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| Experiment on Characteristics of Cavitation and Erosion in Diesel Engine Nozzle Orifice |
| DOI：10.13949/j.cnki.nrjgc.2018.05.003 |
| Key Words:cavitation cavitation erosion diesel engine nozzle hole visualization test |
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| Abstract:Based on the cavitation erosion test of a real injector, the micro cavitation erosion in the injector nozzle was detected by X-ray CT scanning. To obtain the specific influence of cavitation on erosion, special attention was made on the characteristics of cavitating flow and cavitation erosion in a simplified rectangle nozzle orifice based on a self circulation visualization experimental setup that can obtain cavitation area, erosion area and morphology at the same time as well as with a high-speed digital camera and the scanning electronic microscopy technology (SEM). The results show that with the increase of injection pressure, cavitation grows more intensely, and four different flow states appear in succession: single-phase flow, incomplete cavitating flow, super cavitating flow, and hydraulic flip. The cloud cavitation shedding shows a certain cyclic periodicity. The cavitation erosion region at the downstream of the nozzle orifice appears in the area of cloud cavitation shedding and collapsing, and the cavitation erosion phenomenon exists at the junction of cavitation and liquid phase. It can be reasoned from the results that the cloud cavitation shedding and collapsing as well as condensation collapsing are two main factors of cavitation erosion. |
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