Flow Measurements in Enlarged-Bore Seal Chambers

Abstract

Laser doppler velocimetry (LDV) and high speed video photography were used to measure flow velocity and visualize solid particle motion within enlarged bore seal chambers. The measurements were obtained at two shaft rotational speeds for an impeller with and without balance holes. The respective flow Taylor numbers for the two shaft speeds are 3.37 × 109 and 1.6 × 109; the Reynolds numbers are 3.52 × 105 and 2.43 × 105. A Taylor vortex extending along the seal chamber length was measured at these Taylor numbers. The presence of balance holes in the impeller causes higher velocities and turbulence intensities compared with the same operating conditions when balance holes are plugged. For the impeller with balance holes, the effect of the Taylor vortex in mixing the chamber flow is measurable. The flow at a lower Taylor number resembles that at the higher Taylor number, but with lower magnitudes of circumferential velocity and turbulence intensity components. Solid particles with a mean diameter of approximately 40 μm or less follow the Taylor vortex flow. Larger particles are trapped near the gland plate and cause erosion. Protrusions in the chamber drastically reduce the solid particle concentration. Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998