Effect of Ultra-low Vegetable Oil Droplets on Microporous Media Burner Under Surface and Submerged Flames

This study presents experimental and numerical works on porous media burner. The influence of ultra-low vegetable oil droplets on burner performance was investigated. A unique dual-layer microporous media burner was fabricated to generate surface and submerged flames under lean conditions. Optimum equivalence ratio under lean conditions for surface and submerged flames was recorded at 0.7 and 0.5, respectively. The performance of the burner was examined by adding vegetable oil droplets of 20, 40, 60, or 80 μL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu \hbox {L}$$\end{document} externally on the surface of reaction layer. At 80 μL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu \hbox {L}$$\end{document}, the burner was at its best performance, while >80μL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$>80 ~\upmu \hbox {L}$$\end{document} leads to unstable flames. The maximum thermal efficiency of the burner under surface flame without droplets was found out to be 90%, which was enhanced to 94% by enabling 80 μL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu \hbox {L}$$\end{document} of vegetable oil. Similarly, with submerged flame maximum thermal efficiency progressively improved from 38 to 45%. The impact of vegetable oil at the microscopic level was determined by performing scanning electron microscopy and X-ray diffraction analysis. Digital thermal images were captured at critical ER to ensure a stable combustion. The emitted combustion gases were monitored continuously to detect the emissions (NOx and CO). These emissions were within controlled limits. Finally, three-dimensional numerical study was performed to effectively comprehend the experimental data for both temperature and emissions.