Autoignition Dynamics of N-dodecane Droplets under Normal Gravity. Issue 9 (4th July 2022)

• Record Type: Journal Article
• Authors: Rose, Evan N.; Nayagam, Vedha; Dietrich, Daniel L.; Hicks, Michael C.; Hegde, Uday G.; Padilla, Rosa E.; Williams, Forman A.
• Is Part Of: Combustion science and technology. Volume 194:Issue 9(2022)
• Page Start: 1830
• Page End: 1849
• Publication Date: 2022-07-04
• Subjects: two-stage ignition -- autoignition -- droplet combustion; Combustion -- Periodicals; Combustion engineering -- Periodicals; 541.36105
• DOI: 10.1080/00102202.2020.1840369
• Languages: English
• ISSNs: 0010-2202

Abstract

ABSTRACT: Experimental observations of two-stage autoignition dynamics of fiber-supported normal dodecane droplets in air under normal gravity are presented for a range of pressures and temperatures. High-speed shadowgraph imaging of the autoignition process reveals cool-flame and hot-flame front-formation and propagation dynamics. During two-stage ignition, a cool-flame kernel is first formed below the droplet; it then propagates toward the droplet along the fuel-vapor plume, and subsequently a hot-flame kernel is established behind the cool-flame front which rapidly expands, engulfing the droplet and establishing the classical diffusion flame. Results for the cool-flame and hot-flame kernel locations and their propagation speeds are presented for a range of ambient pressures, varying between normal atmospheric pressure and super-critical pressures and temperatures.