Browse Publications Technical Papers 2000-01-1249
2000-03-06

Cavitation in Real-Size Multi-Hole Diesel Injector Nozzles 2000-01-1249

A production six-hole conical sac-type nozzle incorporating a quartz window in one of the injection holes has been used in order to visualize the flow under cavitating flow conditions. Simultaneous variation of both the injection and the back chamber pressures allowed images to be obtained at various cavitation and Reynolds numbers for two different fixed needle lifts corresponding to the first- and the second-stage lift of two-stage injectors. The flow visualization system was based on a fast and high resolution CCD camera equipped with high magnification lenses which allowed details of the various flow regimes formed inside the injection hole to be identified. From the obtained images both hole cavitation initiated at the top inlet corner of the hole as well as string cavitation formed inside the sac volume and entering into the hole from the bottom corner, were identified to occur at different cavitation and Reynolds numbers. Comparison of the cavitation images obtained in the real size nozzle with those obtained in an enlarged fully transparent acrylic nozzle replica has confirmed that similar flow regimes may form inside the injection hole of real size and large scale injectors. Despite the similarity in the macroscopic cavitation structures that were found to depend on cavitation intensity, the transient development of cavitation bubbles was identified to be different inside the two nozzles due to the different residence and life time of the moving bubbles. Based on the flow similarity between the real size and enlarged multi-hole nozzles and previous extensive experience on the cavitating flow characteristics in large scale nozzles, better understanding of the cavitating flow in real size nozzles operating under Diesel engine conditions has been obtained, which can guide the development of relevant computer models.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

A Hydro-Mechanical Simulation of Diesel Fuel Injection Systems

870432

View Details

TECHNICAL PAPER

Coupled 1D-3D Simulation of Common Rail Injector Flow Using AVL HYDSIM and FIRE

2009-24-0029

View Details

TECHNICAL PAPER

Neural-Network Based Approach for Real-Time Control of BMEP and MFB50 in a Euro 6 Diesel Engine

2017-24-0068

View Details

X