Pengaruh Besar Sudut Butterfly Guide terhadap Unjuk Kerja Kincir Air

Abstract

In this work, the effects of geometry transition of the upstream channel on the performance of an undershot water wheel were investigated. For that purpose, we carried out experiments using an undershot water wheel model with a diameter of  Ø=480 mm, the width of l=100 mm, the number of blades of 12, and the radius of blade curvature of R=170 mm, which was installed on a flow channel with the width of 250 mm. The upstream channel was modified by installing flow guides with different entry angles (α=30o, α=45o, and α=60o), and their effects were investigated by measuring the mechanical power of the water wheel and capturing the flow pattern at the upstream of the water wheel, under the flow rates of Q=10 l/s and Q=14 l/s. The experimental results show that the higher the flow rate, the stronger the effects of the flow guides on the performance of the water wheel. Under the considered experimental conditions, the highest performance was achieved for the flow guide with entry angles of α=30o at the flow rate of Q=14 l/s, for which the water wheel produces mechanical power of 22 Watt with an efficiency of 40,37%. It can be observed that the flow guide with the gradual transition (lower entry angle) introduces a more uniform flow pattern that results in a higher water wheel performance, while the flow guide with the sharp transition (higher entry angle) introduces the crossing flow pattern that reduces the performance of the water wheel.