概括
一个新的10kHz拉曼仪器可以同时测量喷气中的物种密度和温度. 这种高速系统为气体流动动力学提供了详细的见解,即使在冷温度下也是如此.
科学领域:
- * 流体力学和气体动力学
- * 谱光诊断诊断技术使用
- * 基于激光的测量技术
背景情况:
- *对非反应性气体流的准确描述对于各种工业和科学应用至关重要.
- * 传统的测量技术往往缺乏对于短暂或复杂的流场所需的空间和时间分辨率.
- *同时测量多个流量特性,如温度和物种密度,具有挑战性,特别是在高速行驶时.
研究的目的:
- * 介绍一种新的10kHz,1-D拉曼仪器,用于同时测量物种数量密度和温度.
- * 为了证明仪器在非反应性,高度不扩张的 (H 2) 喷气中的能力.
- * 为了能够推导出额外的流量属性,如摩尔分数,绝对密度和压力.
主要方法:
- * 一个脉冲激光系统同步与四个CCD摄像机在爆破门模式.
- *获取四个关键的拉曼波段 (旋转式S (1) 和S (3);旋转式Q分支) 在10kHz.
- *双线比度温度计使用H 2旋转转变用于在广泛范围内的温度确定,包括冷条件.
主要成果:
- *成功的同时,高准确度获取物种数量密度和10kHz的温度场.
- * 证明了从环境到冷条件的温度测量.
- * 通过记录2毫秒短暂的H 2注入事件来展示时空分辨率能力,捕捉启动到衰变阶段.
结论:
- *开发的10kHz拉曼仪器为气流诊断提供了前所未有的时空分辨率.
- *同时测量密度和温度场,便于进行全面的流量表征.
- * 该仪器适用于分析各种气体组合中的短暂事件和复杂流体现象.
相关概念视频
01:26Raman Spectroscopy Instrumentation: Overview
532
A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector.
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
532
01:20Raman Spectroscopy: Overview
601
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of photons. When a monochromatic beam of light, typically from a laser source, interacts with a sample, most scattered light has the same frequency as the incident light. This is known as Rayleigh scattering.
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
601
01:27Atomic Spectroscopy: Effects of Temperature
460
Atomization, converting samples into gas-phase atoms and ions, is essential for atomic spectroscopy. The flame temperature required for atomization affects the efficiency of the atomic spectroscopic methods by increasing the atomization efficiency and the relative population of the excited and ground states.
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature...
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature...
460
01:25Atomic Absorption Spectroscopy: Atomization Methods
666
Atomic Absorption Spectroscopy (AAS) atomizes samples through flame atomization or electrothermal atomization. Flame atomization typically involves a nebulizer and spray chamber assembly to combine the sample with a fuel–oxidant mixture, creating a fine aerosol mist that enters a burner. Typically, the fuel and oxidant are combined in an approximately stoichiometric ratio. However, for atoms that are easily oxidized, a fuel-rich mixture may be more advantageous. Only about 5% of the...
666
01:22Atomic Absorption Spectroscopy: Instrumentation
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An atomic absorption spectrophotometer (AAS) comprises several components: a radiation source, an atomizer, a monochromator, and a detector. The radiation source can be a hollow-cathode lamp (HCL) or an electrodeless-discharge lamp (EDL), both of which provide a narrow emission line of the required wavelength. However, some instruments use continuum sources and high-resolution monochromators to achieve a narrow range of radiation.
The atomizer used in AAS can be either a flame atomizer or an...
The atomizer used in AAS can be either a flame atomizer or an...
963
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
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In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
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