Performance Effects of a Round Bar Passing Through the Outlet of a Vortex Amplifier

Abstract

This paper considers the application of a vortex amplifier (VA) to the process of coating and surface heat treatment of a round bar. The advantage of using a vortex amplifier is not only a long maintenance free lifetime but also the ease with which the coating thickness or the heat treatment condition may be changed. Swirl burners offer many advantages in the surface heat treatment of round bars. The highly turbulent swirling flow generates uniform heat distribution and very high heat transfer coefficients which improve the quality of the surface being treated. The geometry of the swirl burner is such that very long bars may be treated using a relatively small burner, the bar being passed along the axis of the swirl burner. For coating applications, the round bar to be treated passes along the axis of the outlet of the vortex amplifier and the coating process is controlled by varying the control flow in the VA. Clearly the bar will have an effect on the performance. The effects of changing the diameter of the round bar are investigated. The effect of poor alignment of the round bar on the variations of supply pressure and control pressure is also considered. The flow patterns in the vortex chamber and the outlet were observed by means of cotton tufts. The internal flow patterns in the vortex chamber were observed using water model studies at a number of points on the vortex amplifier characteristic.