Experimental and on-site investigation of the in-line vertical axis water turbines for water pipelines

Abstract

Health monitoring devices are critical for the safe and reliable operation of water supply systems, but their chemical batteries are easily depleted. Thus, this paper developed a micro-vertical axis water turbine that converts part of the water head into electrical energy and supplies power for the monitoring device. The performance of four groups of micro-turbines was investigated in detail through experimental testing. Different from our previous study, the entire performance curves of micro-turbines at different rotation speeds and flow velocities were obtained in order to consider the wide range of flow velocities inside the real water pipeline. The feasibility of the designed turbines in the power supply system was verified by on-site testing. The experimental results show that different types and opening sizes of blocks have a distinct influence on the output power of micro-turbines. Each type of block has the corresponding optimal opening size to gain the highest performance. Within a certain range, the maximum output power varies linearly with the increase in flow velocity. In a specific flow velocity, the optimal rotational speed of the micro-turbine generated the maximum output power can be predicted by the power curve. In addition, through the experimental data, it is found that among all the measured turbines, the 12-blade hollow shaft turbine with a 90% eye-shaped block is the best one, with an output power of 88.2 W and an efficiency of 15.76%. Finally, the results of an on-site test are consistent with that of the experiment properly, which verifies the reliability of the measured data in the laboratory.