Experimental study on MILD combustion of methane under non-preheated condition in a swirl combustion furnace

In this paper, a swirl combustion furnace is designed and manufactured to realize MILD combustion. The influence of swirling air proportion, equivalence ratio and thermal power on MILD combustion are studied. The results reveal that the combustion chamber temperature is highest and the NO and CO emissions are lowest when the proportion of swirling air is 100%. Additionally, an appropriate equivalence ratio increases the combustion chamber temperature while reducing the NO and CO emissions during MILD combustion. Furthermore, CO emissions reach their minimum at a specific thermal power, while the temperature and NO emissions increase with thermal power. Overall, MILD combustion exhibits high stability under all experimental conditions, with NO emissions consistently below 30 ppm. Indeed, the findings underscore that the swirl combustion furnace is capable of achieving MILD combustion with superior combustion performance. This highlights the considerable potential of the combustion furnace for various applications, especially in areas where efficient and clean combustion is paramount.