• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >The dynamics of turbulent premixed flames: Mechanisms and models for turbulence-flame interaction.
【24h】

The dynamics of turbulent premixed flames: Mechanisms and models for turbulence-flame interaction.

机译：湍流预混火焰的动力学：湍流与火焰相互作用的机理和模型。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The use of turbulent premixed combustion in engines has been garnering renewed interest due to its potential to reduce NOx emissions. However there are many aspects of turbulence-flame interaction that must be better understood before such flames can be accurately modeled. The focus of this dissertation is to develop an improved understanding for the manner in which turbulence interacts with a premixed flame in the 'thin flamelet regime'. To do so, two new diagnostics were developed and employed in a turbulent slot Bunsen flame. These diagnostics, Cinema-Stereoscopic Particle Image Velocimetry and Orthogonal-Plane Cinema-Stereoscopic Particle Image Velocimetry, provided temporally resolved velocity and flame surface measurements in two- and three-dimensions with rates of up to 3 kHz and spatial resolutions as low as 280 mum.;Using these measurements, the mechanisms with which turbulence generates flame surface area were studied. It was found that the previous concept that flame stretch is characterized by counter-rotating vortex pairs does not accurately describe real turbulence-flame interactions. Analysis of the experimental data showed that the straining of the flame surface is determined by coherent structures of fluid dynamic strain rate, while the wrinkling is caused by vortical structures. Furthermore, it was shown that the canonical vortex pair configuration is not an accurate reflection of the real interaction geometry. Hence, models developed based on this geometry are unlikely to be accurate.;Previous models for the strain rate, curvature stretch rate, and turbulent burning velocity were evaluated. It was found that the previous models did not accurately predict the measured data for a variety of reasons: the assumed interaction geometries did not encompass enough possibilities to describe the possible effects of real turbulence, the turbulence was not properly characterized, and the transport of flame surface area was not always considered. New models therefore were developed that accurately reflect real turbulence-flame interactions and agree with the measured data. These can be implemented in Large Eddy Simulations to provide improved modeling of turbulence-flame interaction.
机译：由于在发动机中使用湍流预混燃烧具有减少NOx排放的潜力，因此引起了新的兴趣。但是，湍流-火焰相互作用的许多方面都必须得到更好的理解，然后才能对此类火焰进行精确建模。本文的重点是发展对湍流与“薄小火焰态”中的预混火焰相互作用的方式的更好理解。为此，开发了两个新的诊断程序，并将其用于湍流的本生火焰中。这些诊断程序（电影院立体粒子影像测速法和正交平面电影院立体粒子影像测速仪）提供二维和三维的时间分辨速度和火焰表面测量，速率高达3 kHz，空间分辨率低至280 mum通过这些测量，研究了湍流产生火焰表面积的机理。已经发现，先前的以火焰反向旋转为特征的火焰拉伸概念并不能准确地描述真实的湍流-火焰相互作用。对实验数据的分析表明，火焰表面的应变是由流体动力应变率的相干结构决定的，而起皱是由涡旋结构引起的。此外，已经表明，规范涡对构型不是真实相互作用几何的准确反映。因此，基于这种几何形状开发的模型不太可能是准确的。评估了以前的应变率，曲率拉伸率和湍流燃烧速度模型。结果发现，先前的模型由于多种原因不能准确地预测所测得的数据：假定的相互作用几何结构没有足够的可能性来描述真实湍流的可能影响，湍流没有得到适当的表征，以及火焰的传输并非总是考虑表面积。因此，开发了新模型，该模型可以准确反映实际的湍流-火焰相互作用，并与实测数据一致。这些可以在“大涡模拟”中实现，以提供对湍流-火焰相互作用的改进建模。

著录项

  • 作者

    Steinberg, Adam M.;

  • 作者单位

    University of Michigan.;

  • 授予单位 University of Michigan.;
  • 学科 Engineering Aerospace.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 281 p.
  • 总页数 281
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 航空、航天技术的研究与探索;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号