Numerical and Experimental Study on Micro Cross Flow Turbine Including the Prediction of Sediment Erosion

Abstract

A hydro plant from 5kW up to 100kW is usually responsible to provide power for a small community or rural industry in remote areas away from the grid. It gives the best solution to the power need of rural and small communities which serves as decentralized power source to meet the local population requirement. Energy requirement for lighting cooking heating drying agro processing and other small scale industries activates can be met through these Micro hydro power (MHPs) in the most reliable way in the rural areas of the country like Nepal. Cross flow turbines are widely used in such MHPs due to their simple design, easier maintenance, low initial investment and modest efficiency. Also because of their suitability under low heads, efficient operation under a wide range of flow variations and ease of fabrication.

Numerical simulation and Experimental analysis was carried out to achieve the objective of the study. Previous studies and experiment conducted in the lab were used as the reference for the further studies. Computational fluid dynamics (CFD) simulations and experiments have been conducted at various rotational speed, guide vane angle and different flow rates and the result has been compared. The previous study mostly focused on the change in the shape of the nozzle components and the casing.

Based on such design the setup has been constructed. Performance study of the setup was conducted to validate the CFD results obtained. The change in the shape of the blade has been considered in this work and the performance with the change in nozzle has been studied. CFD simulation has been conducted for the change in the shape of the blade based on the inlet angle and the diameter ratio of the turbine. The change gives positive change in the efficiency and the performance of the turbine

The structural strength of the turbine has been analyzed based on the pressure points obtained from the CFD simulations. The forces exerted by the water on the surface of the blades has been mapped on the using the Ansys Workbench Structural analysis and the stress and the deformation on the turbine blade has been studied.

Sediment erosion is one of the key challenges in hydraulic turbines especially in the Himalayan from a design and maintenance perspective in Himalayas. The effect and has been studied of sediment erosion and its effects on the turbine has been done for the various size, shape and mass flow rate of the sediment particles.