• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Transverse jets and jet flames: Structure, scaling, and effects of the heat release.
【24h】

Transverse jets and jet flames: Structure, scaling, and effects of the heat release.

机译：横向射流和射流火焰：放热的结构，结垢和影响。

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

Many industrial combustion devices rely on turbulent jets in crossflow, also known as transverse jets, to achieve mixing and reaction. However, the literature affords limited predictive capability regarding the momentum and scalar mixing characteristics of the average flow. Detailed velocity data in the symmetry plane of the jet is relatively scarce, and the effect of heat release on burning jets has hardly been documented at all.; The first objective of the present work is to improve understanding of the transverse jet by deriving two sets of intermediate-asymptotic scaling laws, corresponding to jet-like behavior where the jet is only slightly deflected, and wake-like behavior where the jet is fully deflected. Scaling laws for velocity, scalar concentration, and jet trajectory show good agreement to data. The implied structure of the vorticity field represents a radical departure from classical concepts of the counter-rotating vortex pair.; The second objective is to measure and understand the details of the velocity field in the symmetry plane of the jet. Particle Image Velocimetry (PIV) measurements are made in the symmetry plane of cold and burning jets issuing into a wind tunnel at jet-to-crossflow blowing ratios of 10 and 20. Ensemble-averages and turbulence statistics of the velocity field are presented, and interesting features of the entrainment process in transverse jets are discussed.; Heat release affects the average flowfield markedly, with the most rapid change occurring near the base of the lifted flame. This observation motivates more detailed investigation into the dynamics of the flame base and instantaneous heat release/turbulence interactions throughout the flame. Simultaneous Planar Laser-Induced Fluorescence (PLIF) of the OH radical and PIV are employed to make direct observations of the flame/flow interaction. As the flow on the lee side passes through the flame base, for example, the average speed increases by a factor of 2–3; this effect is also observed over the flame as a whole, when compared with the non-reacting case. At the flame base, low flow speeds are often found in regions of high OH signal, implying that flame stabilization is partly governed by the availability of low-speed regions in the flowfield.
机译：许多工业燃烧设备依靠横流中的湍流射流（也称为横向射流）来实现混合和反应。但是，有关平均流量的动量和标量混合特性，文献提供的预测能力有限。射流对称面上的详细速度数据相对较少，几乎没有文献记录过放热对燃烧射流的影响。本工作的第一个目标是通过推导两组中间渐近定标定律来改善对横向射流的理解，这两个定律与射流仅略微偏转的射流状行为和射流完全偏转的尾流状行为相对应。偏转速度，标量浓度和射流轨迹的缩放定律与数据显示出很好的一致性。涡旋场的隐含结构代表了与反向旋转涡旋对的经典概念的根本偏离。第二个目标是测量和了解射流对称平面中速度场的细节。在以10与20的射流与横流吹气比吹入风洞的冷，热射流的对​​称平面中，进行粒子图像测速（PIV）测量，并给出了速度场的集合平均和湍流统计，并且讨论了横向射流中夹带过程的有趣特征。放热会显着影响平均流场，最迅速的变化发生在靠近火焰的底部。该观察促使对火焰基础的动力学以及整个火焰中的瞬时热量释放/湍流相互作用进行更详细的研究。 OH基和PIV的同时平面激光诱导荧光（PLIF）用于直接观察火焰/流动相互作用。例如，当背风侧的气流通过火焰底座时，平均速度增加了2-3倍；与不反应的情况相比，在整个火焰上也观察到这种效果。在火焰基部，通常在高OH信号区域发现低流速，这意味着火焰稳定部分取决于流场中低速区域的可用性。

著录项

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