Abstract
In order to balance the axial thrust of turbo machines, devices such as balancing disk, balancing hole and sealing system are used. However many of these devices become complicated and make problems such as the vibration by balancing disk. In order to control and balance the axial thrust, a very simple device of using shallow grooves mounted on a casing wall, known as the "J-Groove", is proposed and studied experimentally and theoretically. This study shows the effect of the J-Groove is estimated by putting a term in the equation of angular momentum on the gap flow, and it is possible to estimate the effect to the various parameters of grooves.
