scholarly journals Study of Snow Accumulation on a High-Speed Train’s Bogies Based on the Discrete Phase Model

2017 ◽  
Vol 10 (6) ◽  
pp. 1729-1745 ◽  
Author(s):  
F. Xie ◽  
Jie Zhang ◽  
G. Gao ◽  
K. He ◽  
Y. Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Snow Accumulation ◽  
Phase Model ◽  
Discrete Phase Model ◽  
Discrete Phase

A numerical study of snow accumulation on the bogies of high-speed trains based on coupling improved delayed detached eddy simulation and discrete phase model

2018 ◽  
Vol 233 (7) ◽  
pp. 715-730 ◽  
Author(s):  
Mingyang Liu ◽  
Jiabin Wang ◽  
Huifen Zhu ◽  
Sinisa Krajnovic ◽  
Guangjun Gao
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Snow Accumulation ◽  
Phase Model ◽  
Detached Eddy Simulation ◽  
Discrete Phase Model ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
Flow Mechanisms ◽  
Discrete Phase

A numerical simulation method based on the improved delayed detached eddy simulation coupled with a discrete phase model is used to study the influence of the snow on the performance of bogies of a high-speed train running in snowy weather. The snow particle trajectories, mass of snow packing on the bogie, and thickness of snow accumulation have been analyzed to investigate the flow mechanisms of snow accumulation on different parts of the bogies. The results show that the snow accumulation on the first bogie of the head vehicle is almost the same as that of the second bogie, but the total accumulated snow on the top side of the second bogie is more than 74% higher than that of the first bogie. Among all the components of the bogies, the motors were found to be strongly influenced by the snow accumulation. The underlying flow mechanisms responsible for the snow accumulations are discussed.

Numerical study on the anti-snow performance of deflectors in the bogie region of a high-speed train using the discrete phase model

2018 ◽  
Vol 233 (2) ◽  
pp. 141-159 ◽  
Author(s):  
Guangjun Gao ◽  
Yan Zhang ◽  
Fei Xie ◽  
Jie Zhang ◽  
Kan He ◽  
...  
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Snow Accumulation ◽  
Phase Model ◽  
High Speed Train ◽  
Discrete Phase Model ◽  
Discrete Phase ◽  
Deflector Plate

In this paper, the three-dimensional unsteady Reynolds-averaged Navier-Stokes equations with an RNG double-equation turbulence model and a discrete phase model were used for the investigation of snow accumulation on the bogie of a high-speed train. Two kinds of deflector plates, one installed at the front end and the other at the rear end of the bogie, were proposed to reduce snow accumulation. The accuracy of the CFD methodology was validated against wind tunnel tests. The results showed that high-speed air will impact the plates where snow particles get accumulated. The snow covering on the bogie rarely drifts back into the bogie region with air. The amount of accumulating snow in the optimum models is reduced by 50.58% on average as compared to those in the original models. At the rear end of the bogie, the inclined deflector plate reduced snow accumulation by up to 10.91% compared to the vertical deflector plate.

A numerical investigation on the improvement of anti-snow performance of the bogies of a high-speed train

2019 ◽  
Vol 234 (10) ◽  
pp. 1319-1334 ◽  
Author(s):  
Jiabin Wang ◽  
Yan Zhang ◽  
Jie Zhang ◽  
Xifeng Liang ◽  
Sinisa Krajnović ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
High Speed ◽  
Weather Conditions ◽  
Snow Accumulation ◽  
Navier Stokes ◽  
High Speed Train ◽  
Discrete Phase Model ◽  
Flow Features ◽  
High Speed Trains ◽  
Discrete Phase

In this paper, numerical simulations combining unsteady Reynolds-averaged Navier-Stokes (URANS) simulation and the discrete phase model are used to study the application of countermeasure for snow accumulation in the regions of bogie cavities of a high-speed train. The influence of the cowcatcher heights and guide structure configurations on the flow features and snow accumulation was studied. The results of the study show that the cowcatcher with a downward elongation of 4% of the distance between the two axles decreases the snow accumulation in the first and the second bogie regions by about 56.6% and 13.6%, respectively. Furthermore, the guide structures have been found to significantly alter the velocity and pressure distribution in the second bogie region, resulting in a relatively large snow-accumulation reduction. The deflector is found to perform better in reducing snow accumulation when compared to the diversion slots. The cowcatcher, elongated in the downward direction, and the deflector proved to be a good countermeasure for snow accumulation around the bogies of high-speed trains operating in snowy weather conditions.

Anti-snow performance of snow shields designed for brake calipers of a high-speed train

2018 ◽  
Vol 233 (2) ◽  
pp. 121-140 ◽  
Author(s):  
Jiabin Wang ◽  
Guangjun Gao ◽  
Yan Zhang ◽  
Kan He ◽  
Jie Zhang
Keyword(s):  
High Speed ◽  
Snow Accumulation ◽  
Cold Weather ◽  
High Speed Train ◽  
Detached Eddy Simulation ◽  
Discrete Phase Model ◽  
Railway Line ◽  
Eddy Simulation ◽  
Flow Features ◽  
Discrete Phase

When high-speed trains run on a snowy railway line in cold weather, a large amount of snow and ice will accumulate on the brake calipers, which can lead to huge safety problems. In this paper, to solve this issue, a numerical method based on the detached eddy simulation was used to explore the flow features of a high-speed train running in cold weather. The accuracy of mesh resolution and methodology of Computational Fluid Dynamics (CFD) was validated against the wind tunnel tests. A discrete phase model was used to investigate the process of snow accumulation on the brake calipers by analysing the movement characteristics of snow particles. Based on this analysis, three kinds of anti-snow packing shields for the brake calipers were designed, and the shielding effects were compared via numerical simulations. The results show that a large amount of snow particles below the bogie directly impact the brake calipers causing massive snow packing on the bottom surfaces; some snow particles reflected from the rear equipment cabin cover return to the bogie region and accumulates on the upper surfaces. With the application of anti-snow packing shields with trapezoidal-, triangular- and cambered-shaped openings, the rates of snow accumulation on the brake calipers were reduced by 18.53, 26.68 and 38.81%, respectively. The cambered type provides the best anti-snow packing performance for the brake calipers.

scholarly journals Enhanced discrete phase model for multiphase flow simulation of blood flow with high shear stress

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042110080
Author(s):  
Zheqin Yu ◽  
Jianping Tan ◽  
Shuai Wang
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Multiphase Flow ◽  
Experimental Verification ◽  
Flow Simulation ◽  
Turbulence Models ◽  
Phase Model ◽  
Force Model ◽  
Discrete Phase Model ◽  
Discrete Phase

Shear stress is often present in the blood flow within blood-contacting devices, which is the leading cause of hemolysis. However, the simulation method for blood flow with shear stress is still not perfect, especially the multiphase flow model and experimental verification. In this regard, this study proposes an enhanced discrete phase model for multiphase flow simulation of blood flow with shear stress. This simulation is based on the discrete phase model (DPM). According to the multiphase flow characteristics of blood, a virtual mass force model and a pressure gradient influence model are added to the calculation of cell particle motion. In the experimental verification, nozzle models were designed to simulate the flow with shear stress, varying the degree of shear stress through different nozzle sizes. The microscopic flow was measured by the Particle Image Velocimetry (PIV) experimental method. The comparison of the turbulence models and the verification of the simulation accuracy were carried out based on the experimental results. The result demonstrates that the simulation effect of the SST k- ω model is better than other standard turbulence models. Accuracy analysis proves that the simulation results are accurate and can capture the movement of cell-level particles in the flow with shear stress. The results of the research are conducive to obtaining accurate and comprehensive analysis results in the equipment development phase.

Effect of position of the fiber transport channel on fiber motion in the high-speed rotor

2021 ◽  
pp. 004051752110018
Author(s):  
Rui Hua Yang ◽  
Chuang He ◽  
Bo Pan ◽  
Hongxiu Zhong ◽  
Cundong Xu
Keyword(s):  
High Speed ◽  
Channel Model ◽  
Three Dimensional ◽  
Discrete Phase Model ◽  
Transport Channel ◽  
Rotor Spinning ◽  
Fiber Motion ◽  
Discrete Phase ◽  
Airflow Field ◽  
Fiber Transport

The task of the fiber transport channel (FTC) is to transport the fibers from the carding roller to the rotor. Its geometric position in the spinning machine has a strong influence on the characteristics of the airflow field and the trajectory of the fiber motion in both the rotor and the FTC. In this paper, a three-dimensional pumping rotor spinning channel model was established using ANSYS-ICEM-CFD software with three different positions of the FTC (positions a–c). Further, the simulations of air distribution were performed using Fluent software. In addition, the discrete phase model was used to fit the fiber motion trajectory in the rotor. The simulation results showed that among the three types of FTC, position b is the optimal condition. The gradients of airflow velocity in the channel at position b were greater than those of the other two positions, which is conducive to straightening of the fiber.

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