A Comparative Study of Biogas/Air Flames Characteristics for Different Bluff-Body Burner Configurations

Abstract

This study investigates the biogas/air bluff-body stabilized flames, focusing on the effects of different burner configurations on combustion characteristics. The configurations include bluff-body angles of 30°, 45°, 60°, and 90°, with positions adjusted upstream and downstream of the burner exit. The experimental setup involves a biogas mixture with varying CO_2 percentages, maintaining a constant thermal input. Results demonstrate that increasing CO_2 up to 10% enhances flame temperature and emissions, while higher concentrations reduce flame reactivity. The flat bluff-body (90°) produces the highest exhaust temperature due to its longer flame length, while the 60° angle results in lower temperatures with a wider, shorter flame. CO emissions decrease as the bluff-body moves upstream or downstream, correlating with higher temperatures, while NO emissions increase. Additionally, NO concentrations decrease with rising CO_2 percentages due to the dilution effect. These findings provide valuable insights for optimizing biogas bluff-body burners, contributing to more sustainable energy solutions.