Passive Reduction of Leakage by Transverse Jet

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Filip Wasilczuk ◽  
Paweł Flaszyński ◽  
Piotr Kaczyński ◽  
Ryszard Szwaba ◽  
Piotr Doerffer ◽  
...  
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Mass Flow ◽  
Streamwise Vortices ◽  
Bypass Flow ◽  
Air Curtain ◽  
Flow Reduction ◽  
Transverse Jet ◽  
Experimental Researches ◽  
Good Agreement

Abstract This article presents investigations of mass flow reduction in a gap above a fin by the air curtain technique. The proposed method uses slots in the fin to generate a bypass flow and to create a fluidic barrier in the gap above the fin. Both numerical and experimental researches were conducted and the air curtain proved to be effective, showing the mass flow reduction up to about 20%. The comparison of numerical simulations and experimental data showed good agreement, and the flow structure details were analyzed based on the numerical results. The analysis shows that the blown air in the gap leads to creation of streamwise vortices. They enforce crosswise nonuniformity of the flow velocity in the gap and downstream, what finally influences on higher dissipation effects and mass flow reduction in the gap.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

Numerical Analysis of the Flow Inside a Centrifugal Compressor’s Vaneless Diffuser and Volute

2001 ◽  
Author(s):  
Hooman Rezaei ◽  
Abraham Engeda ◽  
Paul Haley
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Mass Flow ◽  
Operating Conditions ◽  
Vaneless Diffuser ◽  
Flow Angle ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Minimum Medium ◽  
Good Agreement

Abstract The objective of this work was to perform numerical analysis of the flow inside a modified single stage CVHF 1280 Trane centrifugal compressor’s vaneless diffuser and volute. Gambit was utilized to read the casing geometry and generating the vaneless diffuser. An unstructured mesh was generated for the path from vaneless diffuser inlet to conic diffuser outlet. At the same time a meanline analysis was performed corresponding to speeds and mass flow rates of the experimental data in order to obtain the absolute velocity and flow angle leaving the impeller for those operating conditions. These values and experimental data were used as inlet and outlet boundary conditions for the simulations. Simulations were performed in Fluent 5.0 for three speeds of 2000, 3000 and 3497 RPM and mass flow rates of minimum, medium and maximum. Results are in good agreement with the experimental ones and present the flow structures inside the vaneless diffuser and volute.

Determination of Minimum Fluidization Velocity for Gas-Solid Beds by Experimental Data and Numerical Simulations

2011 ◽  
Author(s):  
Meire Pereira de Souza Braun ◽  
Geraldo Luiz Palma ◽  
Helio Aparecido Navarro ◽  
Paulo Sergio Varoto
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Particle Diameter ◽  
Minimum Fluidization Velocity ◽  
Ergun Equation ◽  
Fluidization Velocity ◽  
Minimum Fluidization ◽  
Experimental Apparatus ◽  
Good Agreement

The purpose of this work is to predict the minimum fluidization velocity Umf in a gas-solid fluidized bed. The study was carried out with an experimental apparatus for sand particles with diameters between 310μm and 590μm, and density of 2,590kg/m3. The experimental results were compared with numerical simulations developed in MFIX (Multiphase Flow with Interphase eXchange) open source code [1], for three different sizes of particles: 310mum, 450μm and 590μm. A homogeneous mixture with the three kinds of particles was also studied. The influence of the particle diameter was presented and discussed. The Ergun equation was also used to describe the minimum fluidization velocity. The experimental data presented a good agreement with Ergun equation and numerical simulations.

Predicting Shrinkage in Semi-Crystalline Injection Mouldings – The Influence of Pressure

2006 ◽  
Vol 514-516 ◽  
pp. 1501-1505 ◽  
Author(s):  
A.J. Pontes ◽  
António Sergio Pouzada
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Pressure Data ◽  
Melt Viscosity ◽  
Effect Of Pressure ◽  
Experimental Pressure ◽  
Pressure Evolution ◽  
Good Agreement

In this study, the as-moulded shrinkage and pressure data are obtained experimentally and compared with numerical simulations. The mouldings were produced in polypropylene (PP). The effect of pressure on viscosity in the predicted pressure evolution was analyzed and also its influence on the shrinkage. The results show that the rise of holding pressure determines the reduction of the shrinkage. Also, it was observed that the pressure predictions are qualitatively in good agreement with the experimental data. However noticeable quantitative discrepancies can be observed when the effect of pressure on viscosity is not considered. If the effect of pressure on the melt viscosity is considered the deviation between predicted and the experimental pressure evolution is substantially reduced.

scholarly journals Comparison of Numerical Simulations of the Electron Density in the D-Region Ionosphere with Measurements of the Radar of Partial Reflections

2019 ◽  
Vol 224 ◽  
pp. 03011
Author(s):  
Aleksandr Gomonov ◽  
Roman Yurik ◽  
Yulia Shapovalova ◽  
Sergei Cherniakov ◽  
Olga Ogloblina
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Electron Density ◽  
High Electron ◽  
High Electron Density ◽  
Geophysical Institute ◽  
Partial Reflection ◽  
Polar Geophysical Institute ◽  
D Region ◽  
Good Agreement

The paper reports results of a comparison of the measured electron density in the ionospheric D-region measured using the partial reflection facility at the observatory. Tumanny of the Polar Geophysical Institute (69.0°N, 35.7°E) with numerical simulations performed using the theoretical model of the Polar Geophysical Institute (PGI) (Murmansk, Russian Federation). The model was examined using experimental data obtained under quiet geomagnetic conditions in March, 2017. The comparative analysis carried out in this study shows a very good agreement of the PGI model with experimental data and indicates that the IRI-2016 model fails to adequately reproduce measurements in regions with high electron density gradients.

Numerical Simulations of Hydraulic Jumps in Water Sloshing and Water Impacting

2001 ◽  
Vol 124 (1) ◽  
pp. 215-226 ◽  
Author(s):  
Tzung-hang Lee ◽  
Zhengquan Zhou ◽  
Yusong Cao
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Shallow Water ◽  
Numerical Investigation ◽  
Analytical Solutions ◽  
Water Reservoir ◽  
Hydraulic Jumps ◽  
Dam Breaking ◽  
Water Problems ◽  
Good Agreement

A numerical investigation on Glimm’s method as applied to water sloshing and impacting is carried out. Emphasis is given to the handling and predicting hydraulic jumps. The effects of the spatial and temporal discretizations are examined. Three shallow water problems, 1) dam-breaking problem, 2) water sloshing in a rolling tank, and 3) impact of breaking of a water reservoir, are studied. It is shown numerically that Glimm’s method is stable and converged solutions can be obtained. The characteristics of the hydraulic jumps are well captured by the numerical calculations. The numerical results are in good agreement with either analytical solutions or experimental data.

Experimental Validation of CFD Models Capturing the Thermal-Hydraulics in Liquid Metal Cooled Reactor Plena

2020 ◽  
Author(s):  
Brendan Ward ◽  
Thomas Hopkins ◽  
Hitesh Bindra
Keyword(s):  
Experimental Data ◽  
Liquid Metal ◽  
Numerical Simulations ◽  
Liquid Metals ◽  
Measurement Techniques ◽  
Quality Data ◽  
High Fidelity ◽  
Data Sets ◽  
Axial Distribution ◽  
Good Agreement

Abstract High fidelity velocity field experimental data in a liquid metal plenum is presented and compared with numerical simulations. While work has already been established for fluids like air and water, research on low Pr fluids (Pr ≪ 1) (e.g. liquid metals) has fewer experimental data sets with validation-quality data. Work in advanced reactors using liquid metal coolant requires validated numerical simulations for safety analyses. The Gallium Thermal-hydraulic Experiment (GaTE) facility is outfitted with acoustic backscattering measurement techniques to generate the high fidelity distributed flow field data in a liquid metal plenum (a 1/20th scale of the Department of Energy’s sodium cooled Advanced Burner Test Reactor design). The high spatial and temporal resolution of the sensors are required to capture the fluctuations of velocity to allow a more direct comparison to the numerical simulations. For these simulations the coupled mass and momentum equations under the large eddy simulation (LES) framework were solved with the wall-adapting local eddy-viscosity (WALE) model for sub-grid scale formulations. Since the temperature transients of interest for reactor safety have a period of about a minute in the GaTE system, there may not be enough time to allow statistical tools to check one-to-one correspondence. So the data collection period for both data sets was extended to allow convergence of the mean and a larger sample size for other statistics during system steady-state, isothermal tests. Two characteristic velocities of the plenum inlet barrel were investigated (U = 40, 60 mm/s; Re = 7,000, 11,000). Probability distributions show good agreement between experiment and simulation with the difference only in the low-probability tails that LES is not expected to simulate. The time averaged mean axial distribution of the vertical velocity also shows good agreement between the two setups.

Convective Oxygen Transport Enhancement in Intravenous Membrane Oxygenators

2003 ◽  
Author(s):  
Rodrigo A. Escobar ◽  
Cristina H. Amon
Keyword(s):  
Experimental Data ◽  
Computational Model ◽  
Numerical Simulations ◽  
Oxygen Transport ◽  
Transport Model ◽  
Moving Boundaries ◽  
Membrane Oxygenator ◽  
Transport Enhancement ◽  
Membrane Oxygenators ◽  
Good Agreement

Numerical simulations of blood and water flow and oxygen transport in a computational model of an intravenous membrane oxygenator including moving boundaries are presented. The simulations are compared to an analytical transport model which is validated by comparing its result to experimental data reported in the literature. Good agreement is found between numerical, analytical and experimental results.

scholarly journals Feasibility Study of Fluidic Sealing in Turbine Shroud

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3477
Author(s):  
Filip Wasilczuk ◽  
Pawel Flaszynski ◽  
Lukasz Pyclik ◽  
Krzysztof Marugi
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Parametric Study ◽  
Manufacturing Process ◽  
Turbine Blades ◽  
Control Technique ◽  
Leakage Flow ◽  
Streamwise Vortices ◽  
Air Curtain ◽  
Effective Dimensions

This paper analyses the methods for manufacturing turbine blades, focusing on the possibility of manufacturing slots in the region of the shroud. The reason for this analysis is the new flow control technique that can be used to limit the shroud leakage flow in a turbine—the air curtain. The air curtain uses a bypass slot to connect the upstream cavern of a shroud seal with the tip of a shroud fin. The bypass slot is an essential part of the solution, while at the same time introducing difficulties in the manufacturing process. Additionally, a parametric study on the bypass slot dimensions is performed using numerical simulations. The features of the numerical model and its validation against experimental data are presented. The parametric study includes the inlet and outlet dimensions, as well as the width of the slot. The most effective dimensions are shown, along with a possible explanation as to why they are the most effective. Interestingly, a slot that does not cover the whole span of the fin is more effective than a slot covering the whole span of the fin. This is caused by additional streamwise vortices that are created in the proximity of the bypass slot.

Experimental and Numerical Evaluation of the Bypass Flow in a Catalytic Plate Reactor for Hydrogen Production

2012 ◽  
Vol 9 (2) ◽  
Author(s):  
Haftor O. Sigurdsson ◽  
Søren K. Kær
Keyword(s):  
Experimental Data ◽  
Steam Reforming ◽  
Numerical Evaluation ◽  
Flow Resistance ◽  
Hydrogen Generation ◽  
Wire Mesh ◽  
Bypass Flow ◽  
Coated Wire ◽  
Flow Maldistribution ◽  
Good Agreement

Numerical and experimental study is performed to evaluate the reactant bypass flow in a catalytic plate reactor with a coated wire mesh catalyst for steam reforming of methane for hydrogen generation. Bypass of unconverted methane is evaluated under different wire mesh catalyst width to reactor duct width ratios, the results show that altering this ratio from 0.98 to 0.96 results in an increase in bypass mass flow of 22%. Effect of catalytic wire mesh flow resistance on bypass flow has also been investigated and results show increased bypass flow as catalytic wire mesh flow resistance increases. The numerical results are in good agreement with experimental data. The study improves the understanding of the underlying transport phenomena in these reactors and shows that the flow maldistribution in a catalytic plate reactor using a coated wire mesh has to be considered.

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