Abstract: The theoretical and analytical model of separation speed of spiral groove face seal is introduced. A mathematical model of non-contacting double narrow spiral grooved seals is presented. The separation speed of double narrow groove face seal with outer spiral grooves and inner herringbone grooves is obtained. The influences of rotation speed and film thickness on the basic static cha- racteristics (opening force, leakage, friction torque and power loss) of non-contacting double narrow spiral grooved seals are discussed. Comparisons are presented between the measures and predications of an important parameter (separation speed) for a 100 mm diameter, narrow spiral groove (3 μm) face seal using water (27 ℃) as a test fluid. The results show that the non-contacting seal is formed at about 9 kr/min, and its leakage is about 1.2 mL/s. The relative errors between the measured and the predicted separation speed are less than 10%, and the parameter (separation speed) of the face seal is validated. When the rotation speed is higher than separation speed, the face seal is in non-contacting state, which has the low leakage and the long life. These findings provide the theoretical and experimental references for the design of reused face seal applied in the liquid rocket engine turbopumps.

Key words: Separation speed, Spiral groove face seals, Theoretical and experimental approach