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On The Fuel Spray Applications Of Multi-Phase Eulerian Cfd Techniques, Gabriel Lev Jacobsohn Oct 2019

On The Fuel Spray Applications Of Multi-Phase Eulerian Cfd Techniques, Gabriel Lev Jacobsohn

Masters Theses

Eulerian-Eulerian Computational Fluid Dynamics (CFD) techniques continue to show promise for characterizing the internal flow and near-field spray for various fuel injection systems. These regions are difficult to observe experimentally, and simulations of such regions are limited by computational expense or reliance on empiricism using other methods. The physics governing spray atomization are first introduced. Impinging jet sprays and Gasoline Direct Injection (GDI) are selected as applications, and modern computational/experimental approaches to their study are reviewed. Two in-house CFD solvers are described and subsequently applied in several case studies. Accurate prediction of the liquid distribution in a like-doublet impinging ...


Unsupervised-Learning Assisted Artificial Neural Network For Optimization, Varun Kote Jul 2019

Unsupervised-Learning Assisted Artificial Neural Network For Optimization, Varun Kote

Mechanical & Aerospace Engineering Theses & Dissertations

Innovations in computer technology made way for Computational Fluid Dynamics (CFD) into engineering, which supported the development of new designs by reducing the cost and time by lowering the dependency on experimentation. There is a further need to make the process of development more efficient. One such technology is Artificial Intelligence. In this thesis, we explore the application of Artificial Intelligence (AI) in CFD and how it can improve the process of development.

AI is used as a buzz word for the mechanism which can learn by itself and make the decision accordingly. Machine learning (ML) is a subset of ...


Numerical Investigation Of Coalescence-Induced Self-Propelled Behavior Of Droplets On Non-Wetting Surfaces And Wedged Surfaces., Yan Chen May 2019

Numerical Investigation Of Coalescence-Induced Self-Propelled Behavior Of Droplets On Non-Wetting Surfaces And Wedged Surfaces., Yan Chen

Electronic Theses and Dissertations

When small drops coalesce on a superhydrophobic surface, the merged drop can jump away from the surface due to the surface energy released during the coalescence. This self-propelled behavior has been observed on various superhydrophobic surfaces and has potential applications in areas related to the heat and mass transfer, such as heat exchangers, anti-icing and anti-frost devices, thermal management and water harvesting. The jumping velocity model was obtained based on published experimental data and the balance of various energy terms described in previous studies. However, the self-propelled mechanism is still not fully understood. In this study, the self-propelled droplet phenomenon ...


Cavitation Number As A Function Of Disk Cavitator Radius: A Numerical Analysis Of Natural Supercavitation, Reid Prichard Apr 2019

Cavitation Number As A Function Of Disk Cavitator Radius: A Numerical Analysis Of Natural Supercavitation, Reid Prichard

Senior Honors Theses

Due to the greater viscosity and density of water compared to air, the maximum speed of underwater travel is severely limited compared to other methods of transportation. However, a technology called supercavitation – which uses a disk-shaped cavitator to envelop a vehicle in a bubble of steam – promises to greatly decrease skin friction drag. While a large cavitator enables the occurrence of supercavitation at low velocities, it adds substantial unnecessary drag at higher speeds. Based on CFD results, a relationship between cavitator diameter and cavitation number is developed, and it is substituted into an existing equation relating drag coefficient to cavitation ...


Adding Semi-Structured Automated Grid Generation And The Menter-Shear Stress Turbulence Transport Model For Internal Combustion Engine Simulations To Novel Fem Lanl Combustion Codes, Brad Montgomery Philipbar Jan 2019

Adding Semi-Structured Automated Grid Generation And The Menter-Shear Stress Turbulence Transport Model For Internal Combustion Engine Simulations To Novel Fem Lanl Combustion Codes, Brad Montgomery Philipbar

Mechanical Engineering ETDs

The addition of GridPro semi-structured, automated generation of grids for complex moving boundaries for combustion engine applications and the Menter Shear Stress Turbulent Transfer (SST) model are being developed by Los Alamos National Laboratory. The software is called Fast, Easy, Accurate, and Robust Continuum Engineering (FEARCE). In addition to improving the time and effort required to build complex grid geometry for turbulent reactive multi-phase flow in internal combustion engines, the SST turbulence model has been programmed into the Predictor Corrector Fractional-Step (PCS) Finite Element Method (FEM) for reactive flow and turbulent incompressible flow regime validation is performed. The Reynolds-Averaged Navier-Stokes ...


Ignition And Extinction Behavior Of Fuels In A Microcombustor, Pawan Sharma Jan 2019

Ignition And Extinction Behavior Of Fuels In A Microcombustor, Pawan Sharma

LSU Doctoral Dissertations

Conventional fuel testing device-CFR engine requires large quantities of fuels, which makes it unsuitable for research of small samples of fuels. This current study seeks to address this limitation by using an externally heated microcombustor as an alternative fuel testing device. Mainly three combustion behaviors have been observed inside a microcombustor: strong flames at higher flow rates, Flames with Repetitive Extinction and Ignition (FREI) at intermediate flow rates, and weak flames at marginal flow rates. In previous studies, weak combustion behavior has been proven suitable to study fuel properties from small samples of fuels. Microcombustor experiments typically rely on flame ...


Using Cfd To Improve Off-Design Throughflow Analysis, Troy J. Lanchman Jan 2019

Using Cfd To Improve Off-Design Throughflow Analysis, Troy J. Lanchman

Browse all Theses and Dissertations

In turbomachinery design, complex internal flows give rise to significant losses and blockage whose effects are difficult to properly analyze without detailed computational fluid dynamics (CFD) methods or experiments. In a typical design method, CFD is used in conjunction with simpler throughflow or cascade codes to hasten the process. However, the lesser physical accuracy of the design codes demands the inclusion of models to improve the accuracy of the throughflow codes. This thesis aims to use CFD data to generate improved loss and blockage models for a 2D compressor throughflow code by matching throughflow data to CFD data using optimizations ...


Aerodynamics Of Fan Blade Blending, Clint J. Knape Jan 2019

Aerodynamics Of Fan Blade Blending, Clint J. Knape

Browse all Theses and Dissertations

Blending is a method of fan and compressor blade repair. The goal of the blending process is to remove stress concentration points such as cracks and nicks along the leading, trailing, or tip edges of the blade. The stressed areas are typically removed by grinding or cropping away the surrounding material. For integrally bladed rotor (IBR) disks, repairing a damaged blade is much more economical than replacing the entire disk. However, the change in shape of the blade will change the local aerodynamics and result in mistuning, both structurally and aerodynamically. In a worst case scenario, the change in the ...


Computational Study Of Water Desalination Using Forward Osmosis, Ahmed Mohammed Alshwairekh Jan 2019

Computational Study Of Water Desalination Using Forward Osmosis, Ahmed Mohammed Alshwairekh

Theses and Dissertations

Forward Osmosis is a natural phenomenon that takes places across a semi-permeable membrane when there is a concentration difference across the membrane. Pure water permeates to the highly concentrated channel until the concentration across the membrane equilibrates. In water desalination applications, the same principle is applied. Spiral-wound membrane, flat sheet, or hollow fiber module are typical configurations in forward osmosis desalination modules. The application of water desalination using forward osmosis requires the existence of two channels separated by a suitable forward osmosis membrane. Sea or Brackish water is introduced in one side while the other side has a suitable draw ...


Employing 2-D Cfd & Lrb Model Around Trees To Improve Vawt Placement, David Chukwuebuka Bassey Jan 2019

Employing 2-D Cfd & Lrb Model Around Trees To Improve Vawt Placement, David Chukwuebuka Bassey

All Theses, Dissertations, and Other Capstone Projects

In the placement of vertical axis wind turbines, trees are a constant presence in the vicinity. They are found to grow at different height and shape configurations. And in areas such as the Minnesota State University, Mankato (MNSU) campus, they serve as blockage to airflow; limiting the efficiency of installed turbines. This work sets the precedent for the validation of vegetative numerical models created for the Xcel Energy Research Development Fund (RDF) project.

Using two-dimensional (2-D) numerical simulations of porous cylinders placed in a rectangular medium of air, insight into the flow profile and distribution in the leeward side of ...


Numerical Simulation For The Hydrodynamic Performance Of Hydropower Turbine Near Free Surface, Zeda Yin Jan 2019

Numerical Simulation For The Hydrodynamic Performance Of Hydropower Turbine Near Free Surface, Zeda Yin

Theses, Dissertations and Capstones

The performance of hydropower turbine in shallow water can be affected by the presence of free surface. Therefore, it is of great interest to investigate the influence of free surface on hydropower turbine performance through computational simulations. For a better understanding of flow field around hydropower turbine operating in shallow water, it is important to analyze the flow over a single hydrofoil beneath free surface first. Therefore, as the first part of this thesis, the Computational Fluid Dynamics (CFD) methodology was used for numerical simulation of 2D unsteady incompressible viscous flow over a hydrofoil under the free surface. The computation ...


Mixing In Bi-Dispersed Granular Flows, Venkata Satya Pavan Kotrike Jan 2019

Mixing In Bi-Dispersed Granular Flows, Venkata Satya Pavan Kotrike

Graduate Theses and Dissertations

Autothermal pyrolysis is the process of converting biomass into biofuels and other chemical products where the energy for the pyrolysis process is obtained by partial oxidation of products. The sand acts as the fluidizing medium and heat carrier inside the fluidized bed reactor. Perfect mixing of biomass with sand particles enables better heat transfer, which further facilitates the devolatilization process to produce higher yields. The objective of this study is to use a multi-fluid Euler-Euler methodology to predict mixing and segregation phenomena in bi-dispersed flows. The method was extended to simulate the hydrodynamics of biomass and sand particles inside a ...


Computational Study Of Flow Interactions Over A Close Coupled Canard-Wing On Fighter, Setyawan Bekti Wibowo, Sutrisno Sutrisno, Tri Agung Rohmat Jan 2019

Computational Study Of Flow Interactions Over A Close Coupled Canard-Wing On Fighter, Setyawan Bekti Wibowo, Sutrisno Sutrisno, Tri Agung Rohmat

International Journal of Aviation, Aeronautics, and Aerospace

There have been many attempts to improve the flying performance of a fighter. By modifying the flow that occurs along the fuselage is expected to improve the performance of the aircraft. One of the indicators of combat aircraft performance is the ability to perform maneuver movement. Adding a canard as forewing on the fighter wing configuration is considered capable of raising the ability in maneuver movement. The use of canard-delta pairs will affect the performance and aerodynamic characteristics of the plane. Wings and canards with delta configuration will make the rolled-up vortex as a lifting force producer on the aircraft ...