Specific Internal Flow in Balancing Hole

Abstract

In order to research the discharge coefficient of a balancing hole C_d for a wide range of axial flow velocity v in the hole and rotational speed u, we carried out CFD simulations. Some of the results and the reported experimental data agree within the difference of about 5.3% on the pressure difference of the hole. Flow in a balancing hole is influenced by not only v but also u. Therefore the parameter v/u is considered as an important parameter of C_d. Furthermore, for very low range of v/u, we found a rare flow situation with S-shaped streamlines. Due to the strong pumping effect by rotating disk, C_d is greatly different in this region.