Numerical Modeling of Aerosol Concentration

描述：本研究的长期目标是开发一个数字 用于预测气溶胶的浓度和尺寸分布的算法， 并评估将这种工具应用于职业健康的主要不确定性， 健康问题当前挑战的解决方案，例如人体建模 暴露于可吸入和可吸入颗粒物， 尺寸选择性气溶胶采样器，并优化通风设计 颗粒控制系统，由于缺乏全面的 数学建模方法对健康的影响，如慢性阻塞性 肺部疾病与材料和颗粒的毒性有关 颗粒尺寸选择性取样方法中所示的尺寸 ACGIH-化学物质的阈值限值中概述。 计算流体动力学（CFD）是一种很有前途的方法，这些和其他 问题，但目前还没有一个可行的方法来预测气溶胶 浓度场和尺寸分布。也有许多来源， 使用CFD模拟的不确定性，包括湍流模型 选择，施加的边界条件，以及现实的概念模型 输入计算机代码。本研究将：（1）提供一个 与计算流体动力学代码一起使用的工具，用于预测气溶胶浓度场和尺寸 分布，（2）开发和应用一种方法来评估 使用这一工具进行职业和 环境暴露问题。本建议与诺拉有关 研究重点：控制技术和个人防护设备， 暴露评估方法、干预效果和室内空气。在 此外，它是特别相关的，目前疾病预防控制中心的关注， 传染性病原体在城市中的传播（例如，生物恐怖主义），或 环境（例如，飞机）。具体目标是： 1)改进我们现有的计算机算法， 流体动力学软件，并作出预测的大小特定的气溶胶 浓度场 2)在大规模机器上开发并行实现以进行调查 算法的收敛性。 3)评估气溶胶预测中不确定性的重要来源 与职业健康问题有关的浓度。这些问题包括， (a)近尾流区的时间相关效应和湍流，（B） 数值收敛性和精度，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 改善劳动者教育。

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.