权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Development of Simultaneous and Instantaneous Measurement of Two-Dimensional Velocity Vectors and Scalar Profiles by Advanced Laser Image Diagnostics

通过先进激光图像诊断技术同时瞬时测量二维速度矢量和标量轮廓

基本信息

批准号：
08555056
负责人：
TAKAGI Toshimi
金额：
$ 10.5万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

The behavior of the flamelet is affected by the interaction between chemical reaction and turbulence and so it is useful to get instantaneous two-dimensional fluid velocity profiles together with the temperature and/or species concentration profiles to understand the characteristics of microscopic structure of the turbulent flames. In this study, by combining Rayleigh Scattering Image Velocimetry (RIV) with OH Laser Induced Fluorescence (OH-LIF), instantaneous and simultaneous measurements of two-dimensional temperature, OH concentration and velocity vectors profiles were made in a turbulent nitrogen-diluted hydrogen (H_2 30% + N_2 70%) diffusion flame. This measuring method enables us to estimate strain rate, temperature and OH concentration along the flame surface, which is obtained by tracing peak OH concentration, and to investigate local behavior of turbulent diffusion flames. OH concentration was measured quantitatively based on OH-LIF intensity and the calibration considering the OH-LIF quenching database. The strain rate along the flame surface (reaction zone of OH peak) was estimated by the velocity vectors and OH concentration profiles. The results obtained through this study are as follows. (1) Local temperature and OH concentration depression in the flame tends to occur when the flame inclines toward the centerline and the strain rate becomes positive and high. On the other hand, the flame that has locally high temperature and OH concentration tends no to have positive and high strain rate. (2) When the flame surface is pushed outward by the lateral convection motion, the radial position of OH concentration peak tends to be located prominently outside of the temperature peak. Their profiles are much different from those of the laminar flame. The considerably high OH concentration as compared with the laminar flame was observed where the flame does not have positive and high strain rate.

小火焰的行为受化学反应和湍流相互作用的影响，因此获得二维瞬时速度分布和温度和/或组分浓度分布有助于了解湍流火焰的微观结构特征。本文将瑞利散射图像测速技术(RIV)与氢气激光诱导荧光(OH-LIF)技术相结合，对湍流氮稀释氢(H_2 30%+N_2 70%)扩散火焰中的二维温度、氢气浓度和速度矢量分布进行了瞬时和同时测量。这种测量方法使我们能够估计沿火焰表面的应变率、温度和OH浓度，这是通过跟踪峰值OH浓度获得的，并能够研究湍流扩散火焰的局部行为。基于OH-LIF强度和考虑OH-LIF猝灭数据库的校准，定量测量了OH浓度。根据速度矢量和OH浓度分布估算了沿火焰表面(OH峰反应区)的应变率。通过本研究取得的成果如下。(1)当火焰向中心线倾斜，且应变率为正且较高时，火焰中的局部温度和OH浓度有下降的趋势。另一方面，局部温度和OH浓度较高的火焰往往具有正应变率和较高的应变率。(2)当火焰面被横向对流运动向外推进时，氢氧化氢浓度峰径向位置倾向于突出在温度峰外。它们的轮廓与层流火焰的轮廓有很大不同。与层流火焰相比，在火焰没有正应变率和高应变率的情况下，观察到相当高的OH浓度。