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针对柴油机喷射压力日渐增加及喷孔愈趋微细化背景下的喷嘴内部空化流动问题,基于大涡模拟(Large Eddy Simulation,LES)及混合均相流(Homogeneous Equilibrium Mixture,HEM)模型,对高压微细喷孔内空化流动进行了多维数值模拟研究。根据喷孔内部不同区域的流动的敏感性,运用变阿格技术建立了1/4喷嘴计算模型,并采用E.Winklhofer试验结果验证了数学模型的合理性。结果得出:超高喷射压力及微细喷孔条件下,喷孔内部空化层的演变速度极快;孔内空泡的溃灭过程促进了湍流涡团量的增加,内部湍流涡团密集区域与空化区域一致;小孔径下喷孔内部空化区域更为明显,空泡在出口处溃灭产生的流体微射流增强了出口处的湍流扰动强度,与内部空化的共同作用下有利于改善燃油的雾化质量。
In order to solve the problem of cavitation flow inside the nozzle under the condition of increasing injection pressure of the diesel engine and finer injection hole, based on the Large Eddy Simulation (LES) and the Homogeneous Mixture (HEM) model, The multi-dimensional numerical simulation of the cavitation flow in the fine hole was carried out. According to the sensitivity of the flow in different regions inside the nozzle hole, a 1/4 nozzle model was established by using the variable Arg technology. The validity of the mathematical model was verified by the E.Winklhofer test. The results show that under the conditions of ultra-high injection pressure and fine orifice, the evolution of cavitation layer inside the orifice is very fast. The collapse process of cavitation in the orifice promotes the increase of turbulent eddy mass, Which is consistent with the cavitation area; the cavitation area inside the orifice is more obvious under the small aperture, and the microfluid of the fluid produced by the collapse of the bubble at the outlet enhances the turbulence disturbance intensity at the outlet, which is beneficial to the interaction with the internal cavitation Improve the quality of fuel atomization.