EXPERIMENTAL STUDY OF SAVONIUS MODIFIED BACH WITH TWISTED PROFILE AND VALVE ADDITION

• Main Author: Razaq, Fakhri
• Format: Theses
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/81678
• Institution: Institut Teknologi Bandung

The Savonius wind turbine is preferable for small or micro scale applications, because it has better self-starting ability at low speed and omnidirectionality ability. However, one drawback of Savonius wind turbine is its low coefficient of performance (Cp). Modifying the shape of the turbine blade and adding valves to the turbine blade can improve the performance coefficient value. This research aims to enchance the performance coefficient by altering the blade shape to twisted modified Bach profile with twist angles (15O, 30O, 45O, 60O, 90O, dan 120O) and adding valves to twisted modified Bach profile at twist angles of 15O and 120O in three different posisitions. The research results show that modifying the twist angles to 60O, 90O, and 120O on turbine blades leads to significant increase in Cp value. The highest Cp improvement is observed at twist angle of 120O, with an increasing Cp value 6,1% at a wind speed of 6,2 m/s and 9,7% at a wind speed of 8,45 m/s. Adding valves to the twisted modified Bach of 15O does not significant affect the turbine’s Cp value at a wind speed of 6,2 m/s. However, adding valves at a wind speed of 8,45 m/s gives positive results with the largest Cp value of 0,257 (2,4%) achieved by placing the valve at blade tip. On the other hand, adding valves to the twisted modified Bach of 120O negatively affects the turbine’s performance coefficient (Cp) at both wind speeds (6,2 m/s and 8,45 m/s). This study demonstrates that modifying the twisted modified Bach profile can indeed influence the turbine’s performance coefficient (Cp). While adding valves to the twist angle of 15O has minimal impact and gives negative effect to the twist angle of 120O. This discrepancy may be due to the free wind flow passing through the concave part of the turbin blade, resulting in wasted airflow through the valve holes. Additionally, the shape of the twist angle itself palys a role, as the minimum Cts value generated is positive, indicating suboptimal valve function.