Propulsion and Power Commons^™

Flame Boundary Effects Of Hydrogen-Air Premixing, Alecson L. De Lima Junior

Honors Undergraduate Theses

The objective of this research was to investigate the reaction of hydrogen and heated air premixing when injected into a combusting ethylene-air crossflow, and to study the flame stabilization location with varying premixing levels. The main parameter of this investigation was the flame stabilization diagnosed through chemiluminescence, based on recorded equivalence ratio, temperature, and flame boundaries, and maintaining a constant air temperature, hydrogen and air mass flow, and momentum flux ratios. Testing was conducted at different ratios of hydrogen and air premixing achieved through alternating the distance between the point where hydrogen and air are mixed and the combusting crossflow. …

Hybrid Rans-Les Analysis Of Turbulent Flame Under Near Blow-Off Condition In A Multi-Stage Swirl Combustor, Brandon O'Brien

College of Graduate Studies: Theses & Dissertations

Advances in computational resources are making computational fluid dynamics (CFD) increasingly accessible for a variety of engineering applications. However, certain complex problems, such as simulating detailed flame kinetics, remain computationally prohibitive for many users. Developing cost-effective methods to simulate these challenges would greatly benefit applications involving flame dynamics, such as turbine engines or industrial burners. This study investigates the effect of main stage swirler intensity on near lean blow-off characteristics in a multi-staged swirl combustor using Ansys Fluent. The hybrid RANS-LES turbulence model, Stress Blended Eddy Simulation (SBES) coupled with Flamelet Generated Manifold (FGM) combustion model was selected to model …

2024 Summer-Fall Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for summer and fall 2024. Includes photographs, upcoming events, recent publications, and student profiles.

Assessing General Propulsion Architectures For Fast Transit Times To Mars For Crewed Missions, Vivek Bhatt

Doctoral Dissertations and Master's Theses

As NASA and commercial contractors, such as SpaceX, continue to develop their programs with Artemis and Starship, respectively, it is becoming more and more apparent that the program developments are ultimately for finding a way to put humans onto Mars. However, when we approach the current timeline of going to Mars, it usually involves a 6-9 month one way trip. Due to this, human spaceflight to Mars becomes more dangerous as exposure to affects such as solar radiation, long exposure to low gravity fields, and isolation. These are some of the many hazards that come with interplanetary space travel for …

Design Of A Safe And Sustainable Airplane For Future, Henil Patel, Carlie Vogt, Matthew Talty, Jemimah Davies, Kyle Smothers, Mellisa Pritchet

Sustainability Conference

As a part of Airplane Preliminary Design course, this Design Note estimates the capabilities, performance, and stability behaviors of our conceptual airplane design, Boeing 7S7 – Sanctum prior to proceeding to the preliminary stage. This aircraft seeks to create a solution to achieving Net Zero Emissions by 2050 and increasing the safety measures. The design of this aircraft uses various analytical methods such as the DAPCA IV model, other methods were derived from design books. This design involved the use of software such as CATIA, VSP, SURFACES, Microsoft Excel, and Python. Results demonstrates that this aircraft is able to fly …

Unleaded Fuel For General Aviation, Carolina Anderson, Laura Garcia

Sustainability Conference

The Clean Air Act, passed in the late 1970s, mandating the removal of lead from most fuels due its detrimental effects on public health, yet piston-driven aircraft continue to rely on leaded aviation gas (AvGas 100LL). This fuel remains the last lead-containing fuel regulated by the Department of Transportation (DOT). Lead, added as tetraethyl lead (TEL), enhances octane levels and prevents engine detonation, vital for high-compression aircraft engines. In response to the health effects, regulating bodies like the Environmental Protection Agency (EPA) have tightened lead standards and are assessing the risk posed by AvGas. Research links even low-level lead exposure …

The Impact Of Film Cooling On The Heat Release Within A Rotating Detonation Combustor, Shreyas Ramanagar Sridhara, Antonio Andreini, Marc D. Polanka, Myles D. Bohon

Faculty Publications

Rotating detonation combustors establish a detonation wave that continuously circulates inside a small annulus. The presence of the detonation wave and the downstream oblique shock within the small annulus coupled with high mass flow induces a high heat load to the combustor wall. Preliminary analysis shows that for higher thermal power, internal air cooling alone is not sufficient to remove the heat out of the walls to maintain them below the maximum temperature of the metal. A possible solution is to use film cooling to reduce the heat flux to the combustor walls. One issue, though, is that the introduction …

Sunrise Propulsion Subsystem Leak Rate Measurement Methodology, Alex Kirkman, Brittany Woytko, Holly Walen, Bret Maughan

Space Dynamics Laboratory Publications

As part of the integration and testing for Sun Radio Interferometer Space Experiment (SunRISE), it was necessary to characterize the propellent leak rate of the fully assembled propulsion subsystem for each satellite to ensure compliance with performance requirements. SunRISE utilized a cold gas system for its propulsion subsystem, using R-236fa propellant inside a tank made from a monolithic 3D printed SLA material. It was not possible to accurately characterize the propellent leak rate via weight by measuring the mass loss from the tank. This is due to the SLA material having both a high absorbance rate of water in normal …

Spacecraft Attitude Control Simulator, Bricen S. Rigby

College of Engineering Summer Undergraduate Research Program

The Spacecraft Attitude Control Simulator is a single-axis attitude control platform which is intended to recreate the frictionless space environment in order to test cold-gas thruster control schemes. The overall goal of this research project was to observe settling data from the platform and compare it to simulated data. In practice, the predicted settling time was only 7% larger than observed settling time.

Cryogenic Fuel Applications To Sustainable Commercial Aircraft, Jack R. Kisling, Lillian Panning

College of Engineering Summer Undergraduate Research Program

Finding a source of clean and renewable energy is one of the greatest challenges humanity will face in the 21st century. With populations expanding, developing countries increasing their use of resources, and the rapid and alarming effects of climate change, a shift to a sustainable future is an existential prospect.

The goal of our project is to take the first steps toward getting safety procedures and lab space established, so mechanical engineering senior projects can quickly begin to experiment with cryogenic fuels. They will explore the application of cryogenic fuels to commercial aviation.

Computer Based Modeling For Small E-Vtol Propeller Performance, Ege Konuk

Mechanical & Aerospace Engineering Theses & Dissertations

The emerging field of urban air mobility (UAM) offers a novel transportation method for civil, commercial, and military applications. Vertical take-off and landing (VTOL) configurations present challenges for performance prediction during crucial flight operations. An advanced computational framework for predicting propeller performance in electric vertical takeoff and landing (eVTOL) aircraft during transition flight is essential for future concept designs. This research extends the Blade Element Momentum Theory (BEMT) to model propeller behavior at high incidence angles, crucial for eVTOL operation.

The study begins with a review of tilt-wing/rotor configurations for eVTOLs and tackles the complex aerodynamic phenomena associated with rotors …

Heat Transfer To Arrays Of Oscillating Impingement Jets, Alex Q. Clay

Doctoral Dissertations and Master's Theses

In gas turbine engines, the desire to increase turbine entry temperatures has become more relevant in order to increase engine efficiency. However, materials used in these engines can only withstand temperatures that are so high. Because of this, the ability to cool hot section components will always limit operating temperatures. Impingement cooling jets have become a common way of cooling due to the high rates of heat transfer that can be achieved. However, previous research has shown that the interaction of impingement jets with cylinder wake can improve the intensity and uniformity of heat transfer. The goal of this study …

Engine Performance Of An Electric Airplane With Partial Battery Capability, Hannah Yasmine Scrivens

Theses and Dissertations

As electric aircraft are developed and certified, knowledge of electric aircraft performance during complete or partial battery failures can be useful to determine an aircraft’s limitations and capabilities of completing an emergency landing, especially during takeoff and low-altitude climbs, as well as fully characterizing the potential aircraft performance. The results of this research will be useful in developing regulations and procedures pertaining to energy reserves and emergencies. This paper presents the results of a Pipistrel electric airplane climb power ground test that was conducted by the author and Florida Tech faculty. In the test, one of the airplane’s batteries was …

Disk Engine With Circumferential Swirl Radial Combustor, Brian T. Bohan, Marc D. Polanka, Bennett Staton

AFIT Patents

A disk engine and system configured to provide high power at a reduced axial length is disclosed herein. The disk engine includes a radial compressor, a compressor discharge manifold positioned circumferentially about compressor, a combustion chamber positioned within the discharge manifold and a radial turbine positioned radially inward of the combustion chamber.

A Model For Spacecraft Relative Motion Using Continuous Periodic Thrust, Philip Alan Hittepole

Dissertations

A model for modifying the relative orbit of a deputy satellite with respect to a chief satellite in a near-circular orbit using continuous periodic thrust is presented. This model is built on the Lovell-Spencer relative orbital elements (ROEs). The four linear ROEs (xr, yr, ar, and Az) can be linearly modified. The two angular ROEs (Er and ) can be set to advance at a desired, constant rate. Each ROE can be modified individually but may cause intra-orbit variations in other ROEs which return to their original values at the end of a thrust cycle. A method to easily calculate …

Rapid Response Satellite Launcher, Nathan Jones, Joey Cosentino, Jayson Layton, Afek Adar

Senior Design Project For Engineers

Air launch to orbit is a new style or spacecraft where rockets are attached to a large aircraft and released at cruising altitude to then ignite and launch into space. Companies such as Virgin Orbit are using it as a cheap and efficient way to move satellite payloads into lower or upper Earth orbit. These styles of launchers can be designed to be much smaller than ground-launched spacecraft, reducing cost and weight of the launcher in comparison. With many private companies coming into the space and satellite industry, the design and manufacturing of these launchers have become a focus within …

A Study Of Varying Dielectric Constant And Thickness Of Dielectric Barrier Discharge Devices And Their Subsequent Plasma Actuation, Sharon Kardasz

Mechanical Engineering Undergraduate Honors Theses

The principles of air-breathing ion propulsion are relatively unestablished in the aerodynamic realm as traditional forms of combustion for propulsion systems have remained in use. However, due to increasing environmental, economic, and efficiency concerns of traditional combustion, interests in innovative propulsion methodologies, such as electric propulsion, are emerging. A primary technology of interest for use of ion propulsion is the Dielectric Barrier Discharge Device (DBD). Preliminary research conducted at the University of Arkansas has determined the most favorable DBD geometry. This work will continue the preliminary research to decipher the most favorable DBD configuration by varying dielectric thickness and dielectric …

Modeling Of Rotor Wake Vortex Dynamics And Interactions In Non-Homogenous Vertiport Environments, Garrison P. Shaw

Doctoral Dissertations and Master's Theses

The current research serves to analyze and study the effects ground forces can have on the thrust performance of a propeller in multiple different configurations. The current research utilizes an open source Computational Fluid Dynamics (CFD) software known as OpenFOAM to generate calculate and visualize these runs. The model used for this experiment is a hybrid model that employs both a Unsteady Reynolds-Averaged Navier-Stokes (URANS) and a detached eddy simulation using a hybrid Large Eddy Simulation (LES) via a KomegaSSTDDES model. This model serves to save computational time as well as allow for accurate results. The three cases run are …

Development Of On-The-Fly Quasi-Steady State Approximation For Chemical Kinetics In Cfd, Abhinav Balamurugan

Doctoral Dissertations and Master's Theses

This study analyzes the feasibility of On-The-Fly Quasi-Steady-State Approximation (OTF-QSSA) application for solving chemical kinetics within Computational Fluid Dynamics (CFD) simulations, aiming to reduce the computational demand of detailed mechanisms. An algorithm that dynamically identifies and designates Quasi-Steady-State (QSS) species at specific grid locations and instances during the simulation was developed. With this information, our method pseudo-delays the advancement of concentrations for these QSS species—effectively setting their rate of concentration change to zero for a set number iteration before updating using the detailed mechanism and thereby omitting the computationally intensive processes typically required for their calculation during those skipped iteration. …

Mitigating Engine Unstart In Scramjets With Porous Bleeders, Ryan Lindley

Doctoral Dissertations and Master's Theses

The effectiveness of porous bleeders in mitigating unstart phenomena and enhancing isolator effectiveness in a hypersonic scramjet was investigated. Through computational fluid dynamics simulations, the impact of porous bleeder design parameters such as pressure jump coefficient and bleeder size on isolator effectiveness and unstart prevention was evaluated. Results indicated that porous bleeders delayed flow separation and reduced adverse pressure gradients, thereby enhancing isolator performance. Additionally, porous bleeders demonstrated promising capabilities in preventing full unstart events and mitigating oscillatory unstart phenomena.