An alternative algorithm of tunnel piston effect by replacing three-dimensional model with two-dimensional model

Publication date: 15 January 2018
Source:Building and Environment, Volume 128
Author(s): Minzhang Liu, Chunguang Zhu, Tong Cui, Huan Zhang, Wandong Zheng, Shijun You
With the rapid development of the underground railways in China, the subway has become an increasingly important mode of transportation. Owing to the significant influence piston wind has on tunnel ventilation, piston wind has gained much attention from researchers. At present, the most common method for this research is a three-dimensional Computational Fluid Dynamics (CFD) simulation. However, the three-dimensional model has its inherent characteristics. Large number of grid quantities, long calculation times, significant computational requirements and high technical personnel requirements all influence the development of the three-dimensional model applied into the practical engineering. This study aimed to simplify the complicated three-dimensional model by creating a simple two-dimensional dynamic mesh model while ensuring the accuracy of the simplified simulation results. In order to explore suitable alternative methods, six types of two-dimensional simulation models are suggested in this study. Firstly, in order to prove the accuracy of the dynamic mesh simulation method, the CFD simulation results were validated with experimental results. Secondly, the six alternative methods were applied to the experimental model, full-scale model, train passing through a tunnel model, and subway station model in order to determine the best two-dimensional method. Finally, grid number, calculation time, and internal storage usage between the two-dimensional simulations and the three-dimensional simulation were evaluated, and these results demonstrated the superiority of the two-dimensional simulation model.