PHASE AVERAGED WALL SHEAR-STRESS, WALL-PRESSURE, AND NEAR-WALL VELOCITY-FIELD MEASUREMENTS IN A WHIRLING ANNULAR SEAL

The flow field inside a 50 percent eccentric whirling annular seal ope rating at a Reynolds number of 24,000 and a Taylor number of 6600 has been measured using a three-dimensional laser-Doppler anemometer syste m. Flush mount pressure and wall shear stress probes have been used to measure the stresses (normal and shear) along the length of the stato r. The rotor was mounted eccentrically on the shaft so that the rotor orbit was circular and rotated at the same speed as the shaft (a whirl ratio of 1.0). This paper presents mean pressure, mean wall shear str ess magnitude, and mean wall shear stress direction distributions alon g the length of the seal. Phase-averaged wall pressure and wall shear stress are presented along with phase-averaged mean velocity and turbu lence kinetic energy distributions located 0.16c from the stator wall, where c is the seal clearance. The relationships between the velocity , turbulence, wall pressure, and wall shear are very complex and do no t follow simple bulk flow predictions.