A MULTI-FLUID MODEL COUPLED WITH INTERFACE TRACKING METHOD FOR SIMULATION OF LIQUID JET BREAKUP

For liquid jet breakup, when small drops are fragmented from the surface of jet, the fluid's interfaces with various length scales will coexist in the flow regimes. The paper presents a coupled method to simulate liquid jet breakup. The present method is based on Yan and Che's strategy which has been proven to be capable for simulation of bubbly-slug flow. In the method, the basic multi-fluid model and interface tracking method are coupled by a unified solution frame work of MCBA-SIMPLE algorithm. The jet phase and continuous liquid phase are combined into a continuous phase in order that the large-scale interface of jet can be reconstructed by VOF/PLIC method. The coupled model consists two sub-models, the model based on VOF method and the conventional multi-fluid model; The relationships and switching of the sub-models are disused and summarized in the paper. Some cases are presented to show the capabilities of the current method. Firstly, the sub-model which is equivalent to the VOF method is used to simulate the interface behavior during the jet breakup and a breakup length equation is correlated. Then the coupled model is applied to the same simulation. A simple jet breakup model is used to simulate mass transfer of drops from jet. Variation of the drop surface area is considered by solving a transport equation. The simulation results preliminarily show that the current method is capable to simulate the complex jet breakup process. The main characteristics of the process such as breakup length and drops distribution are reasonably simulated.