Performance Evaluation of H₂/Air Premixed Combustion in a Suddenly Expanded Microcombustor with Wall Fin

Abstract

Herein, a 2D, axisymmetric microcombustor with a backward‐facing step and triangular wall fin is considered for enhancement of combustor performance. The outer wall temperature, combustor efficiency, and pressure characteristics of the microcombustor are numerically investigated with a detailed chemical kinetic mechanism and conjugate heat transfer. The proposed microcombustors with variable blockage ratios, wall fin shapes, and locations are analyzed with respect to flow and combustion interaction, along with heat flux exchange between the flame and combustor wall. Combustion performance is also evaluated by means of the amount of heat transferred through the combustor wall, conversion ratio of input chemical energy to exploitable heat, and OH mass fraction distributions. Standard k–ε turbulence along with 9 species and the 19‐step combustion reaction scheme is implemented using the eddy dissipation concept (EDC) model in the numerical study. The results indicate that the wall fin blockage ratio alters the reaction zone and improves combustor performance significantly at lower inlet velocities (4–20 m s−1). The fin location and shape are observed to influence the temperature distribution. However, the higher blockage ratio adversely impacts the combustion characteristics at the higher inlet velocity, that is, 48 m s−1.

Effect of Turbulence and Diffusional–Thermal Instability on Hydrogen‐Rich Syngas Turbulent Premixed Flame

“…Therefore, the research of turbulent premixed combustion is very important for the clean and efficient utilization of fossil fuels and for the design and development of industrial burners. [10][11][12][13][14] The research on the propagation properties of turbulent premixed flame is also the focus many scholars' works. [15,16] The common experimental devices of turbulent premixed flame are jet burners, [17][18][19] constant volume burners, [20][21][22] swirl burners, [23,24] and hedge flame burners.…”

“…Therefore, the research of turbulent premixed combustion is very important for the clean and efficient utilization of fossil fuels and for the design and development of industrial burners. [ 10–14 ]…”

Numerical investigation of H2/Air fueled micro combustion characteristics with trapezoidal ribs for micro thermophotovoltaic applications: Effect of rib height

“…They also observed that employed two ribs delivered better thermal performance. Qamareen et al 32 studied a 2D micro combustor with a backward-facing step and triangular wall fin, observing improved performance at lower inlet velocities (4-20 m/s) due to the fin blockage ratio. Fin location and shape affected temperature distribution and combustion performance.…”

Numerical investigation of the effect of the slit profile on the combustion characteristics of a micro-combustor with a centrally slotted bluff body

“…The invasive techniques significantly affect the flow field inside the combustor while the non-invasive techniques have no effect on the fluid flow inside the combustor. The invasive techniques include design modifications of the combustor cross section area, 5 insertion of fins, 6,7 flame plate holder, 8 porous medium, stepped combustor, bluff body, wall cavities and ribs etc. 9 Inspired by the presence of bluff bodies in macro-scale industrial combustors, 10 bluff body induced micro-combustors were proposed.…”