Injector: VOF, 2-Phase Flow

Multi-Phase Flow in an Injector (Two-Phase VOF Model) — ANSYS Fluent CFD Simulation

Description

Welcome to the Injector CFD Simulation module. This project introduces the fundamentals of multiphase flow analysis within fuel injectors — a critical component across combustion systems in automotive, aerospace, and energy applications. You'll use the Volume of Fluid (VOF) multiphase model in ANSYS Fluent to simulate and interpret the complex fluid interactions inside an injector, capturing the dynamic interface between the liquid fuel and the surrounding gas within the injector's confined internal geometry. Within the Mechanical Engineering: Beginner CFD Training Package, this project opens the multiphase group, introducing the intuitive VOF interface-tracking approach before the more advanced Eulerian cases that follow.

Methodology

The simulation works from a pre-configured injector model, with a mesh designed to resolve the liquid–gas interface within the injector's narrow internal passages. The boundary conditions define realistic operating conditions — appropriate pressure, velocity, and fluid-property settings at the fuel inlet, together with a proper representation of the surrounding gas phase and the injector wall boundaries. The heart of the setup is the VOF configuration: the scheme is selected and tuned for stable, accurate interface capture within the complex internal geometry, and surface tension and turbulence effects are incorporated to govern the fluid behavior during injection. The case is solved as a steady-state simulation.

Analysis

Post-processing develops your ability to read multiphase behavior through contours and animations showing the spatial distribution of liquid fuel and gas, alongside a quantitative assessment of velocity profiles, pressure distributions, and the spray characteristics at the nozzle exit. From these results you can examine how injection pressure influences the flow behavior and phase distribution, evaluate injector efficiency, flow uniformity, and potential cavitation risk, and see how the findings can guide nozzle-geometry optimization to improve atomization and spray quality. By the end of this project, you'll be able to set up and run an injector simulation using the VOF model in ANSYS Fluent, interpret the results for flow characteristics and phase distribution, and apply these insights to broader multiphase engineering problems — forming a solid foundation for further study in combustion systems, spray dynamics, and fuel-injection technology.