Finlayson E U, Gadgil A J, Thatcher T L, Sextro R G
Indoor Environment Program, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
Indoor Air. 2004 Aug;14(4):272-83. doi: 10.1111/j.1600-0668.2004.00243.x.
This paper reports on an investigation of the adequacy of computational fluid dynamics (CFD), using a standard Reynolds Averaged Navier-Stokes (RANS) model, for predicting dispersion of neutrally buoyant gas in a large indoor space. We used CFD to predict pollutant (dye) concentration distribution in a water-filled scale model of an atrium with a continuous pollutant source in the absence of furniture and occupants. Predictions from the RANS formulation are comparable with an ensemble average of independent identical experiments. Model results were compared with pollutant concentration data in a horizontal plane from experiments in a scale model atrium. Predictions were made for steady-state (fully developed) and transient (developing) pollutant concentrations. Agreement between CFD predictions and ensemble averaged experimental measurements is quantified using the ratios of CFD-predicted and experimentally measured dye concentration at a large number of points in the measurement plane. Agreement is considered good if these ratios fall between 0.5 and 2.0 at all points in the plane. The standard k-epsilon two-equation turbulence model obtains this level of agreement and predicts pollutant arrival time to the measurement plane within a few seconds. These results suggest that this modeling approach is adequate for predicting isothermal pollutant transport in a large room with simple geometry.
CFD modeling of pollutant transport is becoming increasingly common but high quality comparisons between CFD and experiment remain rare. Our results provide such a comparison. We demonstrate that the standard k-epsilon model provides good predictions for both transient and fully developed pollutant concentrations for an isothermal large space where furnishings are unimportant. This model is less computationally intensive than a large eddy simulation or low Reynolds number k-epsilon model.
本文报告了一项关于使用标准雷诺平均纳维-斯托克斯（RANS）模型的计算流体动力学（CFD）预测大型室内空间中中性浮力气体扩散能力的研究。我们使用CFD预测了中庭充水比例模型中在无家具和人员情况下有连续污染物源时污染物（染料）浓度分布。RANS公式的预测结果与独立重复实验的总体平均值相当。将模型结果与比例模型中庭实验中水平面上的污染物浓度数据进行了比较。对稳态（充分发展）和瞬态（发展中）污染物浓度进行了预测。通过测量平面上大量点处CFD预测的染料浓度与实验测量的染料浓度之比来量化CFD预测与总体平均实验测量之间的一致性。如果这些比值在平面上所有点都落在0.5至2.0之间，则认为一致性良好。标准k-ε双方程湍流模型达到了这种一致性水平，并在几秒内预测了污染物到达测量平面的时间。这些结果表明，这种建模方法足以预测几何形状简单的大房间内的等温污染物传输。
污染物传输的CFD建模越来越普遍，但CFD与实验之间高质量的比较仍然很少。我们的结果提供了这样一种比较。我们证明，对于家具不重要的等温大空间，标准k-ε模型对瞬态和充分发展的污染物浓度都能提供良好的预测。该模型的计算强度低于大涡模拟或低雷诺数k-ε模型。
