scholarly journals Numerical simulation of aerodynamics of a high-efficiency orthogonal balanced blade of a wind generator

2018 ◽  
Vol 251 ◽  
pp. 04063
Author(s):  
Valeriy Prokopiev ◽  
Irina Lantsova ◽  
Andrey Proskurin
Keyword(s):  
Numerical Simulation ◽  
Numerical Modeling ◽  
Turbulent Flow ◽  
High Efficiency ◽  
Two Dimensional ◽  
Wind Generator ◽  
Rotating Blade

The results of verification of numerical modeling of a rotating blade of a wind generator with a nonstationary turbulent flow around in a two-dimensional formulation are given. A design free from the drawbacks of a single-blade orthogonal high-efficiency turbine is considered (US Patent Victor Lyatkher, US 8007235 B1, August 30, 2011, RF Patent 2426911 C1).

scholarly journals Direct Numerical Simulation of a Spatially Advancing Turbulent Flow in a Two-Dimensional Curved Channel

2008 ◽  
Vol 74 (747) ◽  
pp. 2372-2379 ◽  
Author(s):  
Akihiko MATSUI ◽  
Koji MATSUBARA ◽  
Koji KAWAI ◽  
Takahiro MIURA ◽  
Hitoshi SUTO ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flow ◽  
Two Dimensional ◽  
Curved Channel

Numerical Simulation of Inter-Turbine Burner (ITB) Flows With the Inclusion of V-Gutter Flame Holders

2008 ◽  
Author(s):  
Cheng-Xian Lin ◽  
Balu Sekar ◽  
Joseph Zelina ◽  
Richard Jack Holder ◽  
Hugh Thornburg
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flow ◽  
Air Force ◽  
High Efficiency ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Flow Feature ◽  
Dissipation Model ◽  
Exit Temperature ◽  
Air Force Research Laboratory

In this paper, a three-dimensional numerical simulation has been performed to study the complex reactive flows during the combustion in an inter-turbine burner (ITB) with the inclusion of V-gutter flame holders. The ITB configuration, which has straight radial vanes (SRV), was based on the innovative, high efficiency, high-g Ultra-Compact Combustor (UCC) concept developed at the Air Force Research Laboratory (AFRL). The V-gutter’s angle of attack was varied from −10 to 10 degrees at fixed JET-A fuel and air injections. The turbulent flow in the ITB was modeled with a RANS-based realizable k-ε turbulence model, while the spray combustion is modeled with an eddy-dissipation model on an unstructured grid. Numerical results indicate that the V-gutter not only generates vortices behind itself, but also alters the turbulent flow feature and mixing behavior between main air flow and the circumferential and SRV cavity flows within the ITB. The exit temperature profile of the ITB can be modified substantially by the inclusion of the V-gutters at different angle of attack. The additional pressure drop incurred by the addition of the V-gutter was found to be less that 1%. Details of the vane cavity dynamics and increased entrainment physics are also discussed in the paper.

Speeded simulation of seismicity accompanying mining and hydrofracture

2018 ◽  
Vol 35 (5) ◽  
pp. 1932-1949
Author(s):  
Liliana Rybarska-Rusinek ◽  
Ewa Rejwer ◽  
Alexander Linkov
Keyword(s):  
Numerical Simulation ◽  
Numerical Modeling ◽  
Acoustic Emission ◽  
Real Time ◽  
Design Methodology ◽  
High Efficiency ◽  
Hierarchical Tree ◽  
Content Type ◽  
Large Group ◽  
Improved Methods

Purpose At present numerical simulation of seismicity, used in mining and hydraulic fracturing practice, is quite time expensive what hampers its combined employing with observed seismicity in real time. The purpose of this paper is to suggest a mean for drastic speeding up numerical modeling seismic and aseismic events. Design/methodology/approach The authors propose the means to radically decrease the time expense for the bottleneck stage of simulation: calculations of stresses, induced by a large group of already activated flaws (sources of events), at locations of flaws of another large group, which may be activated by the stresses. This is achieved by building a hierarchical tree and properly accounting for the sizes of activated flaws, excluding check of their influence on flaws, which are beyond strictly defined near-regions of strong interaction. Findings Comparative simulations of seismicity by conventional and improved methods demonstrate high efficiency of the means developed. When applied to practical mining and hydrofracturing problems, it requires some two orders less time to obtain practically the same output results as those of conventional methods. Originality/value The proposed improvement provides a means for simulation of seismicity in real time of mining steps and hydrofracture propagation. It can be also used in other applications involving seismic and aseismic events and acoustic emission.

scholarly journals NUMERICAL SIMULATION OF SLUMP FLOW TEST OF CEMENT PASTE COMPOSITES

2021 ◽  
Vol 30 ◽  
pp. 58-62
Author(s):  
Jiří Němeček ◽  
Jiří Němeček
Keyword(s):  
Numerical Simulation ◽  
Numerical Modeling ◽  
Laminar Flow ◽  
Boundary Conditions ◽  
Two Dimensional ◽  
Slump Flow ◽  
Vof Model ◽  
Flow Test ◽  
Model Set ◽  
Set Up

This study presents a numerical simulation of the mini-slump flow test performed on the Haegerman table, according to EN 1015-3. The two-dimensional axisymmetrical Volume of fluid (VOF) model is used for the calculation. Various scenarios with the different model set up and boundary conditions were calculated to show how the results are affected. Simulations with different lifting velocities were carried out and compared to the case with instantaneous demolding, which is commonly used in numerical simulations. Also, the effect on results is shown between noslip and specific shear boundary conditions on the mold. The results of simulations indicate that mold lifting should be considered in numerical modeling even if calculation time is highly prolonged. Lifting velocities should not exceed the value of 0.2 m/s in order to maintain laminar flow and stablecalculation.

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