Injection Spray Dynamics
- Steve Lottes -
Computational Fluid Dynamics Project Leader
- Tanju Sofu -
Simulation, Modeling, and Analysis Leader
The fuel-injection process in modern engines is a critical step to attaining high thermal efficiency and emissions control.
Accurate control of the injection performance parameters (timing, delivery, instantaneous flow rate, pressure, spray configuration,
etc.) offers one of the most effective means of influencing mixture preparation and combustion kinetics to achieve both clean-burning
and high thermodynamic efficiency. Modern fuel-injection equipment provides better control of timing and delivery at much higher
injection pressures, resulting in improved diesel engine performance and fuel economy. Unfortunately, direct evaluation of the
actual fuel-injection spray is still difficult, and fine-tuning of the injection system is a trial-and-error procedure. Researchers
need a new, more powerful means to study and evaluate the characteristics of sprays from fuel injectors so that they can further
improve the mixing and combustion processes.
Role of High-Performance Computing
Modeling of sprays is an evolving technology based on the fundamentals of fluid dynamics and multiphase flow. Breakup of a
spray, transport of the spray material, and interaction of the spray particles with the boundary and other spray particles can
be described with the basic equations of fluid mechanics, but they are significantly complicated by the effects of multiple free
surfaces and particle-to-particle interactions. For combustion, the inclusion of chemical reactions inside the droplets and at
their surfaces further complicates the physical picture. Nonetheless, mathematical and computational models of the droplet breakup
processes and transport are being developed. These computational models are often three-dimensional and time-dependent, requiring
large computational resources to facilitate the analysis.
|Fuel injector performance and efficiency can be assessed with
fluid dynamics methods, such as fluid interface tracking.