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Modeling and simulation of primary jet breakup at aircraft engine relevant conditions

飞机发动机相关条件下射流一次破裂的建模与仿真

基本信息

批准号：
211040440
负责人：
Professor Dr.-Ing. Johannes Janicka
金额：
--
依托单位：
Fachgebiet Energie- und Kraftwerkstechnik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/211040440?language=en
关键词：
Modeling simulation primary jet breakup

项目摘要

The main goal of the second term of the project is the development of a method to predict the primary breakup of liquid fuel in a realistic airblast atomizer geometry using embedded DNS. The embedded DNS (eDNS) was introduced in the first term of the project and refers to a method in which the primary breakup is computed without underlying simplifying assumptions using a Direct Numerical Simulation (DNS) which is embedded in a Large-Eddy-Simulation (LES) of the whole airblast atomizer. The usage of the computationally expensive DNS is therefore reduced to the most important regions which enables the usage of DNS for realistic technical applications. In the first term of the project, the method was successfully employed to compute a generic geometry. Detailed comparison showed a good agreement of the predicted primary breakup to experimental data. The proposed project will compute the primary breakup at the atomizing edge of a real airblast atomizer. The droplet distributions at aircraft engine relevant conditions are extracted, enabling the transformation in to the Euler-Lagrange description for the subsequent simulation of the combustion, which is not part of the proposed project. The objectives of the work are to generate boundary conditions of the embedded domain (LES of the atomizer), an enhanced resolution of the phase interface through a coupling of VOF- and Level-Set method and the eDNS of the primary breakup. The work of the first term has shown that the complete resolution of the liquid mass is not feasible due to the large proportion of especially small droplets. The two objectives to reconstruct the non-resolved droplets and to evaluate the quality of the reconstruction method follow from this. Another objective is to analyse the physical breakup mechanism, which originate the primary breakup. The work of the second term enables the very first detailed insight into the primary breakup of a realistic airblast atomizer geometry at realistic operating conditions. The gained insights will contribute to significantly improve the capabilities to predict combustion chambers of aircraft engines.

该项目的第二个学期的主要目标是开发一种方法来预测液体燃料在一个现实的空气雾化喷嘴几何形状，使用嵌入式DNS的主要破碎。嵌入式DNS（eDNS）是在项目的第一个学期引入的，是指一种方法，在该方法中，使用直接数值模拟（DNS），这是嵌入在大涡模拟（LES）的整个气流雾化器的主要破碎计算没有潜在的简化假设。因此，计算上昂贵的DNS的使用被减少到最重要的区域，这使得能够将DNS用于现实的技术应用。在项目的第一学期，该方法被成功地用于计算通用几何。详细的比较表明，预测的初级破碎的实验数据吻合得很好。本计画将计算真实的空气雾化喷嘴雾化边缘的一次破碎。在飞机发动机相关条件下的液滴分布被提取，从而能够转换为欧拉-拉格朗日描述，用于随后的燃烧模拟，这不是拟议项目的一部分。工作的目标是生成嵌入域的边界条件（LES的雾化器），通过耦合VOF-和Level-Set方法和eDNS的初级破碎相界面的分辨率提高。第一项的工作已经表明，由于特别小的液滴的大比例，液体质量的完全分辨率是不可行的。重建未分辨液滴和评估重建方法的质量的两个目标由此而来。另一个目的是分析物理破碎机制，导致初级破碎。第二项的工作，使第一个详细的洞察到一个现实的空气雾化喷嘴几何形状在现实的操作条件下的主要分裂。所获得的见解将有助于显着提高预测航空发动机燃烧室的能力。