Bubble evolution in the titanium alloy melt under vertical centrifugal field

Abstract

The bubble evolution in the liquid titanium melt under vertical centrifugal field has been studied by the hydraulic experiment simulation. The bubble migration process in the simple and complex cavities, the bubble morphology, bubble dimensional size diversification under different mould rotational speed has been investigated. The results show that the mould wall has a blocking effect on the bubble migration. The bubble migration in the simple cavity deviates from the line between the bubble initial position and the rotation shaft of the casting mould. Also, the bubbles in the complex cavity gather, re-nucleate and form new big ones for the blocking effect of the complex geometry shape on the radial movement of the bubble. The shape of bubbles in both the simple and complex cavity during the migration process is not a perfect sphere, but an elliptical shape. The critical size of bubble released from the bubble generation chamber decreases with the increment of the mould rotational speed. The diameter of the gas bubbles in the simple cavity during the migration process become bigger and bigger for the pressure difference at different positions of the cavity in the vertical centrifugal field.