Three-Dimensional Analysis of Generator Performance of Large-Scale DCW-MHD Generators with Circular and Square Cross-Section

2012 ◽  
Author(s):  
Naoyuki Niwa ◽  
Toru Takahashi ◽  
Takayasu Fujino ◽  
Motoo Ishikawa
Keyword(s):  
Dimensional Analysis ◽  
Cross Section ◽  
Large Scale ◽  
Three Dimensional ◽  
Generator Performance

Geometry Effects in Eulerian/Granular Simulation of a Turbulent FCC Riser with a (kg-?g)-KTGF Model

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Hamid Reza Nazif ◽  
Hassan Basirat Tabrizi ◽  
Farhad A Farhadpour
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Good Prediction ◽  
Model Predictions ◽  
Secondary Circulations ◽  
Sharp Corners ◽  
Granular Simulation

Three-dimensional, transient turbulent particulate flow in an FCC riser is modeled using an Eulerian/Granular approach. The turbulence in the gas phase is described by a modified realizable (kg-?g) closure model and the kinetic theory of granular flow (KTGF) is employed for the particulate phase. Separate simulations are conducted for a rectangular and a cylindrical riser with similar dimensions. The model predictions are validated against experimental data of Sommerfeld et al (2002) and also compared with the previously reported LES-KTGF simulations of Hansen et al (2003) for the rectangular riser. The (kg-?g)-KTGF model does not perform as well as the LES-KTGF model for the riser with a rectangular cross section. This is because, unlike the more elaborate LES-KTGF model, the simpler (kg-?g)-KTGF model cannot capture the large scale secondary circulations induced by anisotropic turbulence at the corners of the rectangular riser. In the cylindrical geometry, however, the (kg-?g)-KTGF model gives good prediction of the data and is a viable alternative to the more complex LES-KTGF model. This is not surprising as the circulations in the riser with a circular cross section are due to the curvature of the walls and not due to the presence of sharp corners.

Large Scale Topology Optimization of 3D Static Mixers

2020 ◽  
Author(s):  
Sicheng Sun ◽  
Jaal Ghandhi ◽  
Xiaoping Qian
Keyword(s):  
Topology Optimization ◽  
Pressure Drop ◽  
Cross Section ◽  
Large Scale ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Straight Channel ◽  
Navier Stokes Equation ◽  
Static Mixers ◽  
Static Fluid

Abstract Topology optimization (TO) was conducted for three dimensional static fluid mixers. The problem is optimized using the weakly coupled Navier-Stokes equation at low Reynolds number (Re ≤ 1) and a convection-diffusion equation. The domain was discretized with up to 10 million cells. The optimizations were run with 1024 to 2048 CPUs on a national supercomputer. For a mixer in a square cross-section channel, the mixing was improved by 83% for a modest 2.5 times higher pressure drop compared with the open straight channel. For a cylindrical cross-section tee arrangement, the mixing improved by 91% with a 2.5 times higher pressure drop compared to the straight channel.

scholarly journals STUDY ON NECESSITY OF LARGE-SCALE THREE-DIMENSIONAL ANALYSIS FOR EVALUATING SEISMIC RESPONSE OF LARGE TUNNEL HAVING COMPLEX STRUCTURE

2008 ◽  
Vol 64 (3) ◽  
pp. 639-652 ◽  
Author(s):  
Hiroshi DOBASHI ◽  
Tsuyoshi ICHIMURA ◽  
Naoto OHBO ◽  
Muneo HORI ◽  
Takemine YAMADA
Keyword(s):  
Seismic Response ◽  
Dimensional Analysis ◽  
Large Scale ◽  
Complex Structure ◽  
Three Dimensional ◽  
Large Tunnel

In situ investigation of the primary recrystallization of alpha titanium in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 634-635
Author(s):  
S. Naka ◽  
R. Penelle ◽  
R. Valle
Keyword(s):  
Dimensional Analysis ◽  
Texture Evolution ◽  
Cold Work ◽  
Three Dimensional ◽  
Primary Recrystallization ◽  
Thin Foils ◽  
In Situ Investigation ◽  
Grain Growth Model ◽  
Alpha Titanium

The in situ experimentation technique in HVEM seems to be particularly suitable to clarify the processes involved in recrystallization. The material under investigation was unidirectionally cold-rolled titanium of commercial purity. The problem was approached in two different ways. The three-dimensional analysis of textures was used to describe the texture evolution during the primary recrystallization. Observations of bulk-annealed specimens or thin foils annealed in the microscope were also made in order to provide information concerning the mechanisms involved in the formation of new grains. In contrast to the already published work on titanium, this investigation takes into consideration different values of the cold-work ratio, the temperature and the annealing time.Two different models are commonly used to explain the recrystallization textures i.e. the selective grain growth model (Beck) or the oriented nucleation model (Burgers). The three-dimensional analysis of both the rolling and recrystallization textures was performed to identify the mechanismsl involved in the recrystallization of titanium.

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