UAH – News
Michael Mercier | UAH
A research paper on heat transfer inside the reactor of a conceptual liquid-fuel nuclear rocket engine by a graduate student at the University of Alabama at Huntsville (UAH) caused a stir at the recent American Nuclear Society’s Nuclear and Emerging Technologies for Space (NETS) conference, winning best student paper at the Cleveland event.
Winner Jacob Keese, a native of Valley Center, Kansas, is a sophomore in a master’s degree in mechanical engineering at UAH, part of the University of Alabama system. Keese is advised by Dr. Keith Hollingsworth, chair of the Department of Mechanical and Aerospace Engineering at UAH. This was the second year in a row that a UAH student won the Best Student Paper award at NETS.
Keese’s research was done as part of UAH investigations into a new concept of nuclear thermal spacecraft propulsion called Centrifugal Nuclear Thermal Propulsion (CNTP), where uranium fuel is spun in a chamber of combustion so that the centrifugal force holds it to the walls. The fuel heats to the point of liquefaction at temperatures close to those found on the sun, and then hydrogen gas bubbles into it. Hydrogen expansion powers the spacecraft.
With UAH’s distinguished systems engineering researcher, Dr. Dale Thomas as principal investigator, UAH is leading a collaboration of universities across the country to investigate the feasibility of such an engine as part of a research contract for the Space Nuclear Propulsion Project Office of NASA’s Marshall Space Flight. Center.
“My research involved creating a numerical model of the heat transfer and thermodynamic processes in the liquid fuel reactor,” Keese explains. “This is an advanced nuclear rocket concept that promises performance far superior to that of current rocket engines.” Keese’s modeling gives insight into the temperatures that can be reached in the reactor.
“That, in turn, will help us understand the performance potential of the rocket,” he says.
“My research applies primarily to advanced space missions that require very high performance rocket engines,” says Keese. “The CNTP concept promises improved specific impulse, which is essentially the efficiency of a rocket engine, like miles per gallon in a car.”
The concept could deliver up to three to four times the efficiency of traditional rocket engines and one-and-a-half to two times that of solid-fuel nuclear rocket engines currently under development, Keese said.
“This increased efficiency could be achieved without sacrificing high thrust, which could open the door to much more ambitious missions,” he says. “Some of the missions that have been proposed are human missions to Mars with dramatically reduced travel times and robotic science missions to the far reaches of our solar system.”
“Jacob’s model allows us to examine the influence of parameters such as cylinder size, rotation rate, hydrogen flow rate and the level of controlled nuclear decay of uranium,” says Dr Hollingsworth, co-author of the paper titled “One-Dimensional Steady-State Thermal Model of the CNTP Reactor.”
“The right balance of these variables will keep the cylinder walls cooled to a survival temperature while giving us the desired level of engine thrust,” says Dr Hollingsworth. “Jacob’s Best Paper Award recognizes both his extraordinary talent as a graduate student presenter and the quality of his contribution to the field.”
Conceptually intriguing, the idea of CNTP has been around since the 1960s, but the technical challenges involved have kept it off the drawing board, says Dr Thomas.
Uranium has a high melting point, so it’s a fine line between an ultra-high performance rocket engine and a radioactive hot mess, according to Dr Thomas.
The UAH team is trying to walk that line, and Keese’s research has helped the effort, he says.
“Jacob’s work on heat transfer between cold hydrogen gas and very hot liquid uranium is fundamental to establishing the technical viability of this high-performance rocket engine concept,” says Dr. Thomas.
Keese says he was deeply honored when his name was announced for the award at the conference.
“I had been blown away by the presentations at the conference and had no expectation of receiving the award for best student paper,” he says. “I also felt grateful to have had the opportunity to work on such an ambitious and interesting project.”