Development of an inline bidirectional micro crossflow turbine for hydropower harvesting from water supply pipelines

Reliable and continuous power supply to the data monitoring and transmitting devices of the water intelligent network (WIN) system of urban water supply pipelines is still a challenge due to the restricted underground space and complex water environment. In this study, a novel inline bidirectional vertical crossflow turbine (IBVCT) integrated with bell-mouth guide blocks was developed to generate hydropower by converting the excess po- tential energy of the water flow onsite for power supply to the WIN system in Hong Kong. Specifically, the configurations and geometries of the proposed IBVCT were designed for large-size pipelines, and four schemes of water blocks in IBVCT were investigated based on the computational fluid dynamics method to determine the optimal configuration. A hydraulic test rig in the laboratory and a field test system integrated with an electricity storage module were developed. The IBVCT, after numerical optimizations, was fabricated and tested to validate its overall performance of power generation, water head loss, and long-term operating stability. The results showed that the designed centrosymmetric bell-mouth guide blocks significantly contribute to the efficient conversion of water flow energy into mechanical energy by the turbine. The IBVCT prototype had the best ef- ficiency of 2.6 % at the water flow velocity of 1.3 m/s, which was capable of providing stable and sufficient electric power with a daily electricity generation capacity of 470 Wh. Additionally, the water head loss was effectively restricted within 6.1 m at the high water flow velocity of 3 m/s. These technology metrics of the IBVCT exhibited superior overall performance and met the power requirements of the WIN system used in the main urban water pipelines.