Propulsion and Power Commons^™

Understanding The Nonlinear Dynamics Governing Vertical-Lift Vehicles With Variable-Speed, Fixed Rotors, Stephanie Vavra, Micah Busboom, Aleea Stanford, Keegan Moore

UNL Student Research Days Posters, Undergraduate

Problem: Traffic significantly limits travel in urban areas. • The NASA Urban Air Mobility Project is developing an air taxi as an alternative mean of transportation (Fig. 1).

Challenge: Operating rotors at different frequencies may cause the cabin to vibrate at high amplitudes. Such effects are currently unknown.

Objective: Understand the effect of variable speed rotors on passenger comfort.

From the reduced-order modeling simulations, it can be assumed that counteracting the rotor speed in-balances can reduce the displacement and vibrations experienced at the center of the wing. In other words, should a rotor not maintain its optimal operation speed, reducing …

Cfd Simulation Of Varying Fuel Jet Placement Of Mach 2 Flow (Paper), Sara Broad

Honors Capstone Projects

Supersonic flow is a concept that has been researched heavily for the past twenty years. It has many applications, with the most notable one being for the defense industry. This project specifically is based off a model that is being currently used for Air Force research. With supersonic flow, where the Mach number is larger than one, there has been continual research specifically on flameholders. Flameholders involve the discussion of the mixing, ignition, and combustion of the fuel that is released into the lower cavity of the scramjet. There is a current standard for the placement of fuel jets, but …

Investigation Of The Low-Temperature Combustion Phenomena Of A Fischer-Tropsch Synthetic Aerospace Fuel In A Constant Volume Combustion Chamber For Greenhouse Gas Reduction, Lily H. Parker

Honors College Theses

Greenhouse gases (GHG) have a harmful effect on our environment as they trap heat in the atmosphere accelerating climate change. As such, the Federal Aviation Administration’s 2025 strategic plan to reduce GHG emissions from air transportation. This call to action for a more environmentally friendly option highlights the importance of synthetic fuels as they are more sustainable compared to traditional fossil fuels. An investigation was conducted into the thermal-physical properties of Synthetic Fischer-Tropsch (F-T) Sustainable Aviation Fuels (SAF) and the Low Temperature Combustion (LTC). LTC is composed of the Low Temperature Heat Release (LTHR) and Negative Temperature Coefficient (NTC) region, …

Manufacturing Of A Ceramic Turbine Rotor For A Compact Jet Engine, Bryan T. Leicht

Theses and Dissertations

The primary goal of this study was to develop a low-cost, timely, scalable manufacturing method that produced a ceramic turbine that can be tested as a drop-in replacement on a JetCat P400 small scale gas turbine engine. This research compared two processes for manufacturing a ceramic turbine utilizing a pour casting method and 3D printing using stereolithography ceramic manufacturing (SLCM). The pour casting method used Silicon Nitride to create a cast turbine using a sacrificial 3D printed mold. The SLCM method evaluated producing an alumina turbine using an ADMATEC Admaflex 300 SLCM printer to directly print a ceramic turbine. This …

Design And Application Of Compact Combustors In Small-Scale Jetcat Engines, Nathan A. Clark

Theses and Dissertations

Ultra-compact combustors (UCC) are an innovative approach to improving overall engine efficiency and thrust-to-weight ratio by reducing the axial length and weight of the engine. Previous efforts looked at integrating a UCC into a small-scale JetCat P90 engine utilizing gaseous propane fuel. The current investigation aimed to utilize the previous compact combustor design and switch fuels to liquid kerosene. Based on the results from testing, a new combustor was designed equipped with a different flame holding mechanism at the larger P400-scale while maintaining a length savings of 20%. Testing of the P400 compact combustors was performed within a newly designed …

Design Of An Electro-Thermal Nanosatellite Propulsion System, James H. Founds

Theses and Dissertations

This research focused on designing an arcjet system with water as the propellant. Previous research developed a compact, reliable, and safe propellant storage and feed system. The goal is to combine the arcjet with the previous tank to achieve thrust and specific impulse characteristics greater than cold gas or resistojet system. This platform features a 1 U, non-hazardous, and sub-kilowatt powered propulsion system for nanosatellites. A simplified analysis of the design predicts thrust and specific impulse greater than can be achieved by cold gas or resistojet thrusters. Testing resulted in oxidation of the electrodes raising concerns about the longevity of …

Flow And Heat Transfer Characteristics In A Pre-Swirl Rotor-Stator Cavity, Xiaoyu Yang, Zhong Ren, Jing Ren, Philip M. Ligrani

PRC-Affiliated Research

The present study investigates flow and heat transfer characteristics in a rotor-stator pre-swirl system. Considered are rotational Reynolds numbers ReФ ranging from 3.4 × 105 to 6.8 × 105, with jet Reynolds numbers Rew of approximately 8.8 × 104 to 3.81 × 105, and associated turbulent flow parameter λT = Cw/ReФ0.8 varying from 0 to 0.4. Experimentally-measured and numerically-predicted results illustrate the combined and separate influences of jet impingement and rotor entrainment, as they affect and govern flow and heat transfer characteristics within the cavity. These results show that the relative strength of the two effects varies with ReФ and …

Analysis Of Nozzle Expansion Characteristics In Supersonic Retro-Propulsion, Gonzalo Montoya

Honors Undergraduate Theses

Supersonic retro-propulsion (SRP) is defined as rocket propulsion used to decelerate aerospace vehicles at supersonic speed. SRP is often used as a method of high-speed deceleration on space vehicles. The main method of propulsion used in the application of SRP is rocket propulsion. Rocket engine thrust and performance changes with altitude and expansion ratio. Changing altitudes across the trajectory of a rocket affect how the exhaust plume shock waves expand. Being able to identify how different expansion ratios affect the exhaust plume flow fields would provide useful data on how SRP performance can be predicted. This research projects aims at …

Extreme-Pressure Ignition Studies Of Methane And Natural Gas With Co2 With Applications In Rockets And Gas Turbines, Cory Kinney

Electronic Theses and Dissertations, 2020-2023

Although concerns about carbon dioxide (CO2) emissions and their impact on climate change has led to an increase in renewable energy electricity generation, natural gas power plants remain the dominant source of electricity generation in the United States. Until the capacity of renewable energy sources can meet growing electricity demand, natural gas power generation will likely remain an important source of electricity generation. Supercritical CO2 (sCO2) power generation cycles offer an alternative to traditional gas turbines by reusing and sequestering CO2 from the combustion process to prevent its release into the atmosphere. This study seeks to understand natural gas ignition …

Characteristics Of Rotating Detonation Engines For Propulsion And Power Generation, Robert Burke

Electronic Theses and Dissertations, 2020-2023

Conventional engines are limited by the efficiency of their combustion mode. Compared to present constant pressure deflagration-based engines, detonation-based systems can realize a higher thermodynamic cycle efficiency, making them an attractive candidate for next generation propulsion systems that will take humanity to hypersonic speeds and even to Mars. For all its performance gains, detonation engines are still far off from implementation. One system, the rotating detonation engine (RDE) is promising as a detonation-based engine concept for its stability, simplicity, and versatility. For these reasons, RDEs have been the subject of studies internationally in efforts to understand their operation and integration …

Thrust Augmentation Of Rotating Detonation Rocket Engines, Alexander G. Rodriguez

Honors Undergraduate Theses

This thesis aims to perform a detailed analysis on a 5th Order Polynomial Nozzle, verifying its effectiveness in improving the thrust performance of a Rotating Detonation Rocket Engine. Rotating detonation engines are a promising engine type that uses detonations as a means of combustion rather than traditional conflagration. Through this method, these engines can produce significant amounts of energy while burning less fuel in the process. However, exhaust flow instabilities and swirl limit the engine's potential for use as a means of propulsion. The 5th Order Polynomial Nozzle was previously demonstrated to reduce and control this swirl; however, analysis was …

On Liquid Rotating Detonation Rocket Engines Characterization And Performance, Vidhan Malik

Electronic Theses and Dissertations, 2020-2023

The current research investigates a next-generation method of combustion called detonations for propulsive applications which has support from the Combustion Services Branch at the Air Force Research Laboratory (AFRL) of the Rocket Propulsion Division. The overall initiative seeks to explore the viability of detonation-based systems to augment or replace current rocket propulsion methods in the coming five years. The present work progresses this vision by providing proof of a liquid RP-2 based Rotating Detonation Rocket Engine (RDRE) as well as the fundamentals associated with the physics involved to further the understanding of the phenomenon and its potential uses. Phase one …

Exploration Of Shock-Droplet Ignition And Combustion, John Patten

Electronic Theses and Dissertations, 2020-2023

Liquid fuels are desirable in aerospace applications due to their higher energy density when compared to gaseous fuels. With the advent of detonation-based engines, it is necessary to characterize and analyze how liquid fuel interacts with detonation waves as well as shocks to ignite. While liquid fuel sprays have been proven to successfully aid and sustain detonations, the physical mechanism by which the individual liquid droplets accomplish this is yet to be understood. Such knowledge allows for more predictable detonation properties, which in turn can let detonation-based engines be sustained more easily. This research seeks to quantify and characterize interactions …

Liquid Engine External Pressurizer (Leep), Emily Armbrust

Williams Honors College, Honors Research Projects

The purpose of this project is to take the current liquid rocket engine test stand design and implement an external pressurant instead of utilizing the 2-phase oxidizer vapor to pressurize itself and the fuel. The purpose behind the design is because the team is limited with the current design concerning burn time due to the amount of propellant they can put in the tanks and the pressure it can reach. The initial pressure is currently not held since there is no external input of mass into the tanks, as the propellant is leaving. Adding an external pressurant allow for the …

Large, Complex Housing, Alyssa Carnicella

Williams Honors College, Honors Research Projects

The purpose of this capstone project was to develop a design for a High Voltage Direct Current (HVDC) generator housing with built-in passageways for oil to flow through and cool the machine. The machine should be made using advanced manufacturing. A 3D model concept was designed with the use of SolidWorks. The appropriate hand calculations were completed to ensure that the generator housing would contain the components within itself under various environmental conditions.. The model was then 3D printed to produce a prototype that displays the design features within the housing. The next stage of the project will include completing …

Concept Evaluation And Development Of A Novel Approach For Integration Of Turbogeneration, Electrification And Supercharging On Heavy Duty Engines, Satyum Joshi

Dissertations, Master's Theses and Master's Reports

While many technologies such as electrically assisted turbocharging, exhaust energy recovery and mild hybridization have already proven to significantly increase heavy-duty engine efficiency, the key challenge to their widespread adoption has been their cost effectiveness and packaging. This research specifically addresses these challenges through evaluation and development of a novel technology concept termed as the Integrated Turbogeneration, Electrification and Supercharging (ITES) system. The concept integrates a secondary compressor, a turbocompound/expander turbine and an electric motor through a planetary gearset into the engine cranktrain. The approach enables a reduced system cost and space-claim, while maximizing the efficiency benefits of independent technologies. …

Investigations Of The Low Temperature Combustion Regions And Emissions Characteristics Of Aerospace F24 In A Constant Volume Combustion Chamber And A Common Rail Direct Injection Ci Engine, Richard C. Smith Iii

College of Graduate Studies: Theses & Dissertations

A study was conducted to investigate the low temperature combustion (LTC) regions of aerospace F24 and ULSD in the static setting of a CVCC and the dynamic setting of a CRDI research engine. This research is conducted to reduce in-cylinder emissions by understanding and implementing a technique to achieve an extended LTC. Emissions data for this study were collected during the operation of the CRDI research engine with a MKS 2030 FTIR and an AVL Microsoot 483. The parameters researched within the static setting of the CVCC included the determinations of the cool flames and NTC regions within the LTHR …

A Non-Reacting Passive Scalar Comparison Of Starccm And Openfoam In A Supersonic Cavity Flame Holder, Thomas Nuese

Electronic Theses and Dissertations

The scramjet engine equipped with a modern-day airliner would allow for very quick travel across the United States. The major problem is that designing such an engine and testing it to make sure it is safe would cost millions if not billions of dollars. Computational fluid dynamics allows for complex designs to be tested but can still take many days, weeks, or even months to complete. With the use of computational fluid dynamics (CFD), the scramjet engine can be analyzed to determine a quicker way to test and develop a reliable configuration in addition to analyzing the effects of different …

Development And Verification Of Flight Data Informed Performance Estimation And Prediction Simulation Tool For Small Electrical Multi-Rotor Uav, Nicholas Scott Borelle

Graduate Theses, Dissertations, and Problem Reports (ETD)

While small scale multi-rotor aircraft are becoming an increasingly large market with applications emerging every day, their ability to have both a high endurance/long range and a high speed/performance flight is severely limited. This leads to uncertainty in mission planning and aircraft design, specifically when deciding mission length and available on-board energy. Uncertainty like this leads to an increased chance of failure to complete the mission, and a failure to recover the aircraft. Considering that these aircraft are used by everyone from hobbyists to commercial companies to military personnel, the applications and missions being flown carry importance and a serious …

Cfd And Heat Transfer Analysis Of Rocket Cooling Techniques On An Aerospike Nozzle, Geoffrey Sullivan

College of Graduate Studies: Theses & Dissertations

In recent years the development of rocket engines has been mainly focused on improving the engine cycle and creating new fuels. Rocket nozzle design has not been changed since the late 1960s. Recent needs for reliable and reusable rockets, as well as advancements in additive manufacturing, have brought new interest into the aerospike nozzle concept. This nozzle is a type of altitude adjusting nozzle that is up to 90% more efficient than bell nozzles at low altitudes and spends up to 30% less fuel. Since the nozzle body is submerged in the hot exhaust gasses it is difficult to keep …