The effect of swirl flow in an immersion nozzle on the heat and fluid flow in a billet continuous casting mold

Abstract

A numerical analysis and a water model study of the mold region of a billet continuous caster was performed with a novel injection concept using swirling flow in the pouring tube, to control the heat and mass transfer in the continuous casting mold. The following results were found: A weak impinging flow can be observed near the corner of the mold wall, which results in the promotion of uniform heat and mass transfer all around across the plane, particularly at the casting corner. An upward flow directed from the vicinity of the nozzle outlet to the meniscus can be observed near the corner of the upper part of the mold, which leads to the active heat and mass transfer into the meniscus. A uniform velocity and heat distribution can be obtained within a short distance of 200 mm downward from the outlet of the nozzle. Quite different mold flow patterns are observed between the divergent and straight immersion nozzles. Heat and mass transport in the mold using the divergent nozzle is much more reasonable than that using the straight nozzle.

Development of Flow Field and Temperature Distribution during Changing Divergent Angle of the Nozzle When Using Swirl Flow in a Square Continuous Casting Billet Mould

“…The assumptions made, general transport equations and boundary conditions are specified below. The model is an extension of previous work, [1][2][3][4][5][6][7] where details regarding the transport and turbulence equations can be found.…”

“…[1][2][3][4][5][6][7] Literature review showed that a systematic study of changes in the divergent angle in the immersion nozzle for continuous casting moulds had not been carried out. Therefore, in the present work we aim to investigate the development of flow field and temperature distribution inside the mould and on the meniscus while changing the divergent angle of the immersion nozzle.…”

“…One way of changing the flow in a nozzle is to use a swirl flow created by a swirl blade. Swirl flow phenomena have been extensively studied by Yokoya et al [1][2][3][4][5][6][7] In the earlier research it was shown that swirl flow helps to control the flow pattern in the mould. In addition, the use of swirl flow enhances heat and mass transfer and helps the superheat in melt to dissipate.…”

“…Literature review of several papers by Yokoya et al [1][2][3][4][5][6][7] showed that previous research had focused on applying swirl flow to billet continuous casting (CC) moulds considering only specific divergent angle in the immersion nozzle outlet. Yokoya et al showed that:…”

A First Attempt to Implement a Swirl Blade in Production of Ingots

“…This swirl flow phenomena have extensively been studied by Yokoya and co-workers. [6][7][8][9][10][11][12] Their results have shown that swirl flow helps to control the flow pattern in the mould. Furthermore, that the use of swirl flow in the immersion nozzle enhances the heat and mass transfer in the mould, which in turn helps the superheat in the melt to dissipate.…”