scholarly journals Wind Tunnel Test Study for the Influence of Reynolds Number on the Aerodynamic Performance of High-speed Trains

Author(s):  
DAWEI CHEN ◽  
SHUANBAO YAO ◽  
PENG LIN ◽  
YUNDONG HAN
Author(s):  
Haitao Yang ◽  
Wei Xia ◽  
Kun Wang ◽  
Shuling Hu

The present work studies the aerodynamic performance of a small-scale rotor in tilting transition states through wind tunnel tests and numerical simulations. Firstly, the test platform for the rotor aerodynamics is built up, and the Computational Fluid Dynamics (CFD) model of flow field around the rotors is established based on the multiple reference frame method. Secondly, the effects of flow velocity, tilt angle and advance ratio on the aerodynamic performance of the rotor are investigated using both the numerical simulation and the wind tunnel test. It is found that for the Model 8038 rotor with maximum effeciency of 0.567 at advance ratio of 0.43, the rotor thrust coefficient increases with the increase of the Reynolds number. At Reynolds number of 410 thousand to 820 thousand, the thrust coefficient increases slightly with the increase of the rotating speed. The results also show that the thrust coefficient decreases with the increase of the advance ratio. With high-speed airflow and relatively low-speed rotation, “windmill” phenomenon is found in the experiment. The tilting of the rotor from level flight to hovering increases the thrust coefficient. Highly dependency of the tilt angle on the thrust coefficients at given advance ratios is found in the wind tunnel tests.


2021 ◽  
Author(s):  
Zhixiang Huang ◽  
Hanjie Huang ◽  
Weiping Zeng ◽  
Li Chen ◽  
Renyu Zhu

Abstract The influences of vestibule diaphragm gap, wheel-rail clearance, and strut-plate gap on the aerodynamic drag of a 1/8th-scale high-speed train model were investigated in an 8 m×6 m wind tunnel. The Reynolds number was set to 2.2×106 based on train height. It was found that the variation of the vestibule diaphragm gap changed the aerodynamic drag distribution pattern of each car; the drag coefficient of the head and middle cars might change as high as 45%; however, the change in the drag coefficient of the total train was very small. The effects of the strut-plate gap on the aerodynamic drag of each car and the total train were small. The effect of the wheel-rail clearance on the drag of the head car was not significant. It was suggested that the vestibule diaphragm gap, strut-plate gap and wheel-rail clearance of the 1:8 scale high-speed train model should not be greater than 11, 10, and 9 mm, respectively.


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