Influence of the parallel oil‐secondary air and F‐layer secondary air distribution on the flow, combustion, and NOx generation characteristics of FW down‐fired boilers retrofitted with a stable combustion technology. - Du, He; Li, Zhengqi; Liu, Zheng; Zhang, Mingdi; Chen, Zhichao; Song, Jian; Fang, Fan; Xiao, Ronghua (Asia-Pacific Journal of Chemical Engineering, 2022)