Multi-Directional Schlieren 3D-CT(Computer Tomography) Measurement of Instantaneous Temperature Distributions of Turbulent Flames

(Improvement in accuracy with Standard Refractive Index Gas Jets)

Abstract

Non-scanning 3D-CT(Computer Tomography) technique using a multi-directional quantitative schlieren system with flash light sources has been proposed to obtain instantaneous 3D density distributions of flames, supersonic jets and etc. This "Schlieren 3D-CT" is based on (i) simultaneous acquisition of flash-light schlieren images taken from numerous directions, and (ii) 3D-CT reconstruction of the images by an appropriate CT algorithm. In this paper, accuracy of this technique is evaluated and verified by checking with a standard refractive index distribution of a helium jet. Next, the verified 3D distribution of refractive index of premixed flames are successfully converted to appropriate temperature distribution.