FLUID DYNAMICS IN HIGH-SPEED STRIP-CASTING METAL DELIVERY SYSTEMS

摘要

An experimental and theoretical investigation into fluid flow during high-speed strip casting of steel is presented. Experimental results from a full-scale water model of proposed metal delivery designs are utilized to evaluate the fluid dynamics component of a 2-D finite-difference numerical model of steel flow and heat transfer during solidification. Good agreement is achieved between predicted and measured flowrate-head relations and global flow patterns, for a range of slot-nozzle and extended pool geometries. In particular, the model correctly predicts the zones of recirculation observed in the extended pool design. The numerical model is then applied to determine the effects of heat transfer and solidification in metal delivery systems. For the extended pool geometry, solidification on the moving substrate is found to modify the flow pattern, resulting in a more uniform delivery of steel; moreover, the size of recirculation zones at the back wall is significantly reduced. For the range of conditions examined, the solidified shell thickness increases with increasing interfacial heat-transfer coefficient, but is relatively insensitive to steel superheat. The results are being applied to the design of metal delivery systems in the experimental programme of steel strip-casting trials on a horizontal, single-belt, Hazelett caster at BHP Central Research Laboratories.