Fuel spray atomization process which is affected by a flow inside a nozzle

The high pressure injection systems are commonly used in internal combustion engines. Injected fuel forms a spray and it determines efficiency and emissions of the engines. In spite of the importance of the spray development, the physical processes of it especially in near field of the nozzle are only understood in a part of it, due to the complex combination of phenomena. Common known measurement techniques are almost impossible to obtain the information about atomization characteristics in near nozzle, because of the small dimensions (< 100 µm), the short injection duration (< 1 ms) and the dense spray (c.a. 100000 droplets in 1 mm³).  Therefore, an advanced laser measurement technique which has micro-scale probe volume and ultra-high speed sampling rate (GHz) are under developing. The technique leads us to know about the spray droplet characteristics. The characteristics are affected by the phenomena inside nozzle for example cavitation and turbulence. To be determining the effect of these phenomena to the atomization process, numerical simulations of flow inside nozzle are done in parallel to the experiments.