Rolls-Royce, University of Virginia engineers partner to boost jet engine efficiency
For a jet engine to be its most efficient, the hotter the engine, the better. This is because the higher the temperature in the combustion chamber, the less fuel the aircraft will need to consume.
For the aviation sector, achieving optimal levels of fuel-efficiency is crucial. The airline industry contributes between 2 and 3 percent of the world’s manmade carbon emissions, a figure likely to increase with the growth in demand for air travel. According to the European Commission, if global aviation were a country, it would rank among the top 10 emitters of today.
To address the problem, the International Civil Aviation Organization (ICAO) is introducing carbon offsetting in 2021. Participating airlines of the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) are to invest in activities that absorb Co2 emissions, like tree-planting, should their aircraft emit more than 2020 levels on certain routes.
But for the sector players, more efficient jet engines would help in more ways than one: lowering emissions and saving millions of dollars on fuel to boot.
Engineers in the space have over the past decade been working feverishly to break ground on new designs to make this possible. One crucial area of research is heat transfer technology.
Scientists at the University of Virginia’s (UVA) School of Engineering are now at the forefront of developing a solution to make the world’s jet engines ultra-efficient – by creating thermoelectric materials capable of harnessing excess energy.
Today’s commercial jet engines reach temperatures as high as 1,700 degrees Celcius, thanks to thermal barrier coatings that line the inside of the combustion chamber. Without these materials, temperatures would only reach 1,150 degrees Celcius, the point where the nickel superalloys used for the engines approach melting point.
For Professor Patrick Hopkins, that temperature change, allowed by the coating, has great potential.
“We soon discovered that, if we produced a coating that could not only survive in the hot environment but also produce current, we could harvest electricity that is then used to support the aircraft,” said Hopkins, who is also the director of Ph.D. studies in the Department of Mechanical and Aerospace Engineering at UVA.
“The efficiencies that come from harvesting even an incremental amount of energy can lead to millions of dollars in savings for our airline industry.”
Hopkins is the university’s lead on the endeavor, conducted in collaboration with Rolls-Royce, one of the world’s largest manufacturers of jet engines. UVA is part of Rolls-Royce’s global network of 31 University Technology Centres, through which the firm partners with leading academic researchers to tackle a wide range of engineering disciplines from combustion and aerodynamics to noise and manufacturing technology.
According to Rolls-Royce: “This consistent strategy of developing long-term relationships with universities has provided us with close contact to world-class academic institutions and given us access to a wealth of talent and creativity to help protect our capability into the future.”
For the UVA partnership, Hopkins has teamed up with Dr. Ann Bolcavage, a Rolls-Royce Engineering Associate Fellow in Coating Materials to work on advancing his idea. The team has also secured a US$300,000 grant from the National Science Foundation’s Grant Opportunities for Academic Liaison with Industry (GOALI) program to develop their product.
The program focuses on promoting partnerships like this one to enable technological breakthroughs and address the needs of wider society. These grants allow companies to explore potentially world-changing ideas they may not otherwise pursue, by tapping the expertise of academic research powerhouses like UVA’s School of Engineering.
“The advantage of our relationship with Rolls-Royce is that it is enabling me to bring in new graduate students and to expand the menu of activities we are pursuing in my lab,” Hopkins says.
“We are now their thermal transport people.”
In their work, Hopkins and Bolcavage will be exploring thermal barrier coatings in greater detail.
They hope to design a material with poor thermal conductivity that would be able to create this reserve of energy from the combustion, as well as one that is less expensive to produce – adding to further savings for the aviation industry.