scholarly journals CFD analysis on a direct spring-loaded safety valve to determine flow forces

2021 ◽  
Author(s):  
Tamas Pusztai ◽  
Zoltan Simenfalvi
Keyword(s):  
Safety Valve ◽  
Measured Data ◽  
Cfd Analysis ◽  
Dynamics Model ◽  
Pressure System ◽  
Industrial Environment ◽  
Computational Fluid Dynamics Model ◽  
Simulated Flow ◽  
Good Agreement ◽  
Made In

AbstractSafety valves are the most important safety devices of the pressure system. For safety valves in the vast majority of cases in industrial environment, direct spring-loaded safety valves are used. The most important parameter of the equation of motion is the flow force. The main goal of the analysis was to compare the simulated flow forces with the measured results and validating the computational fluid dynamics model. Simulations were made in ANSYS 2019 R1 code for numerous fixed valve disk positions on different pressures. Results are in good agreement with the measured data.

Development of a simulator for ozone/UV reactor based on CFD analysis

2002 ◽  
Vol 46 (11-12) ◽  
pp. 13-19 ◽  
Author(s):  
M. Kamimura ◽  
S. Furukawa ◽  
J. Hirotsuji
Keyword(s):  
Fluid Dynamics ◽  
Hydrogen Peroxide ◽  
Radical Reaction ◽  
Reaction Model ◽  
Cfd Analysis ◽  
Dynamics Model ◽  
Uv Reactor ◽  
Completely Stirred Tank Reactor ◽  
Cstr System ◽  
Good Agreement

A new CFD (Computational Fluid Dynamics) simulator for an O3/UV reactor where ozone dissolved water flows under the irradiation of UV, has been developed by combining a fluid dynamics model with a complex radical reaction model. The radical reaction model used in this simulator was found to be reasonable, because the results obtained from the simulation of a completely stirred tank reactor (CSTR) system were in good agreement with the experimental results, e.g., the concentrations of total organic carbon (TOC), hydrogen peroxide and dissolved ozone obtained from a lab-scale CSTR. Furthermore, by using this CFD simulator, the distributions of substances such as hydroxyl radical (OHá) and hydrogen peroxide in the O3/UV reactor have been investigated. These distributions showed that this CFD simulator was considered to be reasonable. In addition, the simulation results suggested that conventional reactors were not optimized.

Thermal modelling and optimization of heat transfer in a high-temperature theatre luminaire

2003 ◽  
Vol 217 (9) ◽  
pp. 1039-1048 ◽  
Author(s):  
D E Anderson ◽  
T E Truslove ◽  
J Kubie
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Dynamics Model ◽  
Critical Temperatures ◽  
Computational Fluid Dynamics Model ◽  
Extended Surfaces ◽  
Theoretical Results ◽  
Modelling And Optimization ◽  
Good Agreement ◽  
Appreciable Reduction

A computational fluid dynamics model has been developed to predict the thermal performance of high-temperature theatre luminaires. The theoretical results are in good agreement with available experimental data. The model has been used to investigate the behaviour of the thermally sensitive areas of the luminaires. The model shows that an appreciable reduction of critical temperatures can be achieved by using extended surfaces at key locations. The model can also be used to evaluate and optimize future designs.

Multiphase Flow Modeling of Equiaxed Dendritic Solidification With Melt Convection

2002 ◽  
Author(s):  
Harald Laux ◽  
O̸yvind Nielsen
Keyword(s):  
Nucleation And Growth ◽  
Multiphase Model ◽  
Dendritic Solidification ◽  
Flow Modeling ◽  
Dynamics Model ◽  
Computational Fluid Dynamics Model ◽  
Multi Scale ◽  
Bed Height ◽  
Melt Convection ◽  
Good Agreement

A Computational Fluid Dynamics model for simulation of equiaxed dendritic solidification with melt convection and crystal transport is developed. This multi-scale multiphase model accounts for transport phenomena on the macro- and the microscales of a solidifying alloy. It predicts nucleation and growth of equiaxed dendrites from a melt, and their transport in the melt. Thermo-solutal convection and remelting of crystals are also included in the multiphase model that is based on the work of Wang and Beckermann (Metall. Mater. Trans. 27A, 1996, p. 2754). To verify the modeling results comparison to published experimental data were made (nucleation, growth and transport of equiaxed crystals from a cooled NH4Cl-70wt%H2O solution). It is shown that the predicted evolution of temperature and average bed height (due to crystal sedimentation) are in good agreement with the experimental results.

scholarly journals An approach to the modeling of a virtual thermal manikin

2014 ◽  
Vol 18 (4) ◽  
pp. 1413-1423 ◽  
Author(s):  
Dragan Ruzic ◽  
Sinisa Bikic
Keyword(s):  
Turbulence Models ◽  
Thermal Conditions ◽  
Heat Fluxes ◽  
Thermal Manikin ◽  
Flow Conditions ◽  
Body Segments ◽  
Nominal Size ◽  
Natural Flow ◽  
Good Agreement ◽  
Made In

The aim of the research described in this paper, is to make a virtual thermal manikin that would be simple, but also robust and reliable. The virtual thermal manikin was made in order to investigate thermal conditions inside vehicle cabins. The main parameters of the presented numerical model that were investigated in this paper are mesh characteristics and turbulence models. Heat fluxes on the manikin's body segments obtained from the simulations were compared with published results, from three different experiments done on physical thermal manikins. The presented virtual thermal manikin, meshed with surface elements of 0.035 m in nominal size (around 13,600 surface elements) and in conjunction with the two-layer RANS Realizable k-? turbulence model, had generally good agreement with experimental data in both forced and natural flow conditions.

Use of a three-dimensional model to predict heavy metal (copper) fluxes in the Oujiang estuary

2014 ◽  
Vol 69 (6) ◽  
pp. 1334-1343 ◽  
Author(s):  
Shasha Lu ◽  
Ruijie Li ◽  
Xiaoming Xia ◽  
Jun Zheng
Keyword(s):  
River Discharge ◽  
Water Surface ◽  
Three Dimensional ◽  
Measured Data ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Pollutant Concentrations ◽  
Suspended Sediment Concentrations ◽  
Adsorption Desorption ◽  
Good Agreement

Measuring pollutant concentrations in major tributaries is the standard method for establishing pollutant fluxes to the sea. However, this method is costly and difficult, and may be subject to a great deal of uncertainty due to the presence of unknown sources. This uncertainty presents challenges to managers and scientists in reducing contaminant discharges to water bodies. As one less costly method, a three-dimensional model was developed and used to predict pollutant fluxes to the sea. The sorptive contaminant model was incorporated into hydrodynamic and sediment models. Adsorption–desorption of copper by sediments in the Oujiang estuary were described using Henry's law. The model was validated using measured data for water surface elevations, flow velocity/direction, suspended sediment concentrations, and the proportion of copper sorbed to sediment. The validated model was then applied to predict fluxes of copper. Combined with the measured data, the copper concentration in the Oujiang River discharge was calculated as 13.0 μg/L and copper fluxes were calculated as 52 t in 2010. This copper flux prediction was verified using measured dissolved copper concentrations. Comparisons between the modeled and measured results showed good agreement at most stations, demonstrating that copper flux prediction in the Oujiang estuary was reasonably accurate.

Prediction of Defects in Multistage Cold Forging by Using Finite Element Method

2014 ◽  
Vol 622-623 ◽  
pp. 659-663 ◽  
Author(s):  
Fabio Bassan ◽  
Paolo Ferro ◽  
Franco Bonollo
Keyword(s):  
Radial Flow ◽  
Surface Defects ◽  
Plastic Instability ◽  
Cold Forging ◽  
Formation Mechanisms ◽  
Fe Model ◽  
Pipe Fitting ◽  
Tooling Design ◽  
Simulated Flow ◽  
Good Agreement

In this work, the formation mechanisms of surface defects in multistage cold forging of axisymmetrical parts have been studied through FEM simulations. As case history, the industrial production of an heating pipe fitting by cold forging has been analyzed. Based on simulated flow behaviour of material, several types of surface defects are identified and attributed to plastic instability of the work-material, inappropriate axial/radial flow ratio, excessive forming-pressure and uncorrect tooling design. The results of the FE model are finally compared with those obtained from real forging process and good agreement is observed.

scholarly journals Post-liquefaction reconsolidation of sand

2016 ◽  
Vol 472 (2186) ◽  
pp. 20150745 ◽  
Author(s):  
O. Adamidis ◽  
G. S. P. Madabhushi
Keyword(s):  
Void Ratio ◽  
One Dimensional ◽  
Geotechnical Centrifuge ◽  
Significant Damage ◽  
Pore Water Pressures ◽  
The One ◽  
Crucial Parameter ◽  
Excess Pore ◽  
Good Agreement ◽  
Made In

Loosely packed sand that is saturated with water can liquefy during an earthquake, potentially causing significant damage. Once the shaking is over, the excess pore water pressures that developed during the earthquake gradually dissipate, while the surface of the soil settles, in a process called post-liquefaction reconsolidation. When examining reconsolidation, the soil is typically divided in liquefied and solidified parts, which are modelled separately. The aim of this paper is to show that this fragmentation is not necessary. By assuming that the hydraulic conductivity and the one-dimensional stiffness of liquefied sand have real, positive values, the equation of consolidation can be numerically solved throughout a reconsolidating layer. Predictions made in this manner show good agreement with geotechnical centrifuge experiments. It is shown that the variation of one-dimensional stiffness with effective stress and void ratio is the most crucial parameter in accurately capturing reconsolidation.

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