFFECT OF RESERVOIR GEOMETRY ON THE FLOW WITHIN CERAMIC TAPE CASTERS

The flow structure in the reservoir of a ceramic tape casting head is examined using a linear finite element formulation of the governing fl uid mechanical equations, written in terms of the streamfunction and v orticity. Streamline plots are presented for representative reservoir shapes and depth-to-width (aspect) ratios. Analysis predicts that the flow is characterised by an ever-present primary recirculation, adjace nt to the moving web, and that the size and number of secondary recirc ulations above the primary one depend upon both the aspect ratio of th e reservoir and the angle of inclination of the side walls. In particu lar, it is shown that the number of recirculations spanning the entire width of the reservoir increases at critical values of the aspect rat io, when eddies emanating from the upper corners merge together. The a nalysis also shows that for a given reservoir depth, it is possible to postpone the development of these secondary recirculations by 'openin g out' the casting head, i.e. making the sides further away from the v ertical, which may be a useful control mechanism for the design of suc h systems. (C) 1997 Elsevier Science Limited.