Numerical Modeling of Aerosol Concentration

描述：这项研究的长期目标是开发一种数值 预测气溶胶浓度和粒度分布的算法， 并评估将这一工具应用于职业的主要不确定性 健康问题。应对当前挑战的解决方案，如为人类建模 暴露在可吸入和可呼吸颗粒物中，评估 选择大小的气溶胶采样器和优化通风设计 颗粒物控制系统，由于缺乏全面的 数学建模方法。对健康的影响，如慢性梗阻 肺部疾病既与物质毒性有关，也与颗粒毒性有关 颗粒的尺寸选择取样方法中所示的尺寸 在ACGIH-化学物质的阈值限值中概述。 计算流体力学(CFD)是一种很有前途的方法 问题，但目前还没有一种可行的方法来预测气溶胶 浓度场和粒度分布。还有许多来源 CFD模拟使用中的不确定性，包括湍流模型 选择、施加的边界条件和现实的概念模型 输入到计算机代码中。本研究将：(1)提供免费的 与CFD代码一起使用以预测气溶胶浓度场和大小的工具 分配，以及(2)开发和应用评估方法 在使用此工具时存在的固有不确定性 环境暴露问题。这项建议与劳拉有关 研究重点：控制技术与个人防护装备， 暴露评估方法、干预效果和室内空气。在……里面 此外，它与疾控中心目前对 传染病在城市中的传播(例如，生物恐怖主义)，或封闭的 环境(例如，飞机)。具体目标是： 1)改进我们现有的计算机算法，以从计算中获取输出 流体动力学软件，并预测特定尺寸的气溶胶 浓度场。 2)在大型机器上开发并行实现以进行调查 算法的收敛速度。 3)评估气溶胶预报中的重要不确定源 与职业健康问题相关的浓度。这些问题包括： (A)近尾流区的随时间变化的效应和湍流，(B) 数值收敛和精度，以及(C)数值的可比性 预测和实验数据。 4)使用计算可视化工具来增强对 结果，提高职工教育水平。

DESCRIPTION: The long-term goal of this research is to develop a numerical algorithm for predicting the concentration and size distribution of aerosols, and to evaluate the major uncertainties in applying such a tool to occupational health problems. Solutions to current challenges such as modeling human exposure to inhalable and respirable particles, estimating the performance of size-selective aerosol samplers, and optimizing the design of ventilation systems for particulate control, are hindered by the lack of a comprehensive mathematical modeling methodology. Health effects such as chronic obstructive pulmonary disease are related to both the toxicity of the material and particle size as indicated in the size-selective sampling methodology for particles outlined in the ACGIH-Threshold Limit Value for Chemical Substances. Computational fluid dynamics (CFD) is a promising approach for these and other problems, but at present, there is not a viable method for predicting aerosol concentration fields and size distributions. There are also many sources of uncertainty in the use of CFD simulations, including the turbulence model selected, the boundary conditions imposed, and the conceptual model of reality input to the computer code. This research will: (1) provide a complimentary tool for use with CFD codes to predict aerosol concentration fields and size distributions, and (2) develop and apply a methodology to evaluate uncertainties inherent in the use of this tool for occupational and environmental exposure problems. This proposal has relevance to the NORA research priorities of: Control Technology and Personal Protective Equipment, Exposure Assessment Methods, Intervention Effectiveness, and Indoor Air. In addition it is particularly pertinent to current CDC concerns regarding the spread of infectious agents in urban (e.g., bio-terrorism), or enclosed environments (e.g., airplanes). The specific aims are to: 1) Improve our existing computer algorithm to take output from computational fluid dynamics software and make predictions of size-specific aerosol concentration fields. 2) Develop parallel implementations on large-scale machines to investigate convergence of the algorithm. 3) Assess important sources of uncertainty in the prediction of aerosol concentrations relevant to occupational health problems. These issues include, (a) time-dependent effects and turbulence in the near-wake region, (b) numerical convergence and accuracy, and (C) comparability of numerical predictions and experimental data. 4) Employ computational visualization tools to enhance interpretation of the results and to improve worker education.