A Spray angle of liquid-liquid Ejector CFD simulation is a computer model of a device that uses one liquid to pump and mix another. These ejectors, also called jet pumps, are important in many industries for processes like chemical mixing and wastewater treatment. The Spray CFD analysis helps engineers understand how the two liquids interact. To do this, we use a special method called the Volume of Fluid (VOF) model in ANSYS Fluent. The Spray angle of liquid-liquid Ejector VOF CFD simulation is critical because the angle of the spray shows how well the two liquids are mixing. A good Ejector Performance Simulation helps engineers design devices that are more efficient and effective. This type of Two-Phase Flow Modeling Fluent is essential for accurately predicting the behavior of two liquids that do not mix, like oil and water.

• Reference [1]: Cheng, Peng, et al. “On the prediction of spray angle of liquid-liquid pintle injectors.” Acta Astronautica138 (2017): 145-151.

Figure 1: The 2D axisymmetric geometry of the Liquid-Liquid Ejector CFD model, showing the primary nozzle, suction chamber, and mixing tube. [1]

Simulation process: Fluent VOF Setup, Transient 3-Phase Multiphase Modeling

To perform this 3-Phase VOF Model study, we first created a 2D axisymmetric geometry that represents a simplified liquid rocket injector. We then generated a high-quality structured quadrilateral mesh. We made the mesh cells much finer near the injector outlet and in the downstream mixing region. This mesh refinement is critical for accurately capturing the thin interface between the three different fluids in a Multiphase Interface Tracking simulation. In the ANSYS Fluent software, the most important physics model was the Volume of Fluid (VOF) model, which was set up to handle three different Eulerian phases. Phase 1 was defined as liquid kerosene, Phase 2 was liquid dinitrogen tetroxide, and Phase 3 was air.

Figure 2: The high-quality structured mesh with refinement near the nozzle exit and mixing zones for accurate Interface Tracking CFD.

Post-processing: CFD Analysis, Jet Breakup and Fuel-Oxidizer Interaction

The phase fraction contours in Figure 3 show the direct result of the complex, three-phase fluid interaction. From an engineering perspective, these contours reveal the fundamental process of primary jet breakup. We can clearly see the central jet of kerosene (red) penetrating the surrounding dinitrogen tetroxide (green). The initial air in the chamber (blue) is pushed aside by the propellants. Critically, the interface between the kerosene and the dinitrogen tetroxide is not a smooth, straight line. Instead, it shows wavy instabilities and the formation of ligaments. These are the very first signs of the jet breaking apart into smaller droplets, a process called atomization.

Figure 3: A phase fraction contour from the VOF Fluent simulation, showing the interface between the primary liquid (kerosene, red) and secondary liquid (water, blue), clearly defining the spray cone.

The velocity contour in Figure 4 explains the physics causing this breakup. The high-velocity kerosene jet creates strong shear forces as it moves past the slower-moving dinitrogen tetroxide. This shearing action is what pulls on the surface of the jet, creating the instabilities seen in Figure 3. The simulation successfully captures how the jet’s momentum is transferred to the surrounding oxidizer, initiating the mixing process. The ability of the model to show these small, highly features is proof of its accuracy. This detailed insight into how the jet deforms and starts to break up is exactly the information engineers need to predict combustion efficiency and stability inside a real rocket engine. The most important achievement of this simulation is its successful use of a three-phase VOF model to capture the highly unstable interface dynamics between a kerosene fuel jet and a dinitrogen tetroxide oxidizer, correctly modeling the initial ligament formation that precedes full atomization and hypergolic ignition.

Figure 4: A velocity contour from the Propulsion System CFD analysis, showing the high-speed kerosene jet and the surrounding fluid motion.