Angle Inclination Effect on Vortex Breakdown Zone in Rotating Flow Inside a Vertical Conical Container

This study presents a numerical investigation of the swirling flow inside a vertical conical container.The container is filled with liquid metal (Prandtl number, Pr=0.015), with the upper disc rotating at a fixed angular velocity while the bottom disc remains stationary.The sidewall of the container is rigid and inclined.In such a configuration, a phenomenon called vortex breakdown can occur, acting like a stagnation point against the axial flow pattern; the purpose of this study is to illustrate how the inclination of the cylinder's sidewall can affect the vortex breakdown and their emergence and suppression, The study encompasses a range of Reynolds numbers (1000≤Re≤2500) and various aspect ratios (1≤H/R≤2.4)where three different angles of inclination (α=5°, 10°, and 15°) are considered.The results are obtained by resolving numerically the governing equations using the finite volume technique.Our findings indicate that, for a given Reynolds number (Re=2000) and aspect ratios in the range of 1.2≤H/R≤1.6,the inclination of the sidewall leads to an earlier occurrence of vortex breakdown.On the other hand, for aspect ratios in the range of 1.8≤H/R≤2.2,the inclination of the sidewall results in the suppression of vortex breakdown.Furthermore, we have observed that the critical Reynolds number (Re_c) at which vortex at which vortex breakdown occurs for aspect ratios of A=H/R=1.4,1.8, and 2.2 increases with the increasing angle of inclination α.