{"title":"通过分子标记测量丙酮蒸气的扩散系数和动力学直径","authors":"Zongwei Zhang, Dominique Fratantonio, Christine Barrot Lattes, Marcos Rojas-Cardenas, Stéphane Colin","doi":"10.1007/s10404-024-02754-8","DOIUrl":null,"url":null,"abstract":"<div><p>The Molecular Tagging (MT) technique is a promising methodology for locally measuring velocity and temperature fields in rarefied gas flows. Recently, Molecular Tagging Velocimetry (MTV) has been successfully applied to gas flows in mini-channels in the continuum regime at high pressure and early slip-flow regime at lower pressure. As the operating pressure decreases, diffusion effects become more pronounced, and in MTV, they hinder the extraction of the correct velocity profile by simply dividing the displacement profile of the tagged molecular line by time of flight. To address this issue, a reconstruction method that considers Taylor dispersion was previously developed to extract the velocity profile, considering the diffusion effects of the tracer molecules within the carrier gas. This reconstruction method successfully extracted the correct velocity profile in the continuum flow regime. However, the method still faces challenges in the slip-flow regime. Since there is currently no consensus in the literature regarding the kinetic diameter value of acetone vapor, the diffusion coefficient estimation is uncertain especially at low pressures. This is why, in this study, we propose an original optical method to measure the diffusion coefficient of acetone vapor. This is achieved by linking the temporal evolution of the spatial photoluminescence distribution of acetone vapor to the diffusion coefficient via the Chapman-Enskog theory. Our research provides measurements of these parameters for a wide range of pressures (0.5–10 kPa) at ambient temperature.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":null,"pages":null},"PeriodicalIF":2.3000,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10404-024-02754-8.pdf","citationCount":"0","resultStr":"{\"title\":\"Measurements of diffusion coefficient and kinetic diameter of acetone vapor via molecular tagging\",\"authors\":\"Zongwei Zhang, Dominique Fratantonio, Christine Barrot Lattes, Marcos Rojas-Cardenas, Stéphane Colin\",\"doi\":\"10.1007/s10404-024-02754-8\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The Molecular Tagging (MT) technique is a promising methodology for locally measuring velocity and temperature fields in rarefied gas flows. 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Since there is currently no consensus in the literature regarding the kinetic diameter value of acetone vapor, the diffusion coefficient estimation is uncertain especially at low pressures. This is why, in this study, we propose an original optical method to measure the diffusion coefficient of acetone vapor. This is achieved by linking the temporal evolution of the spatial photoluminescence distribution of acetone vapor to the diffusion coefficient via the Chapman-Enskog theory. 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引用次数: 0
摘要
分子标记(MT)技术是局部测量稀薄气流中速度场和温度场的一种很有前途的方法。最近,分子标记测速仪(MTV)已成功应用于高压连续流和低压早期滑移流下的微型通道中的气体流动。随着工作压力的降低,扩散效应变得更加明显,在 MTV 中,它们阻碍了通过简单地将标记分子线的位移曲线除以飞行时间来提取正确的速度曲线。为了解决这个问题,之前开发了一种考虑泰勒色散的重构方法,以提取速度曲线,同时考虑示踪剂分子在载气中的扩散效应。这种重构方法成功地提取了连续流状态下的正确速度曲线。然而,该方法在滑移流动体系中仍面临挑战。由于目前文献中对丙酮蒸汽的动力学直径值还没有达成共识,因此扩散系数的估算并不确定,尤其是在低压条件下。因此,我们在本研究中提出了一种测量丙酮蒸汽扩散系数的原创光学方法。这是通过 Chapman-Enskog 理论将丙酮蒸气空间光致发光分布的时间演变与扩散系数联系起来实现的。我们的研究提供了在环境温度下对这些参数在广泛压力(0.5-10 千帕)范围内的测量结果。
Measurements of diffusion coefficient and kinetic diameter of acetone vapor via molecular tagging
The Molecular Tagging (MT) technique is a promising methodology for locally measuring velocity and temperature fields in rarefied gas flows. Recently, Molecular Tagging Velocimetry (MTV) has been successfully applied to gas flows in mini-channels in the continuum regime at high pressure and early slip-flow regime at lower pressure. As the operating pressure decreases, diffusion effects become more pronounced, and in MTV, they hinder the extraction of the correct velocity profile by simply dividing the displacement profile of the tagged molecular line by time of flight. To address this issue, a reconstruction method that considers Taylor dispersion was previously developed to extract the velocity profile, considering the diffusion effects of the tracer molecules within the carrier gas. This reconstruction method successfully extracted the correct velocity profile in the continuum flow regime. However, the method still faces challenges in the slip-flow regime. Since there is currently no consensus in the literature regarding the kinetic diameter value of acetone vapor, the diffusion coefficient estimation is uncertain especially at low pressures. This is why, in this study, we propose an original optical method to measure the diffusion coefficient of acetone vapor. This is achieved by linking the temporal evolution of the spatial photoluminescence distribution of acetone vapor to the diffusion coefficient via the Chapman-Enskog theory. Our research provides measurements of these parameters for a wide range of pressures (0.5–10 kPa) at ambient temperature.
期刊介绍:
Microfluidics and Nanofluidics is an international peer-reviewed journal that aims to publish papers in all aspects of microfluidics, nanofluidics and lab-on-a-chip science and technology. The objectives of the journal are to (1) provide an overview of the current state of the research and development in microfluidics, nanofluidics and lab-on-a-chip devices, (2) improve the fundamental understanding of microfluidic and nanofluidic phenomena, and (3) discuss applications of microfluidics, nanofluidics and lab-on-a-chip devices. Topics covered in this journal include:
1.000 Fundamental principles of micro- and nanoscale phenomena like,
flow, mass transport and reactions
3.000 Theoretical models and numerical simulation with experimental and/or analytical proof
4.000 Novel measurement & characterization technologies
5.000 Devices (actuators and sensors)
6.000 New unit-operations for dedicated microfluidic platforms
7.000 Lab-on-a-Chip applications
8.000 Microfabrication technologies and materials
Please note, Microfluidics and Nanofluidics does not publish manuscripts studying pure microscale heat transfer since there are many journals that cover this field of research (Journal of Heat Transfer, Journal of Heat and Mass Transfer, Journal of Heat and Fluid Flow, etc.).