In the Explosion Risk Analysis (ERA), ventilation and dispersion calculations using Computational Fluid Dynamics (CFD) are usually used when the level of confinement and congestion cannot be neglected. As far as the dispersion analysis is considered, alternative approaches are sought when a large number of simulations is required. Setting many scenarios and simulate them all is not always suitable within the time-frame of real engineering design. As a result, semi-empirical dispersion models and several procedures based on statistical approaches using CFD have been proposed by other researchers to improve the robustness and the accuracy of prediction of the flammable gas cloud volume. In addition, despite the use of Response Surface Method (RSM) and Frozen Cloud Approach (FCA), it is convenient to address the problem on the basis of the physics underlying the dispersion of a scalar in the chemical process area. In this work we developed a novel mathematical approach for dispersion calculations based on CFD data. We propose a new dimensionless number balancing the transport of the flammable cloud and the accidental leak rate. Numerical experiments have shown that the dimensionless number is related to the angle of the wind direction as the angles in a circle are related to the phase angle in a sine wave $\hat{V}\approx \text{sin}\left(k\frac{\phi }{\pi }+\beta \right),$ where $\hat{V}$ is the non-dimensional flammable cloud volume and φ the phase angle. The effect of wake wind is investigated and there seems to be no preferable wind direction that leads to the largest cloud volume in the module for the geometry considered in the current research.

在爆炸风险分析（ERA）中，当不能忽略约束和拥挤程度时，通常使用基于计算流体动力学（CFD）的通风和扩散计算。就色散分析而言，当需要大量仿真时，便寻求其他方法。在实际工程设计的时间范围内，设置许多方案并对其进行仿真并不总是合适的。结果，其他研究人员提出了基于经验方法的半经验弥散模型和若干程序，以提高鲁棒性和可燃气体体积预测的准确性。此外，尽管使用了响应面方法（RSM）和冻结云方法（FCA），根据标量在化学过程区域中的分散所基于的物理原理，方便地解决该问题。在这项工作中，我们为基于CFD数据的色散计算开发了一种新颖的数学方法。我们提出了一个新的无量纲数，以平衡可燃云的传输和意外泄漏率。数值实验表明，无量纲数与风向角有关，因为圆中的角与正弦波中的相角有关$\hat{V}\approx \text{罪}（ķ\frac{\phi }{\pi }+\beta ），$ 哪里 $\hat{V}$是无量纲可燃云体积，φ是相角。对尾流风的影响进行了调查，对于当前研究中考虑的几何形状，似乎没有最佳的风向导致模块中最大的云量。