A novel Swiss-roll counterflow micro-combustor: Experimental investigation of flame dynamic characteristics by spectroscopy and RGB image processing methods

Abstract

In this study, a novel Swiss roll counterflow micro-combustor is developed to improve flame stability, preheating, and heat recovery. The study experimentally investigates the combustion characteristics of methane-oxygen mixtures in a constant-temperature aluminum chamber over a range of equivalence ratios using spectroscopic methods and RGB image processing. The results indicate that this micro-combustion flame is a cool flame with an inverse relationship between variations of flame thickness and flame length. Furthermore, the study explores the behavior of some radicals, including OH*, CH*, C2* , H2O*, and CO2* and their radiation intensity, which are influenced by the equivalence ratio and mass flow rate of fuel to the oxidizer, as well as other factors such as flame surface area and heat transfer from the wall. RGB image processing is also utilized to investigate the changes of CH* and C2* in channels G and B, respectively. The study shows a strong correlation between the visible light intensity of the flame and the R channel. The results demonstrate that for the equivalence ratios Between 1.93 and 2.26, the radiation intensity of the radicals is relatively stable, which makes it applicable for micro-combustors.