Aerospace Engineering Commons^™

Advanced Thermal Protection Systems (Tps) And Transition Analysis: Unique Experimental Capabilities And Current Research Efforts At The University Of Texas At Arlington, Matthew Crisanti, Cody Ground, Stefano Gulli, Jared Poempipatana, Luca Maddalena

Ablation Workshop

A unique experimental capability in the academic panorama is the 1.6 MW-classic arc-jet facility located at the Aerodynamics Research Center of the University of Texas at Arlington. The arc-heated wind tunnel has recently been refurbished and repurposed (extended testing time of the order of minutes and testing gas-composition control) for the study and characterization of the aerothermal response of TPS candidate materials for sustained hypersonic flight.

Experimental Investigation Of Blowing Effects On Turbulent Flow Over A Rough Surface, Mark A. Miller, Sean C. C. Bailey, Alexandre Martin

Ablation Workshop

Entry of spacecraft into an atmosphere occurs at hypersonic speeds, extremely complex flow fields, with aerothermodynamic effects which can cause the surface to be subjected to extreme heating. It is therefore important to protect the vehicle and its payload using a thermal protection system (TPS). Heat shields, which are an important part of a TPS, can be of either ablative or non-ablative types. For an ablative TPS, the energy is dissipated through surface material charring and ablation, as well as releasing gasses which serve to carry energy away from the TPS and thus reduce the total heat flux into the …

Computational Chemistry Modelling Of The Oxidation Of Highly Oriented Pyrolitic Graphite (Hopg), Savio Poovathingal, Thomas E. Schwartzentruber

Ablation Workshop

Under high heat flux, carbon based Thermal Protection Systems (TPS) are observed to rapidly ablate and an accurate characterization is essential to their design. Dissociated oxygen atoms (from the gas phase) striking the surface of TPS could lead to several possibilites. The O atom could adsorb on the surface, recombine with another O atom to form O2 and oxidize the surface to produce CO or CO2 resulting in recession of the surface (ablation). The goal is to predict finite rate models for these reactions which could be incorporated into CFD and DSMC solvers. Our efforts are to predict the rates …

Computation Of Surface Catalysis For Graphite Exposed To High Enthalpy Nitrogen Flow, Abhilasha Anna, Iain D. Boyd

Ablation Workshop

The high temperatures on a hypersonic vehicle surface caused by heat loads encountered during (re-)entry through a planetary atmosphere require a reliable Thermal Protection System (TPS) that makes a good understanding of the physical and chemical processes essential for its design. Surface catalysis is a crucial chemical process that directly impacts aerothermal heating of the vehicle TPS. The effects of surface catalysis for graphite exposed to high-enthalpy nitrogen flow are examined in this study.

Preparing Nasa For The 21st Century: Oct Perspective On Edl, Harry Partridge

Ablation Workshop

NASA’s Chief Technologist, within the Office of the Chief Technologist (OCT), is the principal advisor to the NASA Administrator in matters related to Agency-wide technology policy and programs and is responsible for the planning, advocacy and coordination of technology development activities within NASA to meet future mission needs. OCT works with the Mission Directorates and mission planners to infuse new technologies into future missions and with other Governmental Agencies to coordinate technology development efforts of mutual interest. In addition, OCT manages NASA’s Space Technology Program (STP), which also includes the SBIR and STTR programs. In this presentation OCT’s role within …

Introduction: The 5th Ablation Workshop And Beyond, Ioana Cozmuta, Alexandre Martin

Ablation Workshop

No abstract provided.

The Art And Beauty Of Flight, Edmond Ing Huang Tan

The Hilltop Review

This picture nicely represents the art and gracefulness of flight with the beauty of sunset in a tranquil setting. In the picture is a powered paragliding, also known as paramotoring in the plains of Nebraska. The ability to fly both low and slow safely, the 'open' feel, the minimal equipment and maintenance costs, the portability, minimally regulated and requires no license are claimed to be this type of flying's greatest merits. Paramotors can be flown during any season of the year anywhere but not in high wind conditions which typically means at low Sun azimuths as shown in the picture …

Microgas Turbine Engine Characteristics Using Biofuel, Edmond Ing Huang Tan, William W. Liou

The Hilltop Review

Aviation fuels commonly used today are extracted from the kerosene fraction of the crude oil that is distilled between the gasoline and the diesel. Crude oil is not renewable and the world oil reserve is generally believed to be on the decline. In 2006, 6.3% of the world's refinery production was used for aviation fuel (Nygren et. al., 2009). At an estimated rate of 3% increase of fuel demand per year, aviation use alone will consume the world fuel production by 2026. Therefore, there is a need for the aviation industry to reduce its dependence on fossil fuels and, perhaps, …

Modeling Small Unmanned Aerial System Mishaps Using Logistics Regression And Artificial Neural Networks, Sean E. Wolf

Theses and Dissertations

A dataset of 854 small unmanned aerial system (SUAS) flight experiments from 2005-2009 is analyzed to determine significant factors that contribute to mishaps. The data from 29 airframes of different designs and technology readiness levels were aggregated. 20 measured parameters from each flight experiment are investigated, including wind speed, pilot experience, number of prior flights, pilot currency, etc. Outcomes of failures (loss of flight data) and damage (injury to airframe) are classified by logistic regression modeling and artificial neural network analysis. From the analysis, it can be concluded that SUAS damage is a random event that cannot be predicted with …

Ablation Test-Case Series #2. Numerical Simulation Of Ablative-Material Response: Code And Model Comparisons, Jean R. Lachaud, Alexandre Martin, Tom Van Eekelen, Ioana Cozmuta

Mechanical Engineering Faculty Publications

This test-case series on the numerical simulation of the response of ablative-materials really started out of pure curiosity. Code developers and users were curious to see "how the codes compare" and "what is the effect of the different hypotheses in the models implemented". The objective of these test-case series is to propose problems of increasing complexity until it is agreed that the most-elaborated well-defined problem is formulated. The first test-case was mostly a simple heat transfer problem chosen for it’s simplicity (it is summarized in section 2.1). The second test-case series goes one step further, with the objective of reaching …

Ablation Test-Case Series #3. Numerical Simulation Of Ablative-Material Response: Code And Model Comparisons, Tom Van Eekelen, Jean R. Lachaud, Alexandre Martin, Ioana Cozmuta

Mechanical Engineering Faculty Publications

The test-case series #3 will be a further extension of the tests defined within the framework of the NASA ablation modelling workshops. In order to reduce the amount of work, all tests within test-case series #3, will use the TACOT material defined by Lachaud et al. The main goal of this new series, is to test the 3D modelling capabilities of the participating codes. The first 1D results were presented at the 4th Ablation workshop, and together with the results of the second test-case series, will be discussed and analyzed more thoroughly at the 5th Ablation Workshop, Feb. 28- March …

Pico-Satellite Integrated System Level Test Program, Marcus A. Ruddy

Master's Theses

Testing is an integral part of a satellite’s development, requirements verification and risk mitigation efforts. A robust test program serves to verify construction, integration and assembly workmanship, ensures component, subsystem and system level functionality and reduces risk of mission or capability loss on orbit.

The objective of this thesis was to develop a detailed test program for pico-satellites with a focus on the Cal Poly CubeSat architecture. The test program established a testing baseline from which other programs or users could tailor to meet their needs. Inclusive of the test program was a detailed decomposition of discrete and derived test …

Experimental Investigation Of Suction Slot Geometry On A Goldschmied Propulsor, Nicole M. Thomason

Master's Theses

The Goldschmied Propulsor concept combines boundary layer suction and boundary layer ingestion to improve propulsive efficiency and reduce drag on an axisymmetric body. This investigation of a Goldschmied Propulsor aimed to determine influential characteristics of the suction slot geometry to aid in better slot geometry design and to decrease the suction flow requirements for maintaining attached flow over the entire model surface. The Propulsor model was 38.5 inches in length with a max diameter of 13.5 inches. Three suction slot geometries were investigated with the addition of aluminum cusps to the slot entrance. The cusps varied in the distance they …

Design And Analysis Of A Reusable N2o-Cooled Aerospike Nozzle For Labscale Hybrid Rocket Motor Testing, Daniel Joseph Grieb

Master's Theses

A reusable oxidizer-cooled annular aerospike nozzle was designed for testing on a labscale PMMA-N₂0[1] hybrid rocket motor at Cal Poly-SLO.[2] The detailed design was based on the results of previous research involving cold-flow testing of annular aerospike nozzles and hot-flow testing of oxidizer-cooled converging-diverging nozzles. In the design, nitrous oxide is routed to the aerospike through a tube that runs up the middle of the combustion chamber. The solid fuel is arranged in an annular configuration, with a solid cylinder of fuel in the center of the combustion chamber and a hollow cylinder of fuel lining …

Dynamic Model Creation And Scripting Support In The Horizon Simulation Framework, Brian Jeffrey Butler

Master's Theses

Dynamic model creation and support for the Lua scripting language was added to the Horizon Simulation Framework used for the verification and validation of system-level requirements. The addition of scripting support allows for subsystem models and their algorithms to be defined using a simpler scripting language, rather than C++. The Luabind library by Rasterbind software is used to expose the C++ algorithms and classes to Lua that are already defined in the framework. Interoperability between Lua and C++ code allows for the ease of use of a scripting language while utilizing the utility classes and functions already created. The dynamic …

Study Of Turbulence-Radiation Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, M. P. Martín, A. M. Feldick, M. F. Modest, D. A. Levin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Direct numerical simulations are conducted to investigate the effect of turbulence-radiation interaction in hypersonic turbulent boundary layers, representative of the Orion crew exploration vehicle at the peak heating condition during reentry. Both the effects of emission and absorption are considered by solving the radiative transfer equation using the tangent slab approximation and a spectral model with line-by-line accuracy. Nondimensional governing parameters to measure the significance of turbulence-radiation interaction are proposed, and the direct numerical simulation fields with and without radiation coupling are used to assess turbulence-radiation interaction. Is it found that the fluid medium within the boundary layer is optically …

The Effect Of Elevated Temperature On The Inelastic Deformation Behavior Of Pmr-15 Solid Polymer, Chad E. C. Ryther

Theses and Dissertations

The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at temperatures in the 274-316°C range. The experimental program was developed to explore the influence of temperature on tensile loading, relaxation and creep behaviors of PMR-15. The results demonstrate that the mechanical behavior of PMR-15 exhibits a strong dependence on temperature. During strain-controlled tensile loading, the slope of the stress-strain curve in the quasi-elastic region decreases and the flow stress level decreases with increasing temperature. During relaxation, the amount of the stress drop decreases with increasing temperature. Based on experimental results the Viscoplasticity Based on Overstress …

Aircraft Operations Based Mission Requirements, Robert A. Mcdonald

Aerospace Engineering

The mission capabilities of aircraft in the current commercial fleet are a combined result of many factors. The launch customer for each aircraft has a voice in determining the requirements. The manufacturer desires to best position the aircraft in the market considering their own aircraft and their competitors aircraft it will replace and compete with. Consequently, anyone considering the development of an aircraft to compete with or replace an aircraft in-service must do more than simply choose to meet the capabilities of that aircraft. This is especially true when unconventional systems are considered; the fundamental trade-offs for these systems may …

High Performance Modeling Of Atmospheric Re-Entry Vehicles, Alexandre Martin, Leonardo C. Scalabrin, Iain D. Boyd

Mechanical Engineering Faculty Publications

Re-entry vehicles designed for space exploration are usually equipped with thermal protection systems made of ablative material. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain better predictions, an appropriate gas flow chemistry model needs …

Modeling Of Heat Transfer Attenuation By Ablative Gases During The Stardust Re-Entry, Alexandre Martin, Iain D. Boyd

Mechanical Engineering Faculty Publications

The great majority of modern space vehicles designed for planetary exploration use ablative materials to protect the payload against the high heating environment experienced during re-entry. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain …