Analysis of Design Variables of Aerodynamic Braking System for High-speed train

2018 ◽  
Vol 21 (2) ◽  
pp. 142-151
Author(s):  
Su-Hwan Yun ◽  
Min-ho Kwak
Author(s):  
Liang Zhang ◽  
Jiye Zhang ◽  
Tian Li ◽  
Yadong Zhang

In this work, a multiobjective aerodynamic optimization of a high-speed train head was performed to improve the aerodynamic performance of the high-speed train running on an embankment under crosswinds. Seven optimization design variables were selected to control five regions on the train head. The total aerodynamic drag force, aerodynamic lift force, and aerodynamic side force of the head coach were set as the optimization objectives. The optimal Latin hypercube sampling method was used to obtain the values of the design variables of the sample points. The high-speed train head was deformed using the free-form deformation approach through which the mesh morphing was performed without remodeling and re-meshing. Then, the aerodynamic performances of the high-speed trains at the sample points were calculated using the computational fluid dynamics method. A Kriging surrogate model between the design variables and their optimization objectives was constructed. Then, the multiobjective aerodynamic optimization of the high-speed train head was performed using multiobjective genetic algorithms based on the Kriging model. Based on the results of the sample points, the relationships between the optimization design variables and the optimization objectives were analyzed, and the contributions of the primary factors to the optimization objectives were obtained. After optimization, a series of Pareto-optimal head shapes were obtained. The steady and unsteady aerodynamic performances of the train with an optimal head, which was selected from the Pareto-optimal head shapes, were compared with those of the original train.


Author(s):  
Xiaojun Ma ◽  
Yuhua Qin ◽  
Dequan Kong ◽  
Desheng Liu ◽  
Chaoyang Wang

The high-speed trains are eight times more efficient than traditional trains because it significantly operates faster than the other trains; however, the train accidents are happened as because of its poor braking system. From this reason, effective braking system control techniques are developed. In this paper, the electric brake regenerative system is introduced to control the high-speed train. Therefore the braking system of a high-speed train is modeled in Brushless Direct Current (BLDC) motor, which is controlled by the gain of Proportional Resonant (PR) controller. Subsequently, the parameters of the controller and error percentage from the controller in the braking system are optimized using Multi-Objective African Buffalo Optimization (MOABO). The developed controller in braking system stability is analyzing by the Lyapunov function. The results of the braking system are validating by the torque and speed of the high-speed train braking system. Furthermore, the proposed high-speed braking system control is compared with existing control techniques in a high-speed train.


Author(s):  
Ruibin Wang ◽  
Jianjun Zhang ◽  
Shaojun Bian ◽  
Lihuan You

With the continuous increase of the running speed, the head shape of a high-speed train turns out to be the critical factor to boost the speed further. In order to reduce the time required to design the head of a high-speed train and to improve the modelling efficiency, various parametric modelling methods have been widely applied in the optimization design of the head of a high-speed train to obtain an optimal head shape so that the aerodynamic effect acting on the head of a high-speed train can be reduced and more energy can be saved. This paper reviews these parametric modelling methods and classifies them into four categories: two-dimensional, three-dimensional, CATIA-based, and mesh deformation-based parametric modelling methods. Each of the methods is introduced, and the advantages and disadvantages of these methods are identified. The simulation results are presented to demonstrate that the aerodynamic performance of the optimal models constructed by these parametric modelling methods has been improved when compared with the numerical calculation results of the original models or the prototype models of running trains. Since different parametric modelling methods used different original models and optimization methods, few publications could be found which compare the simulation results of the aerodynamic performance among different parametric modelling methods. In spite of this, these parametric modelling methods indicate that more local shape details will lead to more accurate simulation results, and fewer design variables will result in higher computational efficiency. Therefore, the ability of describing more local shape details with fewer design variables could serve as a main specification to assess the performance of various parametric modelling methods. The future research directions may concentrate on how to improve such ability.


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