A Numerical Study on the Effects of Apex Seal Leakage on Wankel Engine Flow Fields

1991 ◽  
Author(s):  
Z. Li ◽  
T. I-P. Shih ◽  
H. J. Schock ◽  
E. A. Willis
Author(s):  
Tong Li ◽  
Yibin Wang ◽  
Ning Zhao

The simple frigate shape (SFS) as defined by The Technical Co-operative Program (TTCP), is a simplified model of the frigate, which helps to investigate the basic flow fields of a frigate. In this paper, the flow fields of the different modified SFS models, consisting of a bluff body superstructure and the deck, were numerically studied. A parametric study was conducted by varying both the superstructure length L and width B to investigate the recirculation zone behind the hangar. The size and the position of the recirculation zones were compared between different models. The numerical simulation results show that the size and the location of the recirculation zone are significantly affected by the superstructure length and width. The results obtained by Reynolds-averaged Navier-Stokes method were also compared well with both the time averaged Improved Delayed Detached-Eddy Simulation results and the experimental data. In addition, by varying the model size and inflow velocity, various flow fields were numerically studied, which indicated that the changing of Reynolds number has tiny effect on the variation of the dimensionless size of the recirculation zone. The results in this study have certain reference value for the design of the frigate superstructure.


2017 ◽  
Vol 42 (38) ◽  
pp. 24319-24337 ◽  
Author(s):  
M. Ghasemi ◽  
A. Ramiar ◽  
A.A. Ranjbar ◽  
S.M. Rahgoshay

2019 ◽  
Vol 255 ◽  
pp. 113800 ◽  
Author(s):  
Cheng Shi ◽  
Changwei Ji ◽  
Yunshan Ge ◽  
Shuofeng Wang ◽  
Jianhui Bao ◽  
...  

Author(s):  
Hanzhang Yan ◽  
Wenxiang Quan ◽  
Jianrong Du ◽  
Huizi Li ◽  
Zhongmin Wan ◽  
...  
Keyword(s):  

2009 ◽  
Vol 29 (4) ◽  
pp. 732-739 ◽  
Author(s):  
Yuegui Zhou ◽  
Tongmo Xu ◽  
Shien Hui ◽  
Mingchuan Zhang

2011 ◽  
Vol 677 ◽  
pp. 483-502 ◽  
Author(s):  
C.-F. TAI ◽  
S. BIAN ◽  
D. HALPERN ◽  
Y. ZHENG ◽  
M. FILOCHE ◽  
...  

The liquid lining in small human airways can become unstable and form liquid plugs that close off the airways. Direct numerical simulations are carried out on an airway model to study this airway instability and the flow-induced stresses on the airway walls. The equations governing the fluid motion and the interfacial boundary conditions are solved using the finite-volume method coupled with the sharp interface method for the free surface. The dynamics of the closure process is simulated for a viscous Newtonian film with constant surface tension and a passive core gas phase. In addition, a special case is examined that considers the core dynamics so that comparisons can be made with the experiments of Bian et al. (J. Fluid Mech., vol. 647, 2010, p. 391). The computed flow fields and stress distributions are consistent with the experimental findings. Within the short time span of the closure process, there are large fluctuations in the wall shear stress. Furthermore, dramatic velocity changes in the film during closure indicate a steep normal stress gradient on the airway wall. The computational results show that the wall shear stress, normal stress and their gradients during closure can be high enough to injure airway epithelial cells.


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