Hydropower is one of the most common forms of the renewable energy source of electricity. According to estimates, around 50 % of the small hydropower in India is shared by micro and mini hydro segments. Present research intends to develop a bulb turbine without guide vanes which can provide a sustainable solution for optimal utilization of micro- and mini-hydropower potentials, with a specific emphasis on low heads turbines. An average maximum flow rate of 1.6 m3/s and a net head of 13.2 m (site data) was selected as the primary input parameters required for the prototype turbine. A mean line design approach was carried out to calculate geometric and flow parameters. Efficiency and specific speed were determined through an iterative process.
Subsequently, a 9 kW lab-scale model turbine was designed using similarity laws and the geometric and flow parameters were evaluated for the same. CFD analysis was conducted to generate the performance map accounting for design and off-design flow conditions. A detailed static structural analysis was carried out to determine suitable material for runner blades and struts for support. Based on this numerical analysis, a turbine model was fabricated and tested in a closed-loop hydraulic turbine experimental test facility explicitly created for this purpose. Numerical predictions showed a reasonable matching with the designed values and a reasonable agreement with the experimental data at part-load conditions. Results have indicated that the turbine design shows an attractive feature of a reasonably flat efficiency curve and can produce a power output close to 9 kW. The efficiency can be improved further by improving the draft tube and runner efficiency.