Study on synergistic heat transfer enhancement and adaptive control behavior of baffle under sudden change of inlet velocity in a micro combustor

Abstract

The rapid advancement of micromachining technology has led to the proliferation of micro-combustors in both civilian and military applications, and the actual operation process requires the ability to adapt to complex working conditions. The sudden change of the operating conditions poses a huge threat to the flame stability in micro-combustion, but the flame regulation, especially the adaptive regulation, has proved to be challenging under the sudden change of inlet velocity. In this paper, we report a novel method that significantly improves combustion performance, including heat transfer enhancement under steady-state conditions and adaptive stable flame regulation under velocity sudden increase. We successfully harnessed the synergistic benefits of both the front and rear baffles, investigated the angle matching of the baffles at various inlet velocities, and employed nitinol memory metal as the baffle material to examine its impact on enhancing heat transfer and flame control behavior. According to the results, under the synergic action, the combustion efficiency reaches to 96.92%, and the baffle angle matching 60° + 30° shows good combustion performance at medium-low velocity, and a flame breaking limit of 92 m/s is obtained at 0° + 0° with high-velocity condition. In addition, nitinol alloy is selected as the deformation baffle material, the flame breaking limit is further extended by 6 m/s, and the combustion efficiency can still be maintained at 0.45 ms by a velocity sudden increment of 60 m/s, and the pressure loss is reduced by more than 70%. This study is helpful to provide a reference for the steady combustion under the sudden change of micro-scale conditions, and provides a new idea for the adaptive control of flame.