For a recent explosion risk assessment, a CFD (computational fluid dynamics)-based simulation has been widely employed using a 3D geometry model for a gas dispersion and an explosion simulation. For an accurate determination of explosion design loads, extensive scenarios covering various leak locations, leak directions, leak rate, wind directions and so on are treated in the simulation. In order to reflect the results of the risk assessment into detailed topside design, the time-consuming simulations should be begun from the early stage of the detailed design. However, the congestion level of 3D geometry modeling available at the early stage is considerably different from the as-built model due to the lack of modeling of small-sized piping, pipe supports, electrical supports, detailed structural outfitting and so on. This study proposes a method to generate 3D pipe modeling to compensate for the low congestion level. A random approach is made for the generation by randomly determining a starting point of a pipe spool, pipe diameter, pipe direction, a straight pipe length, number of pipes in a pipe spool and so on. For a pipe running through a given box range, it is cut out on the box boundary and a pipe type connecting with a neighboring module is also realized. For a longitudinally long pipe rack, the inside pipe spools have different features. The generation algorithm is adjusted to realize these features. The generated method doesn't include any algorithm to avoid existing other geometric entities such as equipment or structural members. Thus, the generated pipe length is generally reduced after combining with a module containing equipment and structural members. A study is also done about how much the pipe length of the as-built model needs to be increased considering the overlap. The proposed method is verified by combining the generated pipe model with a module containing only structure & equipment, and comparing explosion analysis results with the corresponding as-built model. A dispersion simulation is also performed for the validity of the proposed model in the dispersion simulation as well.

对于最近的爆炸风险评估，基于 CFD（计算流体动力学）的模拟已被广泛采用，使用 3D 几何模型进行气体扩散和爆炸模拟。为了准确确定爆炸设计载荷，模拟中处理了涵盖各种泄漏位置、泄漏方向、泄漏率、风向等的广泛场景。为了将风险评估的结果反映到详细的上部设计中，耗时的模拟应该从详细设计的早期阶段开始。然而，由于缺乏对小型管道、管道支架、电气支架、详细结构舾装等的建模，早期可用的3D几何建模的拥堵程度与竣工模型有很大不同。本研究提出了一种生成 3D 管道建模的方法，以补偿低拥堵水平。通过随机确定管段起点、管径、管向、直管段长度、管段内管数等进行随机生成。对于穿过给定箱体范围的管道，在箱体边界上进行切割，并实现与相邻模块连接的管道类型。对于纵向较长的管架，内管线轴具有不同的特性。调整生成算法以实现这些功能。生成的方法不包括任何算法来避免现有的其他几何实体，例如设备或结构构件。因此，与包含设备和结构构件的模块结合后，生成的管道长度通常会减少。还进行了一项关于考虑到重叠需要增加多少竣工模型的管道长度的研究。通过将生成的管道模型与仅包含结构和设备的模块相结合，并将爆炸分析结果与相应的竣工模型进行比较，验证了所提出的方法。还进行了色散模拟，以确保所提出的模型在色散模拟中的有效性。并将爆炸分析结果与相应的竣工模型进行比较。还进行了色散模拟，以确保所提出的模型在色散模拟中的有效性。并将爆炸分析结果与相应的竣工模型进行比较。还进行了色散模拟，以确保所提出的模型在色散模拟中的有效性。