喷嘴空化模型建立与有效性试验验证

发布时间：2018-08-22 16:26

【摘要】：提出了一种针对喷嘴孔内空化现象的数值计算模型——喷嘴空化模型,并进行了可视化试验以验证其模型有效性,其中喷嘴空化模型考虑了液相与气相之间相变、气泡动力学、湍流扰动及不凝性气体影响等诸多因素,并采用喷孔内空化数对相变速率方程进行了修正。将基于喷嘴空化模型的数值计算结果与试验结果及基于Schnerr-Sauer模型的计算结果进行对比分析,结果显示:在2种空化模均采用默认参数的前提下,喷嘴空化模型与Schnerr-Sauer模型计算所得喷孔内空化现象变化趋势均与试验结果吻合良好,即喷嘴孔内空化现象随喷射压力提高而加强,且在发展空化至超空化流态过渡过程中空化特征长度涨幅远高于其他流态过渡情况;喷嘴空化模型计算所得空化特征长度在各流态下均与试验结果吻合良好,Schnerr-Sauer模型计算空化特征长度则低于试验结果,两者与试验值的最大误差均发生在超空化阶段,其中喷嘴空化模型计算值为试验值的92%,Schnerr-Sauer模型计算值为试验值的65%。该结果表明,所建立喷嘴空化模型可用于较为准确地模拟喷嘴孔内空化现象的变化趋势及空化特征长度。
[Abstract]:In this paper, a numerical model of cavitation in nozzle orifices, the cavitation model of nozzles, is proposed, and a visual experiment is carried out to verify the validity of the model. The cavitation model of nozzle considers the phase transition between liquid phase and gas phase, bubble dynamics. Some factors, such as turbulence disturbance and the influence of noncondensable gas, were used to modify the phase change rate equation by using cavitation number in the nozzle. The numerical results based on the nozzle cavitation model are compared with the experimental results and the results based on the Schnerr-Sauer model. The results show that the default parameters are used in the two cavitation models. The cavitation phenomena in the nozzle cavity calculated by both the nozzle cavitation model and the Schnerr-Sauer model are in good agreement with the experimental results, that is, the cavitation phenomenon in the nozzle hole is enhanced with the increase of the injection pressure. The length of the hollow characteristic in the transition from cavitation to supercavitation is much higher than that in other flow states. The calculated cavitation characteristic length of the nozzle cavitation model is in good agreement with the experimental results in each flow state. The calculated cavitation characteristic length of Schnerr-Sauer model is lower than that of the experimental results, and the maximum error between the two models and the experimental values occurs in the supercavitation stage. The calculated value of the nozzle cavitation model is 92% of the experimental value, and the calculated value of Schnerr-Sauer model is 65% of the experimental value. The results show that the cavitation model can be used to simulate the variation trend of cavitation phenomenon and the characteristic length of cavitation.
【作者单位】：吉林大学汽车仿真与控制国家重点实验室;
【基金】：国家自然科学基金项目(51306069)
【分类号】：O35

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