A potential solution to recover energy from wastewater environment by using the single-channel pump as turbine

Hydroelectric turbines can become clogged by trash in the water source, which can damage the blades and reduce the performance. Thus, a turbine that can operate efficiently in trash-filled water environments is needed. In this study, a single-channel pump for operating in turbine mode is proposed as a potential solution to recover energy from a water source containing trash. To evaluate the operational capability in turbine mode, the hydraulic characteristics, radial force, and vibration were analyzed in detail by the computational fluid dynamics. Experiments were performed to confirm that SPAT could operate in trash-filled water environments and to validate the reliability of the numerical results. SPAT had a lower hydraulic efficiency in turbine mode than in pump mode, which can be attributed to the appearance of a vortex rope rotating around not only itself but also the rotating axis of the runner. The vortex rope caused large energy losses but also facilitated the movement of trash through the pump. The net radial force was lower in turbine mode than in pump mode, but the greater eccentricity of the radial force in turbine mode resulted in stronger vibrations. • Single-channel pump can operate in turbine mode with an efficiency of up to 79.585%. • Losses in turbine mode were mainly attributed to the unsteady vortex rope. • Virtual rotating axis deviated 1.53 times further in turbine mode than in pump mode. • Swept area, average net radial force in turbine mode were smaller than in pump mode.