Pressure Fluctuation Analysis of the Defluidization Caused by a Reaction Involving Gas-Volume Reduction in a Fluidized Catalyst Bed

2015 ◽  
Vol 48 (6) ◽  
pp. 436-443 ◽  
Author(s):  
Takami Kai ◽  
Norihiro Tanaka ◽  
Kei Mizuta ◽  
Tsutomu Nakazato ◽  
Mitsuyuki Nakajima
2012 ◽  
Vol 38 (4) ◽  
pp. 272-277 ◽  
Author(s):  
Akihiro Matsumura ◽  
Takami Kai ◽  
Tsutomu Nakazato ◽  
Mitsuyuki Nakajima

Author(s):  
Qian-qian Li ◽  
Da-zhuan Wu

Due to the distinctive characteristic of massive flow rates, double-suction centrifugal pump has been extensively applied in lots of perspectives, such as drainage, irrigation, transportation projects and other hydraulic engineering realms. Nevertheless, the significance of the pressure fluctuation inside the double-suction centrifugal pump, which is getting more and more prominent under the soaring demands for low noise and comfortable living environment, could not be underestimated. Consequently, how to reduce the pressure fluctuation as far as possible and enhance the running stability of the pump is always the research hotspot. In this study, the double-suction centrifugal impeller with abominable vibration performance is redesigned to improve the internal flow and reduce the flow-induced noise. What’s addition, the two redesigned impellers wearing splitter blades were compared in staggered arrangement with different angles for the purpose of ulteriorly decreasing the pressure fluctuation. On the basis of Realizable k-ε model and SIMPLEC algorithm, the unsteady Reynolds-averaged Navier-Stokes equations (URANS) were resolved by means of CFD simulation and the flow performance and the vibration performance were validated with the experiments. The results illustrate that the redesigned impeller with multi-blade could raise the hydraulic performance and reduce the pressure fluctuation inside the pump. When the impeller of each side was laid with the staggered angle of 12 degrees, the pressure distribution tended to be more uniform and the pressure fluctuation was well ameliorated. Through the pressure fluctuation analysis in time domain and frequency domain, the pressure change inside the pumps could be evaluated quantitatively and accurately, hence different pumps could be contrasted in detail. The consequences of this paper could provide reference for pressure fluctuation reduction and vibration performance reinforcement of double-suction centrifugal pumps as well as other vane pumps.


2016 ◽  
Vol 284 ◽  
pp. 640-649 ◽  
Author(s):  
Jesús Gómez-Hernández ◽  
Daniel Serrano ◽  
Antonio Soria-Verdugo ◽  
Sergio Sánchez-Delgado

2020 ◽  
Vol 113 ◽  
pp. 56-65
Author(s):  
Ronaldo Correia de Brito ◽  
Mikel Tellabide ◽  
Idoia Estiati ◽  
José Teixeira Freire ◽  
Martin Olazar

Author(s):  
Yong Zhang ◽  
Baosheng Jin ◽  
Wenqi Zhong

Fluidization, mixing and segregation of a biomass-sand mixture in a 3D gas-fluidized bed have been investigated by means of visual observation, pressure fluctuation analysis and the bed-frozen method. Three types of mixtures are considered, in which biomass is a thin long stalk, and sand belongs to the Geldart B category. Experiments are carried out in a segmented fluidized bed equipped with multiple pressure transducers. Three initial packing conditions and two experiment procedures are used. The fluidization velocity varies to cover a wide range. Results show that in the local fluidization region, the mixing and segregation patterns are sensitive to the initial packing condition. In the case of a fully segregated state with biomass at the bottom, the bed inversion can be significantly observed due to the great segregation tendency of biomass. Further analyses indicate that the mixing ratio exerts a subtle influence on the competition between mixing and segregation by disturbing the coalescence and break-up of the bubble. In addition, the pressure fluctuation signal proves to be helpful in understanding the dynamic features of the phenomenology.


2009 ◽  
Vol 42 (10) ◽  
pp. 733-738 ◽  
Author(s):  
Takami Kai ◽  
Mitsunobu Furukawa ◽  
Kei-ich Toriyama ◽  
Tsutomu Nakazato ◽  
Mitsuyuki Nakajima

AIChE Journal ◽  
2010 ◽  
pp. NA-NA ◽  
Author(s):  
Takami Kai ◽  
Mitsunobu Furukawa ◽  
Tsutomu Nakazato ◽  
Toshio Tsutsui ◽  
Kei Mizuta ◽  
...  

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