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

Abstract

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 ΔBsum 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 ΔBsum, 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.