CFD prediction of the trajectory of a liquid jet in a non-uniform air crossflow

Abstract

This paper describes a predictive numerical modelling methodology for calculation of deflection and deformation of liquid jets in air crossflows. The methodology combines Jet Embedding (JE) with Volume-of-Fluid (VOF) in a computational fluid dynamics (CFD) based approach. The combined JE/VOF methodology applies the JE concept of modelling the air and liquid phases in separate but linked models, with a representation of the liquid column embedded in the crossflow model. The crossflow is modelled in a CFD calculation using CFX4.2 and the separate jet model is written in FORTRAN 77. A multi-fluid implementation of the VOF technique, in CFX4.2, is used to model deformation of the liquid column cross-section in a series of two-dimensional models along the column trajectory. The crossflow, jet and deformation calculations are linked by an iterative procedure which advances from the nozzle exit in a series of time-steps. The JE/VOF methodology is used to make a prediction of a time-average trajectory of a deflected liquid column, with a progressively deformed cross-section, in an air crossflow. The prediction demonstrates that the JE/VOF methodology is capable of producing a physically realistic result.