AE Brown Bag Seminar
Friday, April 18
11:00 a.m.
Guggenheim 442
Pizza Served
Walker Brown
Wilson Fisher
Michael Francesconi
Charles McNabb
Emma Mobley
Nicolas Montero
Frederik von Klitzing
Walker Brown
Title:
Rocket Propellant Tank Fuel Sloshing and the Importance of Learning the Hard Way
Abstract:
Dr. Romero Calvo’s LGST (Low Gravity Science and Technology) lab over the past 3 years has worked to demonstrate a practical, real-world experiment demonstrating slosh dynamics in a rocket. With one successful launch and another coming soon, the team aims to demonstrate that real-life liquid sloshing (in a rocket propellant tank, for example) follows specific mathematical models that can be simulated. This seminar aims to track the evolution of this project from its inception to its current state, emphasizing how failure and hard lessons allowed the team to grow into competent and successful engineers.
Faculty Advisor:
Professor Álvaro Romero-Calvo
Wilson Fisher
Title:
Dispersion Analysis for Performance Characterization of MPDTs
Abstract:
With the continued emergence of electric propulsion as an alternative for traditional solid or liquid propulsive options, magnetoplasmadynamic (MPD) thrusters have specifically proven to be promising candidates due to high exhaust velocity and thrust density generation capabilities. However, efficiently and accurately characterizing the performance of these devices is still challenging and requires precise optical diagnostic setups to produce any coherent data for analysis. This research investigates the utilization of established dispersion relations for various electrostatic and electromagnetic waves to predict the prevalence of instabilities within the plasma plume for a coaxial MPD thruster under its predicted operating conditions. Initial results indicate a presence and potential propagation of electromagnetic waves – mainly magnetosonic, Alfvén, and whistler waves – as well as electrostatic lower hybrid oscillations and ion acoustic waves. Linking these dispersion characteristics to the plasma physics of the thruster allows for a reliable expectation that can be compared to experimental results from laser readings, ensuring proper data procurement and processing alongside general validity of the measurements. Future research will aim to extend an existing electrostatic dispersion relation for Hall Effect thrusters to the MPD case, applying the plasma dispersion function, the Gordeyev function, and various forms of the Bessel function to numerically represent the complex behavior inside the plasma plume when exposed to electromagnetic forces, providing a more high-fidelity analysis on the internal dynamics of the MPDT.
Faculty Advisor:
Professor Sedina Tsikata
Michael Francesconi
Title:
Inter-turbine combustion
Abstract:
The goal of inter-turbine combustion is to raise the overall efficiency and energy output of gas-powered generators. This is achieved by placing a jet after the first turbine engine, adding energy back into the flow while the flow is still relatively hot and compressed. This project examines the feasibility of inter-turbine combustion and how varying the concentration of natural gas and hydrogen in the fuel effects the combustion process.
Faculty Advisor:
Research Engineer Benjamin Emerson
Charles McNabb
Title:
Applications of Modified Garabedian-McFadden Method for Inverse Airfoil Design
Abstract:
This study investigates the relationship between pressure coefficient distribution and airfoil shape within the context of computational fluid dynamics (CFD). Traditional airfoil design dictates that pressure coefficient distribution is the consequence of airfoil shape. Inverse design, however, argues the opposite: that airfoil shape can be generated based off of a designed pressure coefficient distribution. This allows one to have more control over the airfoil's aerodynamic characteristics (lift coefficient, laminarity, etc.). Inverse design can be accomplished by pairing multiple iterations of Modified Garabedian-McFadden Method (MGM) with a fluids "solver" such as Vortex Panel Method (VPM) or XFOIL. This presentation will discuss the methodology and applications of these various inverse design methods.
Faculty Advisor:
Professor Lakshmi N. Sankar
Emma Mobley
Title:
Utilizing Computational Fluid Dynamics to Characterize the Fundamental Sloshing Modes of a Cylindrical Fuel Tank
Abstract:
Sloshing in aerospace vehicles refers to the liquid movement that occurs in partially filled areas such as fuel tanks. This movement is often detrimental to the motion of the vehicle and can be mitigated through analysis of predicted fluid dynamics. The Sloshing Damping Team aims to characterize fluid motion through experimental means and, most recently, through computational fluid dynamics software. The following presentation will cover the fundamental theory, principles of motion, and boundary conditions used to simulate several cases of this sloshing in ANSYS Fluent.
Faculty Advisor:
Professor Álvaro Romero-Calvo
Nicolas Montero
Title:
High Current Density Operation of a 3-kW Hall Thruster on Krypton
Abstract:
Contrary to chemical propulsion, which employs propellent combustion to maneuver spacecraft, electric propulsion (EP) utilizes the application of electric and magnetic fields to ionize and accelerate a neutral propellant, such as krypton, to provide thrust. Currently, there exist upwards of 10,000 satellites orbiting Earth and over 500 exploratory spacecraft that rely on EP technology--advantages including high propellant utilization efficiency, extended mission durations, and greater mission flexibility/performance (high thrust maneuverability). Operating EP devices (i.e. Hall Effect thrusters) at higher thrust densities often result in greater thrusts for an identical thruster envelope and mass. Additionally, studies indicate that the theoretical limit on HET thrust density is orders of magnitude higher than current capabilities. However, while increasing thrust density is, historically, not easy, one method is to increase the current density of HET operation. In turn, this work will investigate HET operational performance as discharge current increases at standard, discharge voltage conditions.
Faculty Advisor:
Prof. Mitchell L.R. Walker (and Prof. Dan Lev)
Frederik Von Klitzing
Title:
Computational Analysis of a Supersonic Underexpanded Swirling Jet
Abstract:
The presentation covers the simulation of a supersonic underexpanded jet using the Generalized k-⍵ (GEKO) turbulence model in Ansys Fluent. The goal of this work is to complement experimental efforts and deepen the understanding of the complex dynamics governing supersonic swirling flows. The simulations are performed on a rotationally periodic quarter domain and the full domain to examine the influence of symmetry assumptions on the development of asymmetric flow structures. Numerical results are compared against Particle Image Velocimetry (PIV) data to assess the capability of the GEKO model in capturing the velocity field and flow structure. A structured mesh is applied in the shock-dominated regions to resolve sharp gradients, while unstructured meshing is used in the more geometrically complex mixing chamber. The implicit density-based solver is employed to handle the high-speed compressible flow, and mesh refinement was performed using the Ansys Fluent adaptive mesh refinement tool. The simulations show promising results in comparison with the PIV data. Differences in jet decay behavior between the two domains highlight the sensitivity of the flow to domain symmetry. Future work will explore Detached Eddy Simulation (DES) and Large Eddy Simulation (LES) approaches to more accurately resolve unsteady flow features and further improve modeling fidelity.
Faculty Advisor:
Professor Adam Steinberg