Micro-combustor performance enhancement using a novel combined baffle-bluff configuration

• Published in: Chemical engineering science 2018, Vol.175, p.243-256
• Main Authors: Ansari, Mehran, Amani, Ehsan
• Format: Article
• Language: English
• Subjects: Baffle-bluff; Efficiency; Emission; Micro-combustion; Micro-thermophotovoltaic (MTPV); Uniformity
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2017.10.001

•A novel combined baffle-bluff micro-combustor is proposed for MTPV applications.•At the optimal baffle thickness, the average temperature improves by 6% and uniformity by 87%.•The combustion efficiency is most sensitive to the baffle length.•The wall conductivity predominantly affects the entropy generation rate. This research is aimed at investigating a novel planar micro-combustor with combined baffle and bluff configuration for Micro-Thermo-Photo-Voltaic (MTPV) applications, numerically. It is shown that the novel combustor outperforms the similar configurations with only baffle or bluff, in terms of the flame stability, efficiencies, and emission. In addition, it is observed that the baffle thickness plays the key role in determining the flame location and, as the result, is the most important design variable controlling the temperature distribution and uniformity since the balance of heat transfer rates across the walls in different regions is significantly affected by this thickness. Moreover, small values of the bluff diameter and bluff-to-baffle distance result in performance improvements while the lower limit of these variables is set by the appearance of flame instability. In addition, for the optimal baffle thickness, the concurrent increase of 6.3% in the average wall temperature and 87.5% in the temperature uniformity are achieved. Finally, the sensitivity analyses reveal that the most effective parameter changing the combustion efficiency and entropy generation are the baffle length and wall conductivity, respectively.