Large-Scale Particle Image Velocimetry of Natural and Mixed Convection

Abstract

Application of Particle Image Velocimetry to measurement of flows on large scales is a challenging necessity especially for investigation of convective air flows. By combination of helium filled soap bubbles as tracer particles with high power quality switched solid state lasers as light sources stereoscopic Particle Image Velocimetry on scales as large as 12.6 m² becomes possible. An indispensable requirement for such measurements is a bubble generator with high generation efficiency. A three channel bubble generator operating orifice nozzles was built in order to produce several thousand bubbles per second. The technique was applied to mixed convection in a full scale double aisle aircraft cabin mock-up for validation of computational fluid dynamic techniques and to natural convection in a large scale Rayleigh-Bénard facility for detection of characteristic convection patterns.