Improving evaporative light scattering detector performance using experiments and modelling

需要更好地了解安捷伦的蒸发光散射检测器(ELSD)中的蒸发过程是如何工作的，以提高检测器的灵敏度。这一问题将通过开发物理和数值模型，更好地了解ELSD中的雾化和蒸发过程是如何工作的来解决，这将使探测器的灵敏度得到提高。该项目将涉及以下任务：1.开发关于雾化和蒸发过程、输入(几何形状和操作条件)和输出(液滴大小和探测器灵敏度，包括信号与总输入质量或浓度之间的关系)之间的实验的数据库。待研究的具体输入参数为：载气流量、温度和压力喷雾器几何参数：孔径大小、长度等。流动相特征：挥发性、粘度、密度等。待研究的特定输出参数为：颗粒特性(平均和尺寸分布、浓度)检测器灵敏度(散射信号，以及与原始质量的相关性)2.建立雾化、蒸发和散射的初步物理模型，包括：液滴分布与载流性质(载气速度、几何参数)、流体性质(粘度、密度)的函数关系的半经验模型，多组分流变学和蒸发的热力学模型，压力和温度(使用分子动力学模型和更简单的低阶模型)多分散粒子的散射模型对照观测结果测试初步模型以了解限制3。根据模型的性能，修改和考虑一维或三维模型以表示流动，或为热力学和散射模型提供更高的保真度。根据模型结果的比较，考虑ELSD的设计修改建议。

There is a need to get a better understanding of how the evaporation process works in Agilent's Evaporative Light Scattering detector (ELSD) to improve the sensitivity of the detector. This problem will be resolved by creating a better understanding of how the nebulisation and evaporation process works in the ELSD by developing physical and numerical models, which will allow the sensitivity of the detector to be improved. The following tasks will be involved in the project:1. Develop a database of experiments on the nebulisation and evaporation process, between inputs (geometry and operating conditions) and outputs (droplet sizes and detector sensitivity, including the relationship between signal and total input mass or concentration). Specific input parameters to be investigated are: Carrier gas flow rate, temperature and pressure Nebuliser geometric parameters: aperture size, length, etc. Mobile phase characteristics: volatility, viscosity, density etc.Specific output parameters to be investigated are: Particle characteristics (mean and size distribution, concentration)Detector sensitivity (scattering signal, and correlation with original mass)2. Develop a preliminary physical model for atomisation, evaporation and scattering, including: Semi-empirical models for droplet distribution as a function of carrier flow properties (carrier gas velocity, geometric parameters), fluid properties (viscosity, density) Thermodynamic models for multicomponent rheology and evaporation as a function of composition, pressure and temperature (using molecular dynamics models and simpler low order models) Scattering models for polydisperse particles Test preliminary model against observed results to understand limits3. Depending on the performance of the model, revise and consider 1D or 3D model to represent flow, or additional levels of fidelity for thermodynamic and scattering models.4. Based on comparison of model results, consider recommendations for design modification for ELSD.