CFD simulations of self-compacting concrete with discrete phase modeling

2018 ◽  
Vol 186 ◽  
pp. 20-30 ◽  
Author(s):  
Cenk Karakurt ◽  
Ahmet Ozan Çelik ◽  
Cem Yılmazer ◽  
Volkan Kiriççi ◽  
Ethem Özyaşar
Keyword(s):  
Self Compacting Concrete ◽  
Cfd Simulations ◽  
Discrete Phase Modeling ◽  
Discrete Phase

A Preliminary Study of the Blade Erosion for a Wind Turbine Operating in a Dusty Environment

2016 ◽  
Author(s):  
Ahmed Hossam El-Din ◽  
Aya Diab
Keyword(s):  
Leading Edge ◽  
Particle Collision ◽  
Turbine Engines ◽  
Surface Erosion ◽  
Coal Slurry ◽  
Predictive Tool ◽  
Ansys Fluent ◽  
Flow Parameters ◽  
Discrete Phase Modeling ◽  
Discrete Phase

The process of surface erosion due to particle collision has been the focus of a number of investigations with regards to gas turbine engines, aircraft, reentry missiles, pipelines carrying coal slurry, etc. Recently, increased interest in wind energy by countries in the Saharan regions of the Middle East and North Africa (MENA) brings about some concern about leading edge erosion of wind turbines operating under such dusty conditions. Leading edge erosion can have a detrimental impact on the extracted energy as it changes the blade surface roughness causing premature/unpredictable separation. Though erosion may not be easily avoided; it may be mitigated via using airfoil families characterized by low roughness sensitivity. In this paper, a model of an airfoil erosion subjected to sand blasting is developed using the discrete phase modeling capability in ANSYS-FLUENT along with the DNV erosion model. The effect of various flow parameters, such as angle of attack, and particle size, on the extent of erosion is investigated for a number of airfoil designs. The developed model is used as a predictive tool to assess the power deterioration of eroded wind blades.

Steady State Analysis of Heated Soil Vapor Extraction Process With Air Sparging

2005 ◽  
Author(s):  
P. M. Mohan Das ◽  
R. S. Amano ◽  
T. Roy ◽  
J. Jatkar
Keyword(s):  
Extraction Process ◽  
Soil Vapor Extraction ◽  
Air Sparging ◽  
Saturated Zone ◽  
Vapor Extraction ◽  
Combined System ◽  
Discrete Phase Modeling ◽  
Discrete Phase ◽  
Time Required ◽  
Heated Soil

Heated Soil Vapor Extraction (HSVE), developed by Advanced Remedial Technology is a Soil remediation process that has gained significant attention during the past few years. HSVE along with Air sparging has been found to be an effective way of remediating soil of various pollutants including solvents, fuels and Para-nuclear aromatics. The combined system consists of a heater/boiler that pumps and circulates hot oil through heating wells, a blower that helps to suck the contaminants out through the extraction well, and air sparging wells that extend down to the saturated region in the soil. Both the heating wells and extraction wells are installed vertically in the saturated region in contaminated soil and is welded at the bottom and capped at the top. The heat source heats the soil and the heat is transported inside the soil by means of conduction and convection. This heating of soil results in vaporization of the gases, which are then absorbed by the extraction well. Soil vapor extraction cannot remove contaminants in the saturated zone of the soil that lies below the water table. In that case air sparging may be used. In air sparging system, air is pumped into the saturated zone to help flush the contaminants up into the unsaturated zone where the contaminants are removed by SVE well. In this analysis an attempt has been made to predict the behavior of different chemicals in the unsaturated and saturated regions of the soil. This analysis uses the species transport and discrete phase modeling to predict the behavior of different chemicals when it is heated and absorbed by the extraction well. Such an analysis will be helpful in predicting the parameters like the distance between the heating and extraction wells, the temperature to be maintained at the heating well and the time required for removing the contaminants from the soil.

Transient Analysis of Heated Vapor Extraction System for Effective Remediation

2003 ◽  
Author(s):  
R. S. Jadhav ◽  
R. S. Amano ◽  
J. Jatkar ◽  
R. J. Lind
Keyword(s):  
Research Effort ◽  
Cost Effective ◽  
Extraction System ◽  
Vapor Extraction ◽  
Discrete Phase Modeling ◽  
Discrete Phase ◽  
Chemical Companies ◽  
Time Required ◽  
Volume Method ◽  
Remediation Process

A soil remediation process has gained an enormous attention for the last decade in order to make the surroundings environmentally friendly. The areas around chemical companies or waste disposal sites have been seriously contaminated from the chemicals and other polluting materials that are disposed off. Different soil remedial processes are used for different types of pollutants. The present research effort is concentrated on modeling the Heated Vapor Extraction System, which is a very efficient and cost effective process. A numerical model is developed and Finite Volume Method is used to solve the model. The analysis uses the species transport and discrete phase modeling to predict the time required to clean the soil under specific conditions. The analysis was used as a mathematical computational tool to predict various parameters for the process so that the process can be made more efficient and effective in remedial achievements.

Behavior of Micron-Sized Air Bubble in Operating FDBs by Using the Discrete Phase Modeling Method

2013 ◽  
Author(s):  
Y. H. Jung ◽  
G. H. Jang ◽  
K. M. Jung ◽  
C. H. Kang ◽  
H. H. Shin
Keyword(s):  
Fluid Dynamic ◽  
Disk Drive ◽  
Spindle Motor ◽  
Air Bubbles ◽  
Air Bubble ◽  
Discrete Phase Modeling ◽  
Discrete Phase ◽  
The Stability ◽  
Stiffness And Damping ◽  
Oil Injection

Fluid dynamic bearings (FDBs) have been applied to the spindle motor of a computer hard disk drive (HDD) because FDBs provide better dynamical characteristics of lower vibration and noise than ball bearings. However, one of the weaknesses of FBDs is the instability arising from the air bubble in oil lubricant of FDBs. Air bubbles are formed and trapped in oil lubricant by the inappropriate process of oil injection or the external shock. Trapped air bubbles decrease the rotational accuracy and the stability of a rotor-bearing system in such a way to generate non-repeatable run-out (NRRO) and to decrease the stiffness and damping coefficients of FDBs. It is important to predict the path of air bubbles in oil lubricant and to design FDBs in such a way to easily expel air bubbles out of operating FDBs.

scholarly journals Investigation by Discrete Phase Modeling Concerning Damage of Marine Piping due to Slurry Erosion

2009 ◽  
Vol 44 (6) ◽  
pp. 947-950
Author(s):  
Michiaki Ikai ◽  
Keiji Kishimoto ◽  
Tetsuo Hatanaka
Keyword(s):  
Slurry Erosion ◽  
Discrete Phase Modeling ◽  
Discrete Phase

scholarly journals Experimental validation of CFD simulations of bioaerosol movement in a mechanically ventilated airspace

2019 ◽  
pp. 5.01-5.14
Author(s):  
Amy La ◽  
Qiang Zhang
Keyword(s):  
Steady State ◽  
Mesh Size ◽  
Respiratory Syndrome Virus ◽  
Discrete Phase Model ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Mechanically Ventilated ◽  
Discrete Phase ◽  
Optimal Mesh ◽  
Ventilation Rates

A CFD (computational fluid dynamics) model was developed to simulate the movement of bioaerosols in mechanically-ventilated chambers and the results were validated with experiments. Liquid aerosols containing Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) were artificially generated in the chambers. Bioaerosol concentration was monitored with an optical particle counter until steady-state conditions were achieved (aerosols containing viruses are referred to as bioaerosols in this paper). Four treatments with two ventilation rates and two bioaerosol generation rates were tested. The standard k-ɛ turbulence model and a discrete phase model with unsteady tracking was used in an ANSYS Fluent CFD model to simulate the airflow and bioaerosol movement until steady-state was reached. A mesh refinement test was performed to select an optimal mesh size for simulations. The CFD simulations showed good agreement with the measured bioaerosol concentrations at steady-state with differences of 2% to 8%, normalized mean square error of 0.01 to 0.19, and fractional bias of 0.02 to 0.08. Simulations and validation during the transient phase could not be verified because of limited measurement locations.

scholarly journals Comparative Assessment of In Vitro and In Silico Methods for Aerodynamic Characterization of Powders for Inhalation

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1831
Author(s):  
Jelisaveta Ignjatović ◽  
Tijana Šušteršič ◽  
Aleksandar Bodić ◽  
Sandra Cvijić ◽  
Jelena Đuriš ◽  
...  
Keyword(s):  
In Silico ◽  
Aerodynamic Performance ◽  
Dry Powders ◽  
In Vitro Methods ◽  
Discrete Phase Modeling ◽  
Discrete Phase ◽  
Computational Fluid Dynamics Cfd ◽  
In Silico Methods

In vitro assessment of dry powders for inhalation (DPIs) aerodynamic performance is an inevitable test in DPI development. However, contemporary trends in drug development also implicate the use of in silico methods, e.g., computational fluid dynamics (CFD) coupled with discrete phase modeling (DPM). The aim of this study was to compare the designed CFD-DPM outcomes with the results of three in vitro methods for aerodynamic assessment of solid lipid microparticle DPIs. The model was able to simulate particle-to-wall sticking and estimate fractions of particles that stick or bounce off the inhaler’s wall; however, we observed notable differences between the in silico and in vitro results. The predicted emitted fractions (EFs) were comparable to the in vitro determined EFs, whereas the predicted fine particle fractions (FPFs) were generally lower than the corresponding in vitro values. In addition, CFD-DPM predicted higher mass median aerodynamic diameter (MMAD) in comparison to the in vitro values. The outcomes of different in vitro methods also diverged, implying that these methods are not interchangeable. Overall, our results support the utility of CFD-DPM in the DPI development, but highlight the need for additional improvements in these models to capture all the key processes influencing aerodynamic performance of specific DPIs.

Multiscale Modeling of Carbon Nanotube Bundle Agglomeration inside a Gas Phase Pyrolysis Reactor

MRS Advances ◽  
2017 ◽  
Vol 2 (48) ◽  
pp. 2621-2626 ◽  
Author(s):  
Guangfeng Hou ◽  
Vianessa Ng ◽  
Chenhao Xu ◽  
Lu Zhang ◽  
Guangqi Zhang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Gas Phase ◽  
Gas Flow ◽  
Flow Analysis ◽  
Multiscale Model ◽  
Discrete Phase Modeling ◽  
Discrete Phase ◽  
Computational Fluid Dynamics Cfd ◽  
Pyrolysis Reactor ◽  
Nanotube Bundle

ABSTRACTCarbon nanotube (CNT) sock formation is required for the continuous synthesis of CNT thread or sheet using the gas phase pyrolysis method. Nanometer diameter CNTs form and are carried along the reactor tube by gas flow. During the flow, the CNT stick to each other and form bundles of about 10-100 nm diameter. Coupling of the CNT bundles in the flow leads to the formation of a centimeter diameter CNT sock with a wall that is hundreds of nanometers thick. Understanding the multiscale phenomena of sock formation is vital for optimizing the CNT synthesis and manufacturing process. In this work, we present a multiscale model for the CNT bundle agglomeration inside a horizontal gas phase pyrolysis reactor. The interaction between CNT bundles was analyzed by representing the attraction forces between CNTs using a discrete phase modeling method. Flow in the synthesis reactor was studied using a computational fluid dynamics (CFD) technique with multiphase flow analysis. A model was proposed to represent the coupling between CNT bundles and the gas flow. The effect of different CNT bundles on the agglomeration phenomenon was analyzed. The modeling results were also compared with experimental observations.

Sign in / Sign up

Export Citation Format

Share Document