AAE senior Adam Patel has been evaluating the performance of alternative propellants in Hall thrusters, the focus of his winning poster. 

Two AAE seniors won poster awards at the research symposium at the conclusion of the Summer Undergraduate Research Fellowship (SURF) program.

Richard Brookes won for “Flow Measurement Using Electron Beam Fluorescence” in Flow Analysis and Processing, and Adam Patel’s poster, “Experimental Evaluation of a Krypton Propellant Arrangement in a T-100-3 Hall-Effect Thruster,” won in Combustion and Energy. Only 10 winning posters were selected among nearly 90 participants who presented at the end of the Purdue program.

Brookes’s research emphasizes using a focused beam of electrons to “excite” a flowing gas – to make it glow – and that enables taking quantitative measurements of density, velocity, temperature, and gas composition.

Measurement of low-density gas flows by traditional methods often is not possible, Brookes says, so to yield new information about gas behavior at low densities, the technique of electron beam fluorescence is being re-evaluated.

“The main goal is to measure very low-density, high-speed flows,” says Brookes, whose research was conducted under the guidance of AAE Professor Alina Alexeenko. “These are very important to many fields, including hypersonics, spacecraft thrusters, and atmospheric re-entry studies.”

Patel’s focus is on electric propulsion, specifically evaluating the performance of alternative propellants in Hall thrusters in the Applied Plasma Science Lab under AAE Assistant Professor Alexey Shashurin. The Lab recently acquired a T-100-3 Hall effect thruster (HET) for experimentation. After repairing the damaged T-100-3, the team realized only xenon-propellant data on the thruster was readily available. No comprehensive studies had been published with alternative krypton propellant. So Patel has worked on evaluating the feasibility of krypton in Hall thrusters.

Richard Brookes, a senior in AAE, does research that emphasizes using a focused beam of electrons to “excite” (make glow) a flowing gas to take quantitative measurements.

“Krypton appears to be the most promising substitute for pre-existing systems,” Patel says. “It is 10 times more common in the atmosphere and nearly six times cheaper than xenon. Theoretically, the low mass of this propellant also holds significant specific impulse advantages.”

The project will continue over the course of the next academic year, Patel says, as he and the team continue to evaluate several parameters to determine performance. They include: Discharge voltage, discharge current, erosion, temperature, thrust, efficiency, specific impulse, plume distributions, and ion flux.

“The concept of electric propulsion focuses on an efficiency measure called specific impulse,” Patel says. “You can think of this parameter like miles per gallon in cars. In this analogy, an electric propulsion unit is a Prius and a conventional chemical rocket is a Corvette. Although the Prius is less powerful than the Corvette, it can go farther with the same amount of fuel. Hall thrusters work in this sense -- low power but high specific impulse. In terms of practicality, these systems have been historically used for satellite transfer. However, the technology shows great promise for interplanetary travel, such as Mars, in shorter amounts of time.”