Fluid Flow Modeling and Analysis of Low‐ and High‐Gravity Spiral Concentrators: Experimental and Analytical Approaches

An experimental evaluation of the flow field on two high‐gravity spiral concentrators is presented along with the analytical solutions. A digital depth gauge was used to measure the liquid level on the spiral troughs. The tracer particle trajectories and the free surface velocity of a spiral were determined with a high‐speed camera. An increase in the flow rate leads to an increase in the liquid depth and free surface velocity along the trough surface. Three full turns of the high gravity spiral concentrator are sufficient for achieving a stabilized flow. High‐gravity spirals show lower flow depths and free surface velocities but steeper depths on the outer trough zone than low‐gravity spirals. Higher flow depths contribute to larger circulation zones, which eventually help in greater separation of heavier minerals from gangue particles. The water flow depth and free surface velocity were measured on high‐gravity spiral concentrators using a depth gauge and a high‐speed camera, utilizing tracer particles. The velocity vectors indicate an increase in magnitude from the inner column to the outer edge. High‐gravity spirals show lower flow depths and free surface velocities but steeper depths in the outer zone than low‐gravity spirals.