Hydrodynamic Cavitation in the Fuel Injector Nozzle and its Effect on Spray Characteristics: A Review

Abstract

The performance of internal combustion engines can be improved by optimizing fuel spray characteristics. However, high injection pressures and small nozzle diameters in modern fuel injectors result in cavitation flows inside the nozzle, making it difficult to accurately characterize vapor bubble formation and growth. In this review, we explore the influence of cavitation flow on spray formation and examine the effects of geometric and operational factors. We discuss the experimental techniques used to generate a cavitation map and the mathematical models used to describe the behavior and magnitude of the bubble. We also investigate the impact of cavitation on spray properties, including the enhancement of liquid jet fragmentation due to the collapse of cavitation bubbles near the nozzle output. We present a multidimensional cavitation-coupled spray model and discuss the effect of cavitation on spray angle. While experimental work is effective, theoretical analysis can also provide insights into the impact of cavitation flow on spray characteristics. Our review concludes that the spray angle increases during the growing cavitation and super cavitation regimes, but decreases significantly following the cavitation flip. The string cavitation is observed when the position of the needle valve shifts or at a lower needle lift and the spray cone angle increases significantly. Overall, this review provides an inclusive overview of cavitation flow and its influence on spray formation and will aid in the development of more efficient internal combustion engines.

Keywords

• hydrodynamic cavitation
• fuel injector nozzle
• spray formation
• cavitation induced spray
• string cavitation