Matching of Multiple Aerodynamic Parameters for Railway Train/tunnel Systems to Ensure Critical Airtightness Performance of High-Speed Trains

This study attempts to employ a multi-objective optimization algorithm and surrogate model technology to deal with the reasonable matching of key aerodynamic parameters of railway train/tunnel systems for train critical airtightness performance. All the calculation cases are obtained using the optimal Latin hypercube sampling method. The numerical method and its settings are verified through full-scale tests. The established relationship model of the main aerodynamic parameters for the amplitude of the pressure wave outside the train is accurate; however, it is relatively poor for the change rate of the pressure wave inside the train for 3 s. Pareto solutions are obtained from multi-objective optimization with the NSGA-III algorithm, from which two combinations of aerodynamic parameters are randomly selected to establish a simulation model for the numerical calculation. The calculated data are compared and analyzed with the predicted results of the previous two combinations selected from the Pareto solutions, which show that the differences in the maximum values of the amplitude of the pressure wave outside the train and the change rate of the pressure wave inside the train in a time of 3 s between the calculation and prediction are less than 7.5% and 25%, respectively. The method proposed in this paper can be used to predict the redundant space of multiple parameters for railway train/tunnel systems for the airtight performance of trains deteriorated after long-term operation; it can also be used to evaluate the adaptability of high-speed trains on transnational railway lines with different parameters. At present, this method has a few shortcomings in terms of accuracy; however, it can aid in simplifying the analysis and calculation in engineering pre-design and in considerably reducing project investments.