Experimental study of the effect of blade angle on pico tubular bulb turbine performance in horizontal flow

At present, most of the small hydropower research literature focuses on the head between 2 and 30 meters, in contrast to the ultra-low head (ULH) between 0 and 3 meters undeveloped. ULH hydropower, especially for horizontal flow is attractive to develop because it is renewable, sustainable, simple, low cost, and environment-friendly. One type of ULH hydropower application in horizontal flow is the tubular channel, while the ultra-low of turbine used is a propeller. Efforts to increase the velocity of water flow and direct the current to the turbine in the tubular channel applying the bulb body. The blade angle is related to the gap between the blades in the turbine and will affect the discharge, so the performance of the turbine is also affected. This study aimed to determine the effect of blade angle on the propeller turbine characteristics on horizontal flow. The number of blades in this study was 5, with the bulb ratio to the pipe used 0.6. Blade angle variations of 15°, 20°, 25° and 30° with each tested at 7, 9, 11, and 13 L/s in horizontal tubular flow. The relationship between blade angle variations with rotation speed, dynamic head, shaft power, and efficiency in this study are displayed graphically. The results of this study indicate that a slope of 20° with a flow rate of 13 L/s produces optimal power compared to other angles.