AI 中文总结
研究开发基于激光诱导荧光的非侵入式光学诊断法测量盐溶液盐质量分数，利用双色比率法及荧光寿命测量技术，测试多种染料并与阴影图测量对比验证，分析不确定源，证明该方法对复杂多相流成像的扩展潜力，为传热传质定量诊断提供基础。
AI 中文摘要
本文开发了一种基于激光诱导荧光（LIF）的非侵入式光学诊断方法，用于测量与吸收式热泵应用相关的高浓度水溶液中的盐质量分数。该方法基于几种染料荧光发射光谱的系统性红移，这可能是由于盐质量分数增加导致离子强度增加所致。基于两个光谱带荧光强度比的双色比率法能够进行可靠的质量分数测量。研究表明该技术不仅限于溴化锂，对海水淡化应用中的氯化钠也适用。同时，利用时间相关单光子计数（TCSPC）进行的荧光寿命测量表明，荧光寿命也受溴化锂质量分数影响，提供了另一种测量技术。对两种技术都测试了多种染料并比较了盐质量分数灵敏度。通过与液滴蒸发过程中的阴影图测量对比，两种技术均得到独立验证。确定并分析了包括温度、再吸收效应和相变在内的关键不确定源。最后，初步结果证明了该方法向蒸发液滴平面成像及更复杂多相流扩展的潜力。该方法为未来解吸系统（如下降膜）中传热传质的定量诊断提供了基础。
英文摘要
A non-intrusive optical diagnostic based on Laser-Induced Fluorescence (LIF) is developed for measuring salt mass fraction in highly concentrated aqueous solutions relevant to absorption heat pump applications. The method relies on a systematic redshift of the fluorescence emission spectra of several dyes, likely induced by an increase of ionic strength with salt mass fraction. A two-color ratiometric approach, based on the ratio of fluorescence intensities in two spectral bands, enables robust mass fraction measurements. This study demonstrates that the techniques is not limited to LiBr but also NaCl, relevant for desalination applications. In parallel, fluorescence lifetime measurements using Time-Correlated Single Photon Counting (TCSPC) reveals that fluorescence lifetime is also affected by the LiBr mass fraction, allowing an alternative measurement technique. For both techniques, many dyes are tested and are compared in terms of salt mass fraction sensitivity. Both techniques are validated independently through comparison with shadowgraphbased measurements during evaporation of droplets. Good agreement is obtained in liquid-phase conditions over a wide range of salt mass fractions, confirming the reliability of the proposed diagnostics. Key sources of uncertainty including temperature, reabsorption effects and phase changes has been identified and analyzed. Finally, preliminary results demonstrate the potential extension of the approach toward planar imaging of evaporating droplets and more complex multiphase flows. The methodology provides a basis for future quantitative diagnostics of heat and mass transfer in desorption systems such as falling-films.
Journal ref22nd INTERNATIONAL SYMPOSIUM ON APPLICATIONS OF LASER AND IMAGING TECHNIQUES TO FLUID MECHANICS, Jun 2026, Lisbonne, Portugal
