Effect of composition distribution on holographic temperature measurement of a diffuse flame

The application of phase shift holographic interferometry to non-intrusive temperature measurement of a laminar, axisymmetric, propane diffuse flame is investigated. In our previous work the effect of composition changes on the holographic temperature measurement of reacting flows was experimentally studied for cases with axisymmetric, propane, laminar premixed lean flames (PLFs) and partially premixed flames (PPFs). To further examine this effect, in this work the effect of the diffuse flame (DF) is investigated. It has been shown that for the DF, the composition distribution is the most complicated and the composition effect is more severe than that of the PLF and the PPF. In order to obtain accurate and satisfactory holographic results, it is necessary to measure the species concentration at lower flame heights, and to use linear interpolation of the molar refractivity at higher test sections.