Simultaneous Measurement of Distributions of Temperature, Soot, CO₂, and H₂O Concentrations for an Axisymmetric Ethylene Laminar Flame in O₂/CO₂ Atmosphere

Accurate measurements of temperature, soot volume fraction, and multiple gas-phase component concentrations are essential for enhancing combustion mechanisms. However, no method exists to measure these parameters simultaneously. Therefore, this study proposes a method for the simultaneous measurement of temperature, soot, and multiple gas-phase component distributions in axisymmetric ethylene laminar diffusion flames by combining emission-based tomography with large lateral shearing interferometry. Firstly, a hyperspectral camera is used to obtain temperature and soot volume fraction distributions through a radiative transfer model and a multi-wavelength temperature measurement algorithm. Simultaneously, a CCD camera records interference fringes, and the spatial phase distribution is extracted through image processing techniques and Abel inverse transformation. Using the acquired temperature distribution, correction coefficients that represent the distributions of gas-phase component concentrations are computed. Subsequently, preliminary distributions of gas-phase concentrations in the absence of combustion are derived based on the determined temperature and soot volume fraction distributions, considering flow, heat transfer, temperature, and C2H4 consumption during soot formation. For each spatial point, a set of equations representing gas-phase component concentrations is established, allowing the distribution of CO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O concentrations to be determined by solving these equations in a stepwise manner. An axisymmetric ethylene laminar flame in an oxygen-enriched CO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> atmosphere is experimentally analyzed, with the distributions of soot volume fraction, CO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>, and H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O concentrations verified independently.The analyzed flame, attains a maximum temperature of 2231 K, with a peak soot volume fraction of 13 ppm, and peak concentrations of CO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O at 0.71 and 0.28, respectively.