Numerical Study of Mold Filling Dynamics in “Cold-Box” Sand Coremaking Process

2001 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Numerical Simulations ◽  
Numerical Study ◽  
Mold Filling ◽  
Sand Core ◽  
Cold Box ◽  
Two Fluid ◽  
Core Shooting Process

Abstract In this paper we present the results of the numerical simulations of sand core shooting process using the CFD package FLOW-3D. The simulations are based on a two-fluid flow approach. The computation results are compared to experimental data obtained earlier.

Numerical Simulations and Experimental Study of Hot Core Distortion Phenomenon in Aluminum Casting

Volume 3 ◽  
2004 ◽  
Author(s):  
Sayavur Bakhtiyarov ◽  
Ruel A. Overfelt ◽  
Amit Suryawanshi ◽  
Johnathon Capps
Keyword(s):  
High Temperature ◽  
Numerical Simulations ◽  
Buoyancy Force ◽  
Metal Flow ◽  
Tensile Tests ◽  
Temperature Limit ◽  
Silica Sand ◽  
Sand Core ◽  
Aluminum Castings ◽  
Cold Box

This paper presents the results of experimental and numerical studies of hot distortion phenomenon in the phenolic urethane cold box systems. Dual Pushrod Dilatometer has been used to measure a thermal expansion/contraction of phenolic urethane cold box sand core specimens at temperature range from 25° C to 800° C. The high temperature tensile tests showed that the tensile strength of the phenolic urethane cold box silica sand cores is significantly affected by the bench life, temperature and binders level. High temperature hot distortion furnace tests on cylindrical cores showed that some aluminum coatings increase the temperature limit when distortion starts, but can’t prevent it. The hot distortion test aluminum castings showed that regardless of the application of coating, the type of coating, and anti-veining additives, all cores (silica sand) with density less than the density of the molten metal (aluminum alloy) were significantly distorted. Numerical simulations of the liquid metal flow around the cylindrical sand core and analysis of dynamic forces acting on the core during fill process showed that a buoyancy force is the major contributor to the hot distortion. It is concluded that the one of the solutions in preventing the hot distortion of sand cores is increasing their weigh, which will balance the buoyancy force and will bring the resultant force to the minimum. The hot distortion test castings using zircon sand cores (both coated and non-coated) with density almost equal to the density of the molten aluminum proved our predictions, and hot distortion has been prevented.

Numerical Simulations and Experimental Study of Liquid Metal Flow Around Sand Core

2005 ◽  
Vol 128 (3) ◽  
pp. 541-547
Author(s):  
Sayavur I. Bakhtiyarov
Keyword(s):  
High Temperature ◽  
Liquid Metal ◽  
Numerical Simulations ◽  
Buoyancy Force ◽  
Metal Flow ◽  
Tensile Tests ◽  
Metal Casting ◽  
Sand Core ◽  
Liquid Metal Flow ◽  
Cold Box

This paper presents the results of experimental and numerical studies of the hot distortion phenomenon in the phenolic urethane cold box systems used in metal casting. Dual Pushrod Dilatometry has been used to measure a thermal expansion/contraction of phenolic urethane cold box sand core specimens at temperatures ranging from 20°C to 600°C. High temperature tensile tests showed that the tensile strength of the phenolic urethane cold box sand cores is significantly affected by the bench life, temperature and binders level. High temperature hot distortion furnace tests on cylindrical cores showed that some coatings increase the temperature limit when distortion starts, but application of coating cannot prevent distortion. The hot distortion test during metal casting showed that regardless of the application of coating, the type of coating, and anti-veining additives, all cores with density greater than the density of the molten metal (magnesium alloy) were significantly distorted. Numerical simulations of the liquid metal flow around the cylindrical sand core and analysis of dynamic forces acting on the core during the fill process showed that a buoyancy force is the major contributor to the hot distortion. It is concluded that the one of the solutions in preventing the hot distortion of sand cores is optimizing their weight, which will balance the buoyancy force and will bring the resultant force to the minimum. The hot distortion test castings using optimized sand cores with density almost equal to the density of the molten magnesium proved our predictions, and hot distortion has been prevented.

Numerical study of fluid flow and power consumption in a stirred vessel with a Scaba 6SRGT impeller

2011 ◽  
Vol 32 (4) ◽  
pp. 351-366 ◽  
Author(s):  
Houari Ameur ◽  
Mohamed Bouzit ◽  
Mustapha Helmaoui
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Power Consumption ◽  
Yield Stress ◽  
Short Distance ◽  
Numerical Study ◽  
Stirred Vessel ◽  
Higher Power ◽  
Shear Thinning Fluid ◽  
Good Agreement

Numerical study of fluid flow and power consumption in a stirred vessel with a Scaba 6SRGT impeller The present work deals with agitation of non-Newtonian fluids in a stirred vessel by Scaba impellers. A commercial CFD package (CFX 12.0) was used to solve the 3D hydrodynamics and to characterise at every point flow patterns especially in the region swept by the impeller. A shear thinning fluid with yield stress was modelled. The influence of agitator speed, impeller location and blade size on the fluid flow and power consumption was investigated. The results obtained are compared with available experimental data and a good agreement is observed. It was found that an increase in blade size is beneficial to enlargement of the well stirred region, but that results in an increased power consumption. A short distance between the impeller and the tank walls limits the flow around the agitator and yields higher power consumption. Thus, the precise middle of the tank is the most appropriate position for this kind of impeller.

Laminar Fluid Flow in a Planar 90 Degree Bifurcation With and Without a Protruding Branching Duct

1996 ◽  
Vol 118 (1) ◽  
pp. 81-84 ◽  
Author(s):  
T. G. Travers ◽  
W. M. Worek
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Fluid Flow ◽  
Velocity Field ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Flow Field ◽  
Numerical Study ◽  
Main Duct

The laminar flow field in a planar, ninety degree bifurcation is examined. This numerical study uses the computational-fluid-dynamics software Fluent Version 4.11. First, the velocity field in a bifurcation without a protruding branching duct is modeled, and the results are successfully compared to experimental data. Next, the flow field is studied in bifurcations that have branching ducts that protrude into the main duct. The velocity field and pressure drop are documented, and are found to be strongly influenced by the extent of the branching duct protrusion.

Numerical Study on Hydraulic Performances of Pump as Turbine With Forward-Curved Blades

2014 ◽  
Author(s):  
Tao Wang ◽  
Fanyu Kong ◽  
Sunsheng Yang ◽  
Yanxia Fu
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Numerical Simulations ◽  
Turbulence Model ◽  
Numerical Study ◽  
Internal Flow ◽  
Hydraulic Turbine ◽  
Experimental Results ◽  
Computational Accuracy ◽  
Computational Stability

A reserved running centrifugal pump can work as a hydraulic turbine with its wide application in industrial energy recovery and the development of micro-hydraulic power. In order to improve the efficiency from the point of turbine working condition, the impeller with forward-curved blades was designed and the hydraulic performances were further analyzed based on the commercial software ANSYS CFX 12.0 in this study. Moreover, to improve the computational accuracy of numerical simulations on turbines, the grid number, the turbulence model, the circumferential flow distribution in the clearance between the volute and the impeller as well as the grid distribution in the boundary layer were considered. According grid independency analysis, the 1.2 million grids’ number was assumed for numerical simulations. Considering the consuming time and computational stability, as well as the accuracy of the CFD calculation, the k–ε turbulence model was chosen for further calculations. The shaft power and the efficiency of the turbine were more close to the experimental data as the whole computational flow domain in the clearance between the volute and the impeller was connected on the impeller domain. Compared with the performance curves with or without grids in the boundary layer, the boundary layer with grids used in the PAT during numerical simulations was more close to the experimental one. Compared with the experimental data, the H-Q curves of the hydraulic performances of the turbine with forward-curved blades predicted by CFD were positioned under the experimental one. With respect to the efficiency of the turbine, the various ranges of the efficiency is less than 5%, even there is some deviations between the CFD and experimental results. Therefore, the good agreement of the hydraulic performances between CFD and experimental results in present study indicates that the proposed numerical methods can adequately capture the internal flow in a hydraulic turbine with forward-curved blades, and can also provide a reliable reference for the design of hydraulic turbines.

scholarly journals Validation Strategy of Reduced-Order Two-Fluid Flow Models Based on a Hierarchy of Direct Numerical Simulations

2020 ◽  
Vol 105 (4) ◽  
pp. 1381-1411
Author(s):  
Pierre Cordesse ◽  
Alberto Remigi ◽  
Benjamin Duret ◽  
Angelo Murrone ◽  
Thibaut Ménard ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Numerical Simulations ◽  
Direct Numerical Simulations ◽  
Reduced Order ◽  
Flow Models ◽  
Two Fluid ◽  
Validation Strategy

Numerical study of the heat transfer of two fluid flow in partially heated enclosure

2011 ◽  
Vol 47 (7) ◽  
pp. 743-749
Author(s):  
Nader Ben-Cheikh ◽  
Nasreddine Ouertatani ◽  
Brahim Ben-Beya ◽  
Taieb Lili ◽  
Antonio Campo
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Study ◽  
Two Fluid

scholarly journals Numerical Study of Particle Interaction in Gas-Particle and Liquid-Particle Flows: Part I Analysis and Validation

2009 ◽  
Vol 1 (3) ◽  
pp. 217-244
Author(s):  
K. Mohanarangam ◽  
J. Y. Tu
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Numerical Study ◽  
Fluid Model ◽  
Particle Interaction ◽  
Sudden Expansion ◽  
Liquid Particle ◽  
Particle Flows ◽  
Dispersed Phases ◽  
Two Fluid Model

A detailed study into the turbulent behaviour of dilute particulate flow under the influence of two carrier phases namely gas and liquid has been carried out behind a sudden expansion geometry. The major endeavour of the study is to ascertain the response of the particles within the carrier (gas or liquid) phase. The main aim prompting the current study is the density difference between the carrier and the dispersed phases. While the ratio is quite high in terms of the dispersed phase for the gas-particle flows, the ratio is far more less in terms of the liquid-particle flows. Numerical simulations were carried out for both these classes of flows using an Eulerian two-fluid model with RNG based k- emodel as the turbulent closure. An additional kinetic energy equation to better represent the combined fluid-particle behaviour is also employed in the current set of simulations. In the first part of this two part series, experimental results of Fessler and Eaton (1995) for Gas-Particle (GP) flow and that of Founti and Klipfel (1998) for Liquid-Particle (LP) flow have been compared and analysed. This forms the basis of the current study which aims to look at the particulate behaviour under the influence of two carrier phases. Further numerical simulations were carried out to test whether the current numerical formulation can used to simulate these varied type of flows and the same were validated against the experimental data of both GP as well LP flow. Qualitative results have been obtained for both these classes of flows with their respective experimental data both at the mean as well as at the turbulence level for carrier as well as the dispersed phases.

Numerical Simulations of Fluid Flow During Electromagnetic Stirring of Metals

2001 ◽  
Author(s):  
Sorin G. Teodorescu ◽  
Mihai Dupac ◽  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Fluid Flow ◽  
External Magnetic Field ◽  
Numerical Simulations ◽  
Electric Conductivity ◽  
Electromagnetic Stirring ◽  
Metal Sample ◽  
Rotating Liquid ◽  
Better Than

Abstract In this paper we propose a new relationship between the opposing mechanical torque and the electric conductivity of a rotating liquid specimen in a permanent external magnetic field of constant induction. It is shown that the proposed relationship describes the experimental data for a rotating specimen better than Braunbeck formula derived under the assumption that a magnetic field rotates around a stationary metal sample.

Numerical Simulations of Cylinder VIV Focusing on High Harmonics

2009 ◽  
Author(s):  
Yiannis Constantinides ◽  
Owen H. Oakley
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
High Frequency ◽  
Hydrodynamic Force ◽  
Numerical Study ◽  
Flexible Cylinder ◽  
Cfd Simulations ◽  
High Harmonics ◽  
Qualitative Understanding ◽  
High Fatigue

The discovery of high frequency contributions in flexible cylinder VIV during the DeepStar experiments revealed a significant omission and raised concerns among riser designers due to the high fatigue contribution. Researchers are now focusing on this area by analyzing the sparse experimental data or performing simplified experiments. Building on past success with CFD simulations, this numerical study focuses on understanding the origin and cause of the 3rd harmonic in particular. An array of basic spring supported rigid cylinder and various configurations of flexible cylinder computations are performed to validate CFD and to gain a qualitative understanding. A relationship between the hydrodynamic force causing the 3rd harmonic and cylinder motion as well its spatial characteristics is established.

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