Performance Analysis and Simulation of Savonius Wind Turbine for Small-Scale Water Pumping System

Abstract

Water is the most important source of life, and it is presently accessed through pumps. Centrifugal and positive displacement pumps are two types of pumps, with electrical, diesel, and renewable energy sources (Solar and Wind energies) as inputs. To solve environmental issues, wind energy has emerged as a new energy option. Wind energy is converted to the required energy using turbines. Based on the rotation axis, they are divided into two categories: horizontal and vertical. The Savonius wind rotor is a vertical axis wind turbine (VAWT) with a simple structure and a low operating speed, making it ideal for places with low average wind speeds. However, its application areas are limited due to its low performance. According to studies, the shape and number of blades, rotor stage, shaft influence, overlap ratio, endplate, blade angle of twist, aspect ratio, and fin addition all have a significant impact on S-VAWT performance. The purpose of this study is to use CFD methods to improve the performance of the S-VAWT for the water pumping system in the Dodota area by modifying aspect ratios and adding fins to the blade, and to compare the results to previous literature. The power delivered by the rotor is around 12.8 W while the power available in the wind is 40 W. From the wind power, the size of the rotor is calculated to pump the water needed. The rotor contains four turbine blades with a rotor diameter of 3 m, an endplate diameter of 3.3 m, a rotor height of 2.4 m, and an aspect ratio of 0.8. SOLIDWORK 2018 was used to create the 3D model of the Savonius rotor, and ANSYS 19.2 was utilized to simulate it. The study was carried out throughout the dry season using the National Metrology Agency of Ethiopia wind speed data, with an average value of 2.15 m/s. The fin is used to direct the wind flow by filling the space in the blades. The results showed that when two fins are added, the pressure distributions and velocity distributions are higher than when only one fin is used or when without a fin is used. With the addition of two blades, the power coefficient, 𝐶𝑝 in this study increases by an average of 0.256. This result is higher compared to previously done by Ridwan et al, 2019 which was 0.241.