Structure Optimization of Hydrogen‐Fueled Multiple Direct‐Injection Trapped Vortex Combustor Using Response Surface Method

Abstract

A hydrogen‐fueled multiple direct‐injection trapped vortex combustor is proposed to improve the unstable combustion and reduce NO emission. The effects of bluff‐body depth, bluff‐body height, and bluff‐body angle on the combustion flow characteristics are analyzed. NO emission is used as the main response value, the response surface method (RSM) is adopted to optimize the bluff‐body depth, bluff‐body height, and bluff‐body angle. The results show that the bluff‐body depth, bluff‐body height, and bluff‐body angle have significant effects on the NO emission, with the increase of the three parameters, NO emission first drops and then rises, but the effects on the pressure loss and outlet temperature distribution factor (OTDF) are very small. After optimization by RSM, the optimal bluff‐body parameters are the bluff‐body depth a = 56.5 mm, the bluff‐body height b = 128.9 mm, and the bluff‐body angle α = 77.6°. Under these circumstances, the maximum radial distances of the front concave vortex and the rear concave vortex reach 48 mm and 57 mm, respectively, which enhances the combustion stability. Furthermore, NO emission of 1.64 ppmv in the optimization structure is significantly optimized compared to NO emission of 4.32 ppmv in the original structure.