Structure optimization of guide vane on combustion performance of premixed H 2 /air in micro cavity-combustor

Abstract

The application of the cavity-combustor in the micro-combustion is one proposal to stabilize the flame and improve the combustion performance. The structure of the guide vane is an important factor of enhancing the effectiveness of the cavity, which is a key part of the cavity-combustor. Based on previous studies on the micro cavity-combustor with guide vanes, numerical analysis was performed on the effects of the shape of the guide vane on the combustion characteristics of the premixed H2/air. The investigation and comparison were conducted for the micro cavity-combustor with slash-shape guide vanes (CCSG) and L-shape guide vanes (CCLG) under different inlet velocities (6–24 m/s) and equivalence ratios (0.6–1.5). The analysis results show that CCSG has better flame stability and combustion performance compared to CCLG. A multi-objective optimization method for the guide vane structure of the combustor was proposed and the optimum parameters were obtained by applying it to the CCSG. The length of the guide vane (L3) and the vertical distance between the guide vane and the wall (S) were used as parameters, and the problem of minimizing the combustion efficiency and total pressure loss in the combustor was set. The relationship between the structural parameters of the guide vanes and the combustion performance in the combustor was modeled using the BP (back propagation) neural network. The validation of optimization was verified through comparative analysis of the original structure (L3 = 0.5 mm, S = 0.15 mm) and the optimum structure (L3 = 0.5324 mm, S = 0.3834 mm).