Study of the effects of flow and temperature rise within the operation of twin-screw controlled pumps for seawater desalination

Based on the effects of rotational speed, clearance leakage, and rotor structure, this study analyzes the hydraulic performance and temperature rise of a specific twin-screw pump (TSP) through numerical simulations and experimental validation. The findings reveal that rotational speed significantly influences both the hydraulic performance and temperature rise of the TSP. As the rotational speed increases, the flow rate rises, while power demand decreases. Clearance leakage plays a crucial role in energy loss and temperature rise. At high rotational speeds, the increased leakage velocity results in a reduction in rotor surface temperature. Additionally, changes in rotor structure and flow patterns lead to uneven thermal distribution at high rotational speeds. The temperature at the rotor's outer edge and the tip clearance can reach up to 440 K, with localized thermal loads concentrated in certain areas. To balance the temperature rise while maintaining performance, achieving a rotational speed exceeding 20% of the rated speed is identified as an effective strategy. The comparison between computational fluid dynamics (CFD) and experimental results confirms the accuracy of the numerical approach, with a deviation of less than 5%. This study provides valuable insights for optimizing TSP design, particularly in areas related to rotational speed, clearance leakage, and thermal management.