Numerical modelling of axial outlet hydrocyclone

Abstract

Nepal possesses huge networks of perennial rivers and together with the steep topography, the rivers of Nepal prospects enormous hydroelectric potential. However, due to significant amount of sediments in the rivers, the hydropower plants suffers considerable losses due to damages in turbines and other hydromechanical equipment’s. Since the gravity-based settling basins, designed for handling suspended sediments has been found inefficient, this study focuses on use of centrifugal separation method for better handling of suspended sediments. This paper presents the simulation of axial outlet hydrocyclone using ANSYS Fluent software. The simulation is first validated with the physical model in terms of both water distribution and sediment throughput. Subsequently, the hydraulic performance of the device is analysed by studying various velocity profiles and headloss in the device. Finaly, the device performance is assessed at various angle of inclination of its axis at 90o, 60o, 53o, 45o and 30o to horizontal with an intent to reduce the overall height of device considering difficulties in excavation in rugged topography of Nepal. It was observed that the sediment separation efficiency decreased, particularly for very fine sediments with reduced headloss by 0.071 m as the axis of device was changed from 90o to 30o to horizontal.