Coupled Flow Field Simulations Of Charring Ablators With Nonequilibrium Surface Chemistry,
2013
University of Michigan
Coupled Flow Field Simulations Of Charring Ablators With Nonequilibrium Surface Chemistry, Hicham Alkandry, Iain D. Boyd, Alexandre Martin
Mechanical Engineering Faculty Publications
This paper describes the coupling of a Navier-Stokes solver to a material response code to simulate nonequilibrium gas-surface interactions. The Navier-Stokes solver used in this study is LeMANS, which is a three-dimensional computational fluid dynamics code that can simulate hypersonic reacting flows including thermo-chemical nonequilibrium effects. The material response code employed in this study is MOPAR, which uses the one-dimensional control volume nite-element method to model heat conduction and pyrolysis gas behavior. This coupling is demonstrated using a test case based on the Stardust sample return capsule. Coupled simulations are performed at three different trajectory conditions. The effects of the …
Volume Averaged Modeling Of The Oxidation Of Porous Carbon Fiber Material,
2013
University of Kentucky
Volume Averaged Modeling Of The Oxidation Of Porous Carbon Fiber Material, Alexandre Martin
Mechanical Engineering Faculty Publications
Charring ablators remain the premium choice for space exploration missions that involve atmospheric re-entry. This type of ablative material is composed of a carbon matrix, usually made of fibers, which is then impregnated with a resin. During re-entry, the high heat flux produced by convective heating causes the material to chemically react. First, the resin pyrolyzes, and is vaporized into a gas that travels through the material, and is eventually ejected at the surface. Then, as the temperature rises, the surface of the porous matrix recess through ablative processes. For re-entry conditions typical of space exploration missions, this is mainly …
Flow-Tube Oxidation Experiments On The Carbon Preform Of Pica,
2013
University of Kentucky
Flow-Tube Oxidation Experiments On The Carbon Preform Of Pica, Francesco Panerai, Alexandre Martin, Nagi N. Mansour, Steven A. Sepka, Jean Lachaud
Mechanical Engineering Faculty Publications
Oxidation experiments on the carbon preform of a phenolic-impregnated carbon ablator were performed in the NASA Ames ow-tube reactor facility, at temperatures between 700 and 1300 K, under dry air gas at pressures between 103 and 104 Pa. Mass loss, volumetric recession and density changes were measured at different test conditions. An analysis of the diffusion/reaction competition within the porous material, based on the Thiele number, allowed us to identify low temperature and low pressure conditions to be dominated by in-depth volume oxidation. Experiments above 1000 K were found at transition conditions, where diffusion and reaction occur at similar scales. …
Multi-Dimensional Modeling Pyrolysis Gas Flow Inside Charring Ablators,
2013
University of Kentucky
Multi-Dimensional Modeling Pyrolysis Gas Flow Inside Charring Ablators, Haoyue Weng, Alexandre Martin
Mechanical Engineering Faculty Publications
Using an ablative thermal/material response code, the importance of three-dimensionality for modeling ablative test-article is addressed. In particular, the simulation of the pyrolysis gas flow inside a porous material is presented, using two different geometries. The effects of allowing the gas to flow out of the side wall are especially highlighted. Results show that the flow inside the test-article is complex, and that the 0D or 1D assumption made in most Material Response (MR) codes might not be valid for certain geometries.
Incorporating Aluminum Honeycomb To Increase Efficiency Of U-Tube Removable Heat Exchanger,
2013
California Polytechnic State University, San Luis Obispo
Incorporating Aluminum Honeycomb To Increase Efficiency Of U-Tube Removable Heat Exchanger, Daniel Soto, Daniel Corona
Aerospace Engineering
This report contains the results of attempting to improve on the results of Scott R. Sawyer and Alan M. L’Esperance research paper “Investigation of Paraffin Wax as an Energy Storage Medium Within a Shell-and-Tube Heat Exchanger.” The overall goal of the paper mentioned was to investigate the usefulness of wax as an energy storage medium. Scott R. Sawyer and Alan M. L’Esperance determined that “the amount of energy that can be released by the paraffin wax back to the airflow reaches a plateau, despite an increase in heating times.” They suggested that by surrounding the airflow tubes of a heat …
Global Skin Friction Diagnostics: The Glof Technique And Measurements Of Complex Separated Flows,
2013
Western Michigan University
Global Skin Friction Diagnostics: The Glof Technique And Measurements Of Complex Separated Flows, Sudesh A. Woodiga
Dissertations
This work describes the application of the global luminescent oil film skin friction meter to quantitative global skin friction diagnostics of complex separated flows. The development of this technique is based on the relationship between the oil film thickness and luminescent intensity of a luminescent oil film. The projected thin oil film equation is given to relate the normalized luminescent intensity with skin friction. The variational formulation with a smoothness constraint on skin friction is proposed to obtain a snap shot solution from two consecutive images for a relative skin friction field. A complete skin friction field is reconstructed through …
Supersonic Turbine Cascade Studies Using Computational Fluid Dynamics And Water Table Experiments,
2013
University of Nevada, Las Vegas
Supersonic Turbine Cascade Studies Using Computational Fluid Dynamics And Water Table Experiments, Shelby E. Nelson
Honors College Theses
Design engineers use a variety of tools to perform calculations and to aid in the design process. For example, engineers designing gas turbines, specifically the aerodynamicists, use a combination of hand calculations, experimental data, and complex numerical codes to simulate air flow around each blade. Aerodynamicists designing gas turbines must predict the locations of the shocks to locate inefficiencies in the flow. In this thesis, three methods of calculating the shock angles are compared: analytical, experimental, and computational. Three different airfoil shapes are tested: a rectangular flat plate, a supersonic diamond, and a turbine airfoil. Cascade tests of the airfoil …
Design Considerations And Requirements For In-Flight Refueling Of Unmanned Vehicles,
2013
Embry-Riddle Aeronautical University
Design Considerations And Requirements For In-Flight Refueling Of Unmanned Vehicles, Ian R. Mcandrew, Kenneth Witcher
Publications
The need to refuel in-flight has become a significant part of military strategy for air forces to work at further distances from safe shores. The use of Unmanned Vehicles is increasing and expected to be the principal part of military deployment. This paper will address the concepts and requirements for applying refueling unmanned vehicles in a military context for supporting fixed and rotor aircraft. Design aspects of human factors in the process are considered, reviewed and solutions proposed to allow for the first generation of designs to be developed. Furthermore, the practical and operational limitations will be addressed as part …
Broncoblade: An Open Source Wind Turbine Blade Analysis Tool,
2013
Western Michigan University
Broncoblade: An Open Source Wind Turbine Blade Analysis Tool, Alex R. Quinlan
Masters Theses
This thesis reports the development and validation of BroncoBlade, a horizontal axis wind turbine analysis tool. BroncoBlade prepares finite element models and integrates them with an aeroelastic simulator. Analysis results for the SNL100-00 baseline blade are evaluated against reference results published by Sandia National Laboratories. Variations on the SNL100-00 blade incorporating carbon fiber are compared to the baseline blade.
Development Of Cfd Models For The Purposes Of Exploring Free Surface Wave Phenomena,
2013
Western Michigan University
Development Of Cfd Models For The Purposes Of Exploring Free Surface Wave Phenomena, Leonard P. Stoehr
Masters Theses
With the push for finding alternative, green energy sources, the harnessing of energy from ocean and lake waves is becoming a more researched field. To fully understand the behavior of wave interactions and optimize designs to extract this energy, it is necessary to develop computer models that can accurately replicate this behavior. A case is presented in which previous work done using the wave tank found in the Western Michigan University fluids lab is examined. The case involves harnessing the energy generated by ocean waves through the usage of plates of different shapes resting horizontally on the water’s surface. The …
Investigation Of Pulse Detonation Engines; Theory, Design And Analysis,
2013
Embry-Riddle Aeronautical University
Investigation Of Pulse Detonation Engines; Theory, Design And Analysis, Jeff Vizcaino
Doctoral Dissertations and Master's Theses
Detonation and constant volume combustion has been known to the scientific community for some time but only recently has active research been done into its applications. Detonation based engines have received much attention in the last two decades because of its simple design and potential benefits to the aerospace industry. It is then the goal of this study to provide a background into detonation theory and application and establish the basis for future detonation based research at Embry-Riddle Aeronautical University. In this paper we will discuss the experimental aspects of building, testing, and analysis of a pulsed detonation tube …
Nonlinearity Index Analysis Of Periodic-Chaotic Stall-Spin Aircraft Motion,
2013
Old Dominion University
Nonlinearity Index Analysis Of Periodic-Chaotic Stall-Spin Aircraft Motion, Daniel Paul Tapolcai
Mechanical & Aerospace Engineering Theses & Dissertations
This thesis explores the application of nonlinearity index theory to the nature of stalling and spinning aircraft motions. Nonlinear dynamic phenomena related to stall and spin have been a concern to flight engineers and pilots for generations. Considerable past work has been directed to detect and understand the cause and nature of these phenomena. Methods such as bifurcation analysis, Volterra expansion series, and nonlinear simulation are a few of the nonlinear approaches developed to study this topic. Traditionally, however, linear analysis is the most widely used approach for studying aircraft dynamical behavior under a given set of acceptable conditions. This …
Characterization Of A Spiral Microfluidic Focusing Device For Continuous Single Cell Impedance-Based Cytometry Applications,
2013
Old Dominion University
Characterization Of A Spiral Microfluidic Focusing Device For Continuous Single Cell Impedance-Based Cytometry Applications, Daniel Riley
Mechanical & Aerospace Engineering Theses & Dissertations
A major focus in the field of cell characterization is the quantification of cell dielectric properties in order to develop low-cost, portable microfluidic devices that can, among other things, perform point-of-care detection of rare diseases and complete blood counts. Impedance-based cytometry has become an advantageous tool to ascertain these properties, wherein it is important that cells pass through the same point in a channel cross-section one at a time to ensure accurate and repeatable readings. This study documents the assessment of an 8-loop 160 μm (W) x 80 μm (H) spiral microchannel used to focus 10 μm polystyrene particles. In …
Design And Performance Of Circulation Control Geometries,
2013
California Polytechnic State University, San Luis Obispo
Design And Performance Of Circulation Control Geometries, Rory Martin Golden
Master's Theses
With the pursuit of more advanced and environmentally-friendly technologies of today’s society, the airline industry has been pushed further to investigate solutions that will reduce airport noise and congestion, cut down on emissions, and improve the overall performance of aircraft. These items directly influence airport size (runway length), flight patterns in the community surrounding the airport, cruise speed, and many other aircraft design considerations which are setting the requirements for next generation aircraft. Leading the research in this movement is NASA, which has set specific goals for the next generation regional airliners and has categorized the designs that meet the …
Comparison Of Models For Mixture Transport Properties For Numerical Simulations Of Ablative Heat-Shields,
2013
University of Michigan
Comparison Of Models For Mixture Transport Properties For Numerical Simulations Of Ablative Heat-Shields, Hicham Alkandry, Iain D. Boyd, Alexandre Martin
Mechanical Engineering Faculty Publications
The goal of this study is to evaluate the effects of different models for calculating the mixture transport properties on flowfield predictions of ablative heat-shields. The Stardust sample return capsule at four different trajectory conditions is used as a test case for this study. In the first part of the study, the results predicted using Wilke's mixing rule with species viscosities calculated using Blottner's curve fits and species thermal conductivities determined using Eucken's relation are compared to the results obtained using Gupta's mixing rule with collision cross-section (CCS) data. The Wilke/Blottner/Eucken model overpredicts the heat transfer to the surface relative …
Investigation Of Turbulent Structure Modification By Momentum Injection Into Turbulent Flow Over A Rough Surface,
2013
University of Kentucky
Investigation Of Turbulent Structure Modification By Momentum Injection Into Turbulent Flow Over A Rough Surface, Mark A. Miller, Huaibao Zhang, Alexandre Martin, Sean C. C. Bailey
Mechanical Engineering Faculty Publications
Utilizing a turbulent channel flow facility, experiments were performed to determine the modifications made to the temporal and spatial structure of turbulence over a sinusoidally rough surface due to momentum injection through the surface. As expected, when compared to the smooth-walled conditions, it was found that the surface roughness increased wall shear stress, decreased the turbulence energy content near the wall, and shifted that energy content to wavelengths on the order of the roughness elements. The addition of momentum injection was found to produce further modifications analogous to increasing the roughness height by increasing the wall shear stress and further …
Modeling Of Chemical Nonequilibrium Effects In A Charring Ablator,
2013
University of Kentucky
Modeling Of Chemical Nonequilibrium Effects In A Charring Ablator, Alexandre Martin
Mechanical Engineering Faculty Publications
Charring ablators remain the premium choice for space exploration missions that involve atmospheric re-entry. These type of ablative material are composed of a carbon matrix, usually made of fibers, which is then impregnated with a resin. During re-entry, the high heat flux produced by convective heating causes the material to chemically react. First, the resin pyrolyzes, and is vaporized into a gas that travels through the material, and is eventually ejected at the surface. Since the composition of the gas at the surface greatly affects the heat flux, and therefore the surface temperature, it is thus important to be able …
Non-Equilibrium Pressure Control Of The Height Of A Large-Scale, Ground-Coupled, Rotating Fluid Column,
2013
Old Dominion University
Non-Equilibrium Pressure Control Of The Height Of A Large-Scale, Ground-Coupled, Rotating Fluid Column, R. L. Ash, I. R. Zardadhkan
Mechanical & Aerospace Engineering Faculty Publications
When a ground-coupled, rotating fluid column is modeled incorporating non-equilibrium pressure forces in the Navier-Stokes equations, a new exact solution results. The solution has been obtained in a similar manner to the classical equilibrium solution. Unlike the infinite-height, classical solution, the non-equilibrium pressure solution yields a ground-coupled rotating fluid column of finite height. A viscous, non-equilibrium Rankine vortex velocity distribution, developed previously, was used to demonstrate how the viscous and non-equilibrium pressure gradient forces, arising in the vicinity of the velocity gradient discontinuity that is present in the classical Rankine vortex model, effectively isolate the rotating central fluid column from …
Experimental Characterization Of Roughness And Flow Injection Effects In A High Reynolds Number Turbulent Channel,
2013
University of Kentucky
Experimental Characterization Of Roughness And Flow Injection Effects In A High Reynolds Number Turbulent Channel, Mark A. Miller
Theses and Dissertations--Mechanical and Aerospace Engineering
A turbulent channel flow was used to study the scaling of the combined effects of roughness and flow injection on the mean flow and turbulence statistics of turbulent plane Poiseuille flow. It was found that the additional momentum injected through the rough surface acted primarily to enhance the roughness effects and, with respect to the mean flow, blowing produced similar mean flow effects as increasing the roughness height. This was not found to hold for the turbulence statistics, as a departure from Townsend’s hypothesis was seen. Instead, the resulting outer-scaled streamwise Reynolds stress for cases with roughness and blowing deviated …
Near Wall Shear Stress Modification Using An Active Piezoelectric Nanowire Surface,
2013
University of Kentucky
Near Wall Shear Stress Modification Using An Active Piezoelectric Nanowire Surface, Christopher R. Guskey
Theses and Dissertations--Mechanical and Aerospace Engineering
An experimental study was conducted to explore the possible application of dynamically actuated nanowires to effectively disturb the wall layer in fully developed, turbulent channel flow. Actuated nanowires have the potential to be used for the mixing and filtering of chemicals, enhancing convective heat transfer and reducing drag. The first experimental evidence is presented suggesting it is possible to manipulate and subsequently control turbulent flow structures with active nanowires. An array of rigid, ultra-long (40 μm) TiO2 nanowires was fabricated and installed in the bounding wall of turbulent channel flow then oscillated using an attached piezoelectric actuator. Flow velocity …
