TURBULENCE MEASUREMENTS OF HIGH-SHEAR FLOW-FIELDS IN A TURBOMACHINE SEAL CONFIGURATION

The mean velocity and Reynolds stress tensor throughout a whirling ann ular seal are presented. The data were collected with a three-dimensio nal laser Doppler velocimeter using phase averaging. Two axial flow co nditions (Re = 12,000 and 24,000) were studied at one shaft speed (Ta = 6,600). The eccentricity and whirl ratios were 50 percent and 100 pe rcent, respectively. There is a region of high axial momentum at the i nlet on the pressure side of the clearance that migrates around the se al to the suction side al the exit. The normalized axial momentum in t his region is higher in the low Reynolds number case due to an axial r ecirculation zone that occurs on the suction side of the rotor at the inlet. The recirculation zone does not occur in the high Reynolds numb er case. At both Reynolds numbers there is a recirculation zone on the rotor surface in the pressure side of the inlet. This recirculation z one extends from 20 to 200 deg past the rotor zenith in the tangential direction, and is one third of a clearance wide radially. The high Re ynolds number circulation zone is 1.5 mean clearances long, while the low Reynolds number zone extends two mean clearances downstream. When compared to previous studies, it is apparent that the tangential momen tum is no greater for a seal with whirl than for one without if other parameters are constant. Areas of high tangential momentum occur in th e clearance where the axial momentum is low. Average exit plane tangen tial velocities in the low Reynolds number case are 1.5 times greater than those in the other flow case. These results are in general agreem ent with predictions made by other investigators.