Matched Index Laser Anemometry Systems for Flow Studies in Complex Geometries,
CASE WESTERN RESERVE UNIV CLEVELAND OH CHEMICAL ENGINEERING DIV
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Optical access to the flow is necessary if laser anemometry is to be used to map a given flow field. Often this access is difficultimpossible to obtain because of the shape of the object about which or within which the flow exists. Examples are flows in porous media, fluidized beds, heat exchangers or near sinusoidal surfaces. Making the object of transparent material such as of glass or plexiglas is not sufficient to provide a reliable, usable optical environment for laser measurements. It is often necessary to use a fluid whose index or refraction matches that of the object. At the Case Center for Complex Flow Measurements, at Case Western Reserve Univ., we have constructed a matched index of refraction flow system. This paper describes this system and present examples of measurements made with this system. In particular, this paper discusses 1 When index matching is needed 2 How close the match has to be 3 Practical details of operating an index matched facility and 4 Flow measurements made using an index matched facility to study boundary layer transition due to roughness, the flows within rod bundles and the flow regimes within porous media.
- Fluid Mechanics
- Lasers and Masers