Engineering Commons^™

Safety Assessment Of Road Vehicle In Crosswind Considering Driver Behavior, Jiexuan Hu

LSU Doctoral Dissertations

With expansion of the economy, more and more highway networks extend to coastal areas and mountain valley areas. Vehicles will be exposed to strong crosswinds when driven on these highway roads, especially in hurricane season and in winter in these two different topographic areas. Strong crosswinds threaten the safety of transportation infrastructure and passing vehicles in forms of vehicle accidents that usually result in traffic blockage and driver injury, posing negative effects on economic growth. This dissertation aimed to evaluate the vehicle safety when running through crosswinds in consideration of driver behaviors.

Firstly, the aerodynamic characteristics of road vehicles were …

Multiphase Cfd Modeling In Particle-Laden Flows, Zhizhong Ding

LSU Doctoral Dissertations

Multiphase modeling is prevalent and useful in solving problems involving multiphase interactions such as fluid and solid. Applications conclude but not limited to fluidized bed, hydraulic conveying, and many others. Modeling techniques with multiple scales can provide various states of details with diverse computational resources used. In this dissertation, two CFD multiphase models are used to disclose interaction details in the particulate system. Two-Fluid Model is used to solve pulsed fluidized bed problem and immersed boundary method based direct numerical method is used to solve particle’s behavior in shear flow. Getting a better understanding of these problems to help to …

Transient Flow Analysis Of A Closing Blowout Preventer Using Computational Fluid Dynamics (Cfd), Daniel Barreca

LSU Master's Theses

Reliability of blowout preventers (BOPs) is crucial for drilling and production operations. Erosion of BOP components and hydrodynamic forces on rams may cause failure of BOP elements to seal the well. Transient computational fluid dynamics (CFD) simulations of fluids within the wellbore and BOP offer quantitative and qualitative data related to this reliability during the closure of various BOP components. Since limited research has been published in transient CFD simulations of closing BOPs, this thesis discusses challenges and solutions to simulating closing blowout preventers. Single component fluids are simulated through several BOP geometries such as annular preventers, pipe rams, and …

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 …

Liquid Jet Penetration And Breakup In A Free Supersonic Gas Jet, Hansen Jones

LSU Master's Theses

In the testing of today’s rocket engines, both on large scale vertical test stands and smaller subscale horizontal component testing stands, it is extremely important to be able to accurately quantify and mitigate the thermal and acoustic loads the engines will generate on test stand infrastructure. Due to the large number of parameters that must be considered for many cases, development of a multi-phase computational code is under way to properly analyze and design water spray cooling systems used at NASA’s Stennis Space Center (SSC) and across other NASA centers. As such, a small-scale experiment has been conducted at Louisiana …

Multiphase Flow Modeling For Design And Optimization Of A Novel Down-Flow Bubble Column, Mutharasu Lalitha Chockalingam

LSU Doctoral Dissertations

The application of the Euler-Euler framework based Computational Fluid Dynamics (CFD) models for simulating the two-phase gas-liquid bubbly flow in down-flow bubble columns is discussed in detail. Emphasis is given towards the modelling and design optimization of a novel down-flow bubble column. The design features of this novel down-flow bubble column and its advantages over a conventional Plunging Jet down-flow bubble column are discussed briefly. Then, some of the present challenges in simulating a conventional Plunging Jet down-flow bubble column in the Euler-Euler framework is highlighted, and a sigmoid function based drag modification function is implemented to overcome those challenges. …

Applications Of Cfd Simulations On Chemical Processing Equipment Designs, Gongqiang He

LSU Doctoral Dissertations

The objective of this work is to achieve process intensification by seeking optimal equipment design with CFD investigations. In this work, two projects on chemical equipment design have been discussed.

The first project is on design and optimization of fractal distributor in a novel ion-exchanger. Flow distributors are adopted extensively by chemical industry to distribute an incoming process stream uniformly to the downstream equipment. Currently, the performance of chemical equipment installed with conventional distributor is severely undermined due to poor flow distribution. For conventional distributors such as spray nozzle distributors, their design concept is based on maintaining very high pressure …

Ambit Of Multiphase Cfd In Modelling Transport Processes Related To Oil Spill Scenario And Microfluidics, Abhijit Rao

LSU Doctoral Dissertations

During the ‘Deepwater Horizon’ accident in the deep sea in 2010, about 4.9 million barrels of oil was released into the Gulf of Mexico, making the spill one of the worst ocean spills in recent times. To mitigate the ill effects of the event on the environment, subsea injection of dispersants was carried out. Dispersant addition lowers the interfacial tension at oil/water interface and presence of local turbulence enhances the droplet disintegration process. The oil droplets contain a plethora of hydrocarbons which are soluble in water. In deep spill scenarios, droplets spend large amounts of time in water column; hence, …

Application Of Computational Fluid Dynamics To Near-Wellbore Modeling Of A Gas Well, Oscar Mauricio Molina

LSU Master's Theses

Well completion plays a key role in the economically viable production of hydrocarbons from a reservoir. Therefore, it is of high importance for the production engineer to have as many tools available that aid in the successful design of a proper completion scheme, depending on the type of formation rock, reservoir fluid properties and forecasting of production rates. Because well completion jobs are expensive, most of the completed wells are usually expected to produce as much hydrocarbon and as fast as possible, in order to shorten the time of return of the investment. This research study focused on the evaluation …

Applications Of Cfd Simulations On Fractal Fluid Distributor, Gongqiang He

LSU Master's Theses

Since its emergence in 1970s, process intensification has been attracting extensive research interests from both academic and industrial societies over the years. One good example of process intensification in chemical industry is the optimization of flow distributors. In many chemical processes, the uniformity of flow distributions plays the key role in determining the overall efficiency. Conventional distributors rely on high pressure drop to achieve acceptable flow distribution. With scaling symmetry from fractal, fractal distributors can handle fluid distribution much better than conventional distributors. With the rapid development of computation power and numerical simulation algorithms, Computer Fluid Dynamics (CFD) provides us …

Sedimentation Of Swarms Of Particles At Low And Moderate Reynolds Numbers, Oladapo Olanrewaju Ayeni

LSU Master's Theses

The sedimentation of a cloud of particles in a viscous fluid at low and moderate Reynolds numbers has been studied using an Eulerian-Lagrangian multiphase flow approach. We looked at the volume fraction dependence of the settling cloud and find a similar dependence in the simulations as in the theoretical predictions of (Nitsche and Batchelor 1997). The average cloud settling velocity and the velocity fluctuations around this average are found to have a functional dependence on ö^1/3 at negligible Reynolds number. The velocity fluctuations display strong anisotropy with the magnitude of the vertical component almost three times the magnitude of the …

Discrete Phase Simulations Of Drilled Cuttings Transport Process In Highly Deviated Wells, Doguhan Yilmaz

LSU Master's Theses

Transporting drilled cuttings from the bottomhole to the surface becomes more difficult and problematic in highly deviated wells than in vertical wells. Cuttings tend to settle down on the low side of the annulus typically in the form of a bed which can cause further problems. The height of this bed depends on many parameters such as annular domain geometry, drilling fluid density and rheology, annular flow rate, drill pipe rotation speed, cuttings size, shape, and their density. Prediction of the stationary cuttings bed height with respect to these aforementioned parameters is thus necessary to optimize the range of the …

Simulations Of The Primary Cement Placement In Annular Geometries During Well Completion Using Computational Fluid Dynamics (Cfd), Muhammad Zulqarnain

LSU Master's Theses

Effective zonal isolation during primary cementing is only possible when drilling mud in the annulus is completely displaced with cement, while the spacers aid in this process. During the displacement process the rheological properties of fluids used and the operating conditions control the motion of different fluids interfaces; desired stable interfacial displacement leads to piston like motion. Computational Fluid Dynamics (CFD) tool with the Volume-of-Fluid (VOF) has been validated against experimental and used to conduct numerical experiments in a virtual well model consisting of 50 ft vertical section of 8.765" x 12.5" annulus having initially mud and this mud is …

Applications Of Cfd Simulations On Microfluidic Systems For Nanoparticle Synthesis, Yuehao Li

LSU Master's Theses

Microfluidics has been extensively investigated as a unique platform to synthesize nanoparticles with desired properties, e.g., size and morphology. Compared to the conventional batch reactors, wet-chemical synthesis using continuous flow microfluidics provides better control over addition of reagents, heat and mass transfer, and reproducibility. Recently, millifluidics has emerged as an alternative since it offers similar control as microfluidics. With its dimensions scaled up to millimeter size, millifluidics saves fabrication efforts and potentially paves the way for industrial applications. Good designs and manipulations of microfluidic and millifluidic devices rely on solid understanding of fluid dynamics. Fluid flow plays an important role …

An Investigation Into Fuel Cells And Flow Cytometers Optimal Design, Etim Sunday Udoetok

LSU Doctoral Dissertations

The aim of the fuel cells part of this project was to investigate the performance of Proton Exchange Membrane Fuel Cells and closely related fuel cell types like the Alkaline Fuel Cells and Phosphoric Acid Fuel Cells. The investigation involved understanding the performance of fuel cells, addressing the shortcomings of currently used designs, and finding new methods for improving the performance of fuel cells. CFD was used to study flow channels and information learned from the study was used to design a new and improved flow channel. A prototype of the new design was fabricated, tested and found to perform …