Numerical simulation on syphonage effect of laval nozzle for low pressure cold spray system

2014 ◽  
Vol 214 (11) ◽  
pp. 2497-2504 ◽  
Author(s):  
Guosheng Huang ◽  
Daming Gu ◽  
Xiangbo Li ◽  
Lukuo Xing ◽  
Hongren Wang
2013 ◽  
Vol 2013.21 (0) ◽  
pp. _528-1_-_528-3_
Author(s):  
Keita KUDO ◽  
Takayuki KUWASHIMA ◽  
Yasuhiro YOSHINO ◽  
Tetsuya SONODA ◽  
Takashi SAITOH

Author(s):  
Richard D. Sandberg ◽  
Richard Pichler ◽  
Liwei Chen ◽  
Roderick Johnstone ◽  
Vittorio Michelassi

Modern low pressure turbines (LPT) feature high pressure ratios and moderate Mach and Reynolds numbers, increasing the possibility of laminar boundary-layer separation on the blades. Upstream disturbances including background turbulence and incoming wakes have a profound effect on the behavior of separation bubbles and the type/location of laminar-turbulent transition and therefore need to be considered in LPT design. URANS are often found inadequate to resolve the complex wake dynamics and impact of these environmental parameters on the boundary layers and may not drive the design to the best aerodynamic efficiency. LES can partly improve the accuracy, but has difficulties in predicting boundary layer transition and capturing the delay of laminar separation with varying inlet turbulence levels. Direct Numerical Simulation (DNS) is able to overcome these limitations but has to date been considered too computationally expensive. Here a novel compressible DNS code is presented and validated, promising to make DNS practical for LPT studies. Also, the sensitivity of wake loss coefficient with respect to freestream turbulence levels below 1% is discussed.


2012 ◽  
Vol 614-615 ◽  
pp. 77-82
Author(s):  
Jian Li ◽  
Li Zhang ◽  
Si Ping Wang

In order to obtain the more real condition of the flow field at condenser throat the flow field of condenser throat is numerical simulated by the FLUENT commercial software, alone or coupling with the low-pressure exhaust hood. The results show that the flow field of condenser throat is strongly influenced by low-pressure exhaust hood, the frustum’s diffuse-angle, the low-pressure heater and the injection of the exhaust steam from the small turbine. The velocity distribution at the outlet of the throat isn’t uniform. The calculation result of combined model is also different from the single calculation result of condenser throat. Combined numerical simulation obtains more reasonable result.


2012 ◽  
Vol 206 (16) ◽  
pp. 3488-3494 ◽  
Author(s):  
Seungchan Cho ◽  
Kenta Takagi ◽  
Hansang Kwon ◽  
Dowon Seo ◽  
Kazuhiro Ogawa ◽  
...  

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1044
Author(s):  
Marcin Winnicki

Based on the recent analysis of various databases, cold spray (CS), the newest method among thermal spraying technologies, has received the unabated attention of hundreds of researchers continuously since its invention in the 1980s. The significance of CS lies in the low process temperature, which usually ensures compressive residual stresses and allows for the formation of coatings on a thermally sensitive substrate. This paper concerns the low-pressure cold spray (LPCS) variant employed for forming metal matrix composites (MMCs) with high ceramic contents and all-ceramic coatings. At the very beginning, the influence of LPCS process parameters on deposition efficiency (DE) is analysed. In the next part, the most useful feedstock powder preparation techniques for LCPS are presented. Due to the combination of bottom-up powder production methods (e.g., sol-gel (SG)) with LCPS, the metal matrix that works as a binder for ceramic particles in MMC coatings can be removed, resulting in all-ceramic coatings. Furthermore, with optimization of spraying parameters, it is possible to predict and control phase transformation in the feedstock material. Further in the paper, differences in the bonding mechanism of metal–ceramic mixtures and ceramic particles are presented. The properties and applications of various MMC and ceramic coatings are also discussed. Finally, the exemplary direction of CS development is suggested.


Coatings ◽  
2017 ◽  
Vol 7 (7) ◽  
pp. 93 ◽  
Author(s):  
Guosheng Huang ◽  
Xiaodan Lou ◽  
Hongren Wang ◽  
Xiangbo Li ◽  
Lukuo Xing

2017 ◽  
pp. 95-142
Author(s):  
Roman Gr. Maev ◽  
Volf Leshchynsky
Keyword(s):  

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