Spanwise recirculation zone structure of a bluff body stabilized flame

Combustion Characteristics of Methane-Air Mixtures in Millimeter-Scale Systems With a Cavity Structure: An Experimental and Numerical Study

“…A sufficiently low velocity must be retained in the region where the flame is desired in order to sustain the flame. As is known, a region of low velocity in which a flame can be sustained can be achieved by causing recirculation of a portion of the fuel-air mixture already burned thereby providing a source of ignition to the fuel-air mixture entering the combustion zone (El-Asrag and Menon, 2007;Fugger et al, 2020). However, the fuel-air mixture flow pattern, including any recirculation, is critical to achieving flame stability.…”

“…The typical method includes the use of recirculation regions to provide a continuous ignition source by mixing the hot combustion products with the cold incoming fuel and air mixture. Structural devices have been commonly employed to establish a recirculation region for improving the stability of the flame during ignition and operation, such as swirlers (Yilmaz et al, 2020), bluff bodies (Jeong et al, 2017;Fugger et al, 2020), cavities (Yilmaz et al, 2017), and rearward facing steps (Yilmaz et al, 2017). The challenge, however, is presented with respect to the structure of a flame stabilizer that ensures high combustion performance, including improved flame stability and acceptable emissions (Khateeb et al, 2020;Khateeb et al, 2021) while reducing capital and operating costs.…”