Efficient Laser Anemometer for Intra-Rotor Flow Mapping in Turbomachinery

Abstract

Innovative features of the anemometer include:(1) a rapid and efficient data acquisition process, (2) a detailed real-time graphic display of the data being accumulated, and (3) input laser beam positioning that maximizes the size of the infra -riLUL region being mapped. Results are presented that demonstrate the anemometer's capability in flow mapping within a transonic axial-flow compressor rotor. Typically, a velocity profile, derived from 30 OOU measurements along 1000 sequential circumferential positions covering 20 blade passages, can be obtained in 30 seconds. The use of fluorescent seed particles allows flow measurements near the rotor hub and the casing window.INTRODUCTIO"'

Unsteady flows in a single-stage transonic axial-flow fan stator row

“…The LFA system minicomputer was used to control the data acquisition procedures via an automated data acquisition program [75], which Is set up to sequentially acquire data at each of the survey points specified In the survey file. At each of these survey points, the LFA system was free to acquire velocity measurements whenever a seed particle crossed the LFA probe volume, which resulted In the random acquisition of many velocity measurements during every rotor revolution.…”

Measurements of the Unsteady Flow Field Within the Stator Row of a Transonic Axial-Flow Fan: I — Measurement and Analysis Technique

“…The laser anemometer system used in the present experimental investigation is a single channel, dual beam, fringe anemometer with on-axis back-scatter collection optics. The system has been previously described in detail (7). The laser fringe anemometer (LFA) is used to obtain information about the ensemblemean velocity and ensemble-variance of the velocity fluctuations in any desired direction within a plane perpendicular to the laser beam optical path.…”

Investigation of Flow Phenomena in a Transonic Fan Rotor Using Laser Anemometry

“…_!!#h_! !laser anemometer(LA) system used in the present Ingestlgatlonis a slng_e channel fringe anemometerwhich has been previouslydescribed in detail (4_ 13,14). Optical access to the flow field is providedby a 3 mm thick gl_ss wi'ndow which conformsto the outer flowpath contour in both the circumferential and streamwisedirections.…”