A Study on Static and Dynamic Characteristics of Spiral-Grooved Seals.

Spiral-grooved seals are often used for pumps because of lower leakage and removal of impurities through the groove path. In this study, the static and dynamic characteristics of the spiral-grooved stator/smooth rotor (SGS/SR) and the smooth stator/spiral-grooved rotor (SS/SGR) seals are investigated experimentally and theoretically. In the experimental study, the fluid forces and the leakages for five types of SGS/SR seals and a SS/SGR seal are measured under various conditions. In the theoretical study, a flow in the seal is divided into two clearance flows and a spiral groove flow. The governing equations for the clearance flows are derived using continuity and momentum equations. These equations are solved numerically by using the perturbation method. In the experiment, static and dynamic characteristics of the seals with large helix angles were measured and compared with numerical results. Then, the calculated forces, rotordynamic coefficients and leakages are in good agreement with the experimental results.