Breakup modeling of a liquid jet in cross flow

Abstract

We propose a novel breakup model to simulate the catastrophic breakup regime in a supersonic cross flow. A developed model has been extended from an existing Kelvin-Helmholtz/Rayleigh-Taylor (K-H/R-T) hybrid model. A new mass reduction rate equation, which has critical effects on overall spray structure, is successfully adopted, and the breakup length, which is an important parameter in existing model, is replaced by the breakup initiation time. Measured data from the supersonic wind tunnel with a dimension of 762×152×127 mm was employed to validate the newly developed breakup model. A nonaerated injector with an orifice diameter of 0.5 mm is used to inject water into a supersonic flow prescribed by the momentum flux ratio of the liquid jet to free stream air, q 0 . The conservation-element and solution-element (CE/SE) method, a novel numerical framework for the general conservation law, is applied to simulate the supersonic compressible flow. The spray penetration height and average droplet size along with a spray penetration axis are quantitatively compared with data. The shock train flow structures induced by the presence of a liquid jet are further discussed.

Evaluation of natural and tracer fluorescent emission methods for droplet size measurements in a diesel spray

“…More complete atomization is expected at the same location due to higher aerodynamic forces for the higher injection pressure as higher velocities would enhance droplet breakup (Im et al 2011, Soare 2007). Higher atomization level mainly results in lower droplet diameter for higher injection pressure as referenced by the y-axes on figure 10.…”

Eulerian–Lagrangian method for liquid jet atomization in supersonic crossflow using statistical injection model

“…In previous studies, an average droplet size and distribution have been used to simulate injected droplets. 1,17,18 However, strong turbulence structures will develop inside the injector at high-speed flow condition, the average droplet size and distribution are no longer reasonable. 32 Furthermore, the droplet sizes of injected parcels are strongly dependent on atomizer configurations.…”

“…One of the most important and difficult measurements in the high-speed crossflow is the cross-sectional droplet distribution along the flow direction, because it is directly related to the mixing process and eventually the combustion performance. 18 Results shown in Figure 7 refer to all droplets contained in a slice with…”

Numerical simulations of spray jet in supersonic crossflows using an Eulerian approach with an SMD model

“…However, it should be noted that many of the numerical works have been performed on the liquid jet in a co-flowing gas stream or liquid injection into a quiescent gas, typically for diesel applications ( Iyer and Abraham, 20 03;Khosla and Crocker, 20 04;Lin et al, 2014;Navarro-Martinez, 2014;Devassy et al, 2015 ). The existing numerical works of the liquid jets in crossflow are limited, and rarely concerned with the supersonic regimes ( Rachner et al, 2002;Balasubramanyam and Chen, 2008;Im et al, 2011 ). The wide range of length and time scales may account for the difficulties here.…”