1994 Volume 80 Issue 4 Pages 312-317
Application of the pinch force to the separation of inclusion particles from liquid steel flowing in a rectangular pipe was investigated theoretically. By impressing an electrical current in a liquid metal along the axis of the pipe, the metal will receive a pinch force and electrically nonconductive particles suspended in the metal will be squeezed out by this force. In the case of rectangular pipe, the pinch force is concentrated near the corner of the pipe at high frequencies, and as a result secondary flows may be generated in the cross section of the pipe. These flows will affect the particle-separation efficiency.
Numerical calculations were made to obtain the pinch force, fluid flow and particle concentration. In the quarter section of the pipe, two recirculating flows were generated and their maximum velocity increased with increasing x1/ δ. Pipe Reynolds number, Re(=2x1w/ν), decreased rapidly after x1/δ exceeded a critical value which changed with C1(=μeIrms2/ρν2). The particle-separation efficiency, η, was a function of (C1DR2/Re)Z while the secondary flows are negligible. The value of η was found to increase with increasing x1/δ because of the development of the secondary flows. This result is a contrast to the case of circular pipe investigated in the previous study.
