Abstract:
Pakistan is a developing country that is currently facing severe power demand-supply gap due to high population, rapid urbanization and traditional means of power generation. The heavy dependence of power sector on imported fossil fuels enforces an unembellished burden on economy of Pakistan and poses threatening environmental concerns. This study aims to evaluate the technical feasibility of a Gorlov (Helical Type) Vertical Axis hydrokinetic turbine to be installed in low-pressure, low-head open flow channels, targeting the rivers and canals worldwide. The analytical foundation was based on Q-Blade simulations employing Double Multiple Stream Tubes (DMST) theory to propose a turbine design with optimum power generation and self-starting capabilities under design conditions.
The various parameters impacting turbine design include radius of the turbine, chord length, aspect ratio, solidity and blade wrap. Multiple designs were considered and a non-dimensionalized trend was obtained for turbine efficiency and self-starting capability at various aspect ratios with decreasing efficiencies for increasing solidity values thereby constituting a trade-off between aforementioned operating characteristics. A SolidWorks CAD package was used to develop a model for virtual analysis and construction. The results produced by analytical modeling were then verified by conducting a rigorous three-dimensional Computational Fluid Dynamics analysis under transient conditions. Standard initialization was used with calculated initial conditions to ensure maximum convergence rate.
The results show that the proposed 4-blade turbine with 0.38m height, 0.25m diameter, 100% blade wrap, NACA-0018 airfoil, 0.25 Coefficient of Performance, 0.29 solidity will produce up to 63 W power and 4.3 Nm torque at maximum flow speed of 2.7ms-1. The manufacturing will include 3D printing the blades to create the mold for casting. The wet operating conditions for various parts of the assembly were factored in the choice of materials.
