CHARACTERISTICS OF HOLLOW CONE SPRAYS IN CROSSFLOW

Abstract

A qualitative and quantitative study of a hollow cone spray exposed to a cross-flowing stream of air is presented, based on the conventional Lagrangian-Eulerian point parcel spray treatment. The flow solver employs the open source library of computational mechanics solvers of OpenFOAM. Globally, the spray can be categorized by a near- and far-field region, where the demarcation makes use of the magnitude of the individual droplet drag force. In the near field the vertical spray momentum largely dominates the gas flow momentum and forces it to bend downward. Within this near field we show that two conditions−weak crossflow and strong crossflow−can be identified, depending upon the strength of crossflow in relation to the induced air motion. While this is in agreement with Ghosh and Hunt (1998), we differ in the approach taken and the spray geometry studied. In the case of a weak crossflow, the spray severely deflects the crossflow streamlines, forcing the lee side streamlines to converge toward the center of the spray. In the case of a strong crossflow, the streamlines are deflected; nevertheless, they penetrate the spray. This has a significant impact on the topology of the spray structure, which has not been previously presented. In the far field the center streamline of the spray-induced air jet agrees extremely well with a single-phase jet trajectory. This behavior is shown to be independent of grid resolution and of atomization model.