Options
Breakup dynamics in a twin-jet crossflow airblast atomizer
Date Issued
01-01-2020
Author(s)
Patil, Shirin
Indian Institute of Technology, Madras
Abstract
Airblast atomizers with radial injection of liquid fuel jets into annular crossflow of air find applications in gas turbine combustion, for instance, in Lean Premixed Prevaporized (LPP) combustors. Though significant research has been conducted on atomization of single liquid jet in crossflow air (typically in rectangular wind tunnels), the hole-to-hole variation in jet breakup in a multi-jet configuration has received less attention. The current research considers an airblast atomizer, which allows injection of two radially opposite liquid jets of water from a central tube into swirling and non-swirling annular crossflow of air. The atomizing characteristics of the two liquid jets could be simultaneously studied based on high speed visualization. Experiments were performed for a range of aerodynamic Weber number (Weg) and liquid Reynolds number (ReL) that ensured jet-wall interactions are always avoided before the jet breakup. Interestingly, differences in the left and right jets are observed not only in the instantaneous jet breakup length but also the modes of jet breakup (either column or bag modes). The mean and the fluctuations of jet breakup length were measured. Proper Orthogonal Decomposition (POD) analysis of the jet breakup images was carried out to identify the dominant jet breakup modes and also to investigate any temporal correlation between the breakup modes of the left and the right jets. The effect of addition of air swirl on the dynamics of liquid jet breakup was also investigated.