Investigation of friction power consumption and performance of a water turbine seal based on the imbalanced rotation of nano-magnetic fluids

The calculation of friction power consumption and the performance of nano-magnetic fluids in sealed water turbines have proved to be hurdles in studies on nano-magnetic fluidic device designs and applications. In this article, we investigate the imbalanced rotation Ω ≠ 1/2 ( rot υ ) of a nano-magnetic fluid suspended in a paramagnetic carrier liquid. Through Langevin and Navier–Stokes equations, the formula for the theoretical friction power consumption can be calculated for the magnetic particles in the nano-magnetic fluid. The calculated value shows a well agreement with the test result. Further simulation indicates that the magnetic field gradient Δ B sum between the tooth space (wave trough) and the pole tooth (wave crest) has the most influence on the imbalanced rotation in a sealed nano-magnetic fluid device in a water turbine. Specifically, the larger the Δ B sum , the more obviously imbalanced the nano-magnetic fluid rotation will be at that location; and the imbalanced torque will be larger, so the seal differential pressure will be as well. As a result, the sealing capacity will be better and the frictional power consumption will be larger; and the reverse is also true. This study result can serve as a reference for designs for sealed nano-magnetic fluidic devices for water turbines, which is significant, especially given the heat from friction power consumption in the water turbine and its cooling equipment.