An investigation of air inlet velocity in simulating the dispersion of indoor contaminants via computational fluid dynamics.
An investigation of air inlet velocity in simulating the dispersion of indoor contaminants via computational fluid dynamics.
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通过计算流体动力学模拟室内污染物扩散的进气速度研究。
DOI：
10.1093/annhyg/mef087
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Khan,Jamil
中科院分区：
文献类型：
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作者：
Lee,Eungyoung;Feigley,CharlesE;Khan,Jamil
计算流体动力学（CFD）是一个潜在的有价值的工具，模拟工作室中的空气污染物的扩散。然而，CFD估计的气流和污染物浓度模式并不总是表现出良好的协议与实验结果。因此，了解影响这种模拟的准确性的因素是其成功应用于职业卫生的关键。本研究的目的是验证CFD方法模拟气体和蒸汽在两个空气流速的封闭空间中的分散，并证明模拟精度的一个重要决定因素的影响。在1（L）× 0.3（H）× 0.7 m（W）的长方形小室中，用光电离分析仪在117个点上测定了示踪气体异丁烯的浓度。采用几何和运动学相似性准则对室内空气流速进行了缩放，以代表两个雷诺数（Re = 5 × 102和5 × 103）下的全尺寸房间。此外，还进行了CFD模拟，以估计整个灭菌室中的示踪气体浓度。对两种进气速度处理方法（在横穿进气口时测得的异形进气速度和假设进气口风速均匀）的模拟结果与实验结果进行了比较。CFD模拟的示踪气体浓度的三维分布，使用的轮廓入口速度表现出更好的协议定性和定量测量室浓度，而浓度估计使用均匀的入口速度显示出较差的协议，这两个比较。当可以确定入口速度时，对于估计室内空气污染物浓度，本研究表明，使用入口速度分布来定义CFD模拟的入口边界条件可以提供更可靠的估计。当入口速度分布未知时，例如对于稀释通风系统的预期设计，具有不同源、空气入口和空气出口位置的几种速度分布的试验对于确定最有效的工作室布局可能是有用的。
Computational fluid dynamics (CFD) is potentially a valuable tool for simulating the dispersion of air contaminants in workrooms. However, CFD-estimated airflow and contaminant concentration patterns have not always shown good agreement with experimental results. Thus, understanding the factors affecting the accuracy of such simulations is critical for their successful application in occupational hygiene. The purposes of this study were to validate CFD approaches for simulating the dispersion of gases and vapors in an enclosed space at two air flow rates and to demonstrate the impact of one important determinant of simulation accuracy. The concentration of a tracer gas, isobutylene, was measured at 117 points in a rectangular chamber [1 (L) × 0.3 (H) × 0.7 m (W)] using a photoionization analyzer. Chamber air flow rates were scaled using geometric and kinematic similarity criteria to represent a full-sized room at two Reynolds numbers (Re = 5 × 102and 5 × 103). Also, CFD simulations were conducted to estimate tracer gas concentrations throughout the chamber. The simulation results for two treatments of air inlet velocity (profiled inlet velocity measured in traverses across the air inlet and the assumption that air velocity is uniform across the inlet) were compared with experimental observations. The CFD-simulated 3-dimensional distribution of tracer gas concentration using the profiled inlet velocity showed better agreement qualitatively and quantitatively with measured chamber concentration, while the concentration estimated using the uniform inlet velocity showed poor agreement for both comparisons. For estimating room air contaminant concentrations when inlet velocities can be determined, this study suggests that using the inlet velocity distribution to define inlet boundary conditions for CFD simulations can provide more reliable estimates. When the inlet velocity distribution is not known, for instance for prospective design of dilution ventilation systems, the trials of several velocity profiles with different source, air inlet and air outlet locations may be useful for determining the most efficient workroom layout.