Study of the influence of the needle lift on the internal flow and cavitation phenomenon in diesel injector nozzles by CFD using RANS methods
Study of the influence of the needle lift on the internal flow and cavitation phenomenon in diesel injector nozzles by CFD using RANS methods
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DOI：
10.1016/j.enconman.2012.10.011
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发表时间：
2013-02-01
影响因子：
10.4
通讯作者：
De Alfonso, C.
中科院分区：
文献类型：
--
作者：
Salvador, F. J.;Martinez-Lopez, J.;De Alfonso, C.
柴油机喷油嘴内的空化现象对喷油过程中的内部流动和喷雾发展有着重要的影响。然而，它对流动的影响，在针打开和关闭仍然不清楚，由于巨大的困难，在部分针lifest.In本文中，进行了扩展的计算研究，在多孔喷嘴建模10个不同的固定针升降机。内部流动已被建模与连续喷嘴流模型，认为空化流作为一个均匀的混合物的液体和蒸汽。由于雷诺数较高，采用RNG k-k模型的RANS方法考虑了湍流效应。首先，在全升力条件下，从质量流量、动量通量和有效速度方面对程序进行了验证，结果表明程序与实验结果吻合得很好。一旦程序得到验证，可以深入研究喷嘴内部流动及其在不同部分针阀升程下出口处的特性。然而，不仅解释了主要的流动特征，而且空化的出现和湍流的发展，这在不同的针升程模拟之间呈现出巨大的差异。(C)2012爱思唯尔有限公司保留所有权利。
It is well known that cavitation phenomenon in diesel injector nozzles has a strong influence on the internal flow during the injection process and spray development. However, its influence on the flow during needle opening and closing remains still unclear due to the huge difficulties related to performing experiments at partial needle lifts.In this paper, an extended computational study has been performed in a multi-hole nozzle modeling 10 different fixed needle lifts. The internal flow has been modeled with a continuum nozzle flow model that considers the cavitating flow as a homogeneous mixture of liquid and vapour. Due to high Reynolds numbers, turbulence effects have been taken into account by RANS methods using a RNG k-epsilon model.Firstly, the code has been validated against experimental data at full needle lift conditions in terms of mass flow, momentum flux and effective velocity, showing a fairly good agreement with experimental results.Once the code has been validated, it has been possible to study in depth the internal nozzle flow and its characteristics at the outlet at different partial needle lifts. Nevertheless, not only the main flow features have been explained, but also the cavitation appearance and the turbulence development, which present huge differences between the different needle lifts simulated. (C) 2012 Elsevier Ltd. All rights reserved.