Accession Number : ADA134691

Title :   Laser Diagnostic Development and Measurement and Modeling of Turbulent Flowfields of Jets and Wakes. Part 1. Two-Dimensional Laser Doppler Anemometer Studies of Isothermal Flowfield in a Ducted Centerbody Combustor.

Descriptive Note : Final rept. 1 Apr 78-30 Sep 82,


Personal Author(s) : Lightman,A J ; Magill,P D ; Andrews,R J

PDF Url : ADA134691

Report Date : Jun 1983

Pagination or Media Count : 139

Abstract : A two-dimensional laser Doppler anemometer was designed to take measurements in a ducted coaxial flow system having a centerbody separating the jets. The measurements, made in isothermal flow, can be categorized as: central jet only (C02); annular jet only (air); and, combined central and annular jet flow. Radial profiles of the axial and radial/azimuthal velocity were obtained. The central jet only condition approximates a free jet since the central jet diameter is much smaller than the centerbody or duct diameter (1:29.3: 53.2). Measurements of the jet development (diameter, turbulence intensity, etc.) were compared with previous free jet studies. In a study of the isotropy of the turbulent fluctuations it was determined that fully developed turbulent flow begins further downstream than anticipated. Velocity profiles were combined with gas sampling measurements to ascertain jet entrainment. Results show a linear growth of the entrained mass starting at the entrance plane. Downstream (20 diameters) the rate of growth increases to match past studies in that region. The annular jet flow creates a recirculation vortex in the wake of the centerbody. The flowfield was mapped and the streamlines describing the flow were obtained throughout the recirculating flow and further downstream.

Descriptors :   *Laser anemometers, *Jet flow, *Turbulent flow, *Gas flow, Recirculation, Vortices, Entrainment, Doppler systems, Two dimensional, Profiles, Wake, Flow fields, Measurement, Isotherms, Mathematical prediction, Air, Coaxial configurations, Carbon dioxide, Experimental data, Data acquisition, Polarization, Rings, Ducted bodies, Combustors, Diagnosis(General), Mass flow, Velocity

Subject Categories : Lasers and Masers
      Test Facilities, Equipment and Methods
      Fluid Mechanics
      Combustion and Ignition

Distribution Statement : APPROVED FOR PUBLIC RELEASE