Optimization of the Operational Conditions for Cross Flow Turbine Developed for Power Generation

Abstract

In a bid to optimize the performance of a Cross Flow Turbine designed and fabricated by Oyebode (2014), the performance evaluation of the turbine at various conditions was carried out using a portion of the overflow from the University of Ilorin (UNILORIN) dam. The Dam has a net head of 4 m, flow rate of 0.017m³ and hence theoretical hydropower energy of 668W. The turbine was tested and the optimized value of operating conditions namely; angle of inclination of the water jet (15^o above tangent, tangential and 15^o below tangent), height of water jet to impact point (200mm, 250mm and 300mm) and length of the water jet to impact point (50mm, 100mm and 150mm) were pre-set at their various levels while testing the Turbine. The measured outputs were Turbine Speed, Turbine Torque, Alternator Speed as well as the output voltage. The optimum values of the process output or measured parameters were determined statistically using a 3³X2 factorial experiment in three replicates. An optimum turbine speed of 330.09 rpm was achieved by pre-setting 250mm height to impact point, 100mm length to impact point and the water jet 15º below tangent. Same combination also yielded an optimum turbine torque of 39.07kNm. During loading (i.e. when the alternator becomes connected to the turbine), an optimum Turbine Speed of 197.66rpm was achieved by pre-setting 250mm height to impact point, 100mm length to impact point and the water jet 15º below tangent. Same combination also yielded an optimum Turbine Torque of 25.02kNm, optimum Alternator speed of 879.24rpm and an optimum output voltage of 4.05V. The results therefore show that the turbine must be set at these operational conditions for it to perform optimally.

Key words: Micro hydropower, Cross Flow turbine, Power generation, Dam overflow