Experimental investigation of scalar dispersion in indoor spaces
Experimental investigation of scalar dispersion in indoor spaces
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DOI：
10.1016/j.buildenv.2024.111167
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发表时间：
2024-01
影响因子：
7.4
通讯作者：
H. D. Lim;T. Foat;S. Parker;C. Vanderwel
中科院分区：
文献类型：
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作者：
H. D. Lim;T. Foat;S. Parker;C. Vanderwel
利用粒子图像测速法和平面激光诱导荧光技术，在20:1和60:1的全模型房间模型中，对室内空间点源的标量色散进行了实验研究。通风入口主导着湍流的产生，观察到速度和雷诺应力的大小随着每小时换气量的增加而增加。平均浓度图显示了ACH和源位置的依赖性，这归因于近源区域的流场。峰均浓度对平均浓度和浓度方差图的依赖性较弱，表明如果仅基于这些信息，有毒化学品的风险可能被低估。浓度pdf通常用指数分布很好地描述，c99 / cr m s的值从不超过5.0。平流和湍流标量通量的大小强烈依赖于ACH和源位置，两者都不能以超过一个数量级的幅度支配对方。测量了涡旋扩散张量，并提出了一种基于条件平均的方法将其近似为各向同性涡旋扩散系数K。对于使用梯度输运模型使用K来估计湍流标量通量的实际应用，各向同性湍流的假设可能会引入17.8%左右的不确定性。
The scalar dispersion from point sources in indoor spaces is experimentally investigated using simultaneous particle–image velocimetry and planar laser-induced fluorescence techniques in a 20: 1 and a 60: 1 full-to-model scale room model. The ventilation inlets dominate turbulence production, with magnitudes of the velocities and Reynolds stresses observed to increase with air changes per hour (ACH). Mean concentration maps show a dependence on the ACH and source location which is attributed to the flow field at the near-source region. The peak-to-mean concentration shows a weak dependence on the mean concentration and concentration variance maps, indicating risk for toxic chemicals may be underpredicted if based only on these information. The concentration PDFs are generally well-described by exponential distributions with C 99/c r m s′ values never exceeding 5.0. The magnitudes of the advective and turbulent scalar fluxes are strongly dependent on the ACH and source location, neither of which are able to dominate the other by more than an order of magnitude. The eddy diffusivity tensor was measured and a conditional-averaging based method is proposed to approximate it to an isotropic eddy diffusion coefficient, K. For real applications where K is used to estimate magnitudes of the turbulent scalar flux using the gradient transport model, the assumption of isotropic turbulence can introduce an uncertainty of around 17.8%.