Development of a three-dimensional Laser Doppler anemometry system: With measurements in annular and labyrinth seals.

摘要

A 3-D Laser Doppler anemometry system has been developed. This system was specifically developed to make measurements very close to solid surfaces (within.020 mm) in water. This system will allow measurement of mean velocities and the entire Reynolds stress tensor. A seven cavity labyrinth seal (cavities 1,3,5,7 were investigated) 3.20 cm in length and an annular seal, 3.73 cm in length, operating at a Reynolds number of 28,000 and a Taylor number of 7,000 were studied. The clearance in both cases was approximately 0.127 cm.; The investigation included measurements made with inlet preswirl (both positive and negative) and eccentricity (approximately 50%). Vorticity, production of turbulence kinetic energy, and the turbulent kinetic energy were calculated based on the measured mean velocity and Reynolds stress distributions. This information has lead to a better understanding of the flow field in these seals by providing data to numerical modelers. Throughout the measurements it was seen that areas of high shear and mixing produce the largest turbulence quantities. This will contribute to further research on how these seals work, how they might affect rotordynamic stability, and result in a more thorough understanding of turbulence in highly sheared flows.