Engineers at RMIT are 3D-printing hypersonic aircraft parts. 

The researchers say their ultra-efficient 3D-printed catalysts could help solve the challenge of overheating in hypersonic aircraft and offer a revolutionary solution to thermal management across many industries.

Recent lab demonstrations have shown that 3D-printed catalysts could potentially be used to power hypersonic flight while simultaneously cooling the system.

The research is published in the Royal Society of Chemistry journal, Chemical Communications.

Only a few experimental planes have reached hypersonic speed (defined as above Mach 5 - over 6,100km an hour or 1.7km per second).

In theory, a hypersonic aircraft could travel from London to Sydney in four hours but many challenges remain in the development of hypersonic air travel, such as the extreme heat levels.

Lead researcher Dr Selvakannan Periasamy says the work tackles one of the biggest challenges in the development of hypersonic aircraft: controlling the incredible heat that builds up when planes fly at more than five times the speed of sound.

“Our lab tests show the 3D-printed catalysts we’ve developed have great promise for fuelling the future of hypersonic flight,” Dr Periasamy said.

“Powerful and efficient, they offer an exciting potential solution for thermal management in aviation - and beyond.

“With further development, we hope this new generation of ultra-efficient 3D printed catalysts could be used to transform any industrial process where overheating is an ever-present challenge.”

First author and PhD researcher Roxanne Hubesch said using fuel as a coolant is one of the most promising experimental approaches to the overheating problem.

“Fuels that can absorb heat while powering an aircraft are a key focus for scientists, but this idea relies on heat-consuming chemical reactions that need highly efficient catalysts,” Hubesch said.

“Additionally, the heat exchangers where the fuel comes in contact with the catalysts must be as small as possible, because of the tight volume and weight constraints in hypersonic aircraft.”

To make the new catalysts, the team 3D-printed tiny heat exchangers made of metal alloys and coated them with synthetic minerals known as zeolites.

They replicated at lab scale the extreme temperatures and pressures experienced by the fuel at hypersonic speeds, to test the functionality of their design.

When the 3D printed structures heat up, some of the metal moves into the zeolite framework– a process crucial to the unprecedented efficiency of the new catalysts.

“Our 3D printed catalysts are like miniature chemical reactors and what makes them so incredibly effective is that mix of metal and synthetic minerals,” Hubesch said.

“It’s an exciting new direction for catalysis, but we need more research to fully understand this process and identify the best combination of metal alloys for the greatest impact.”

The research team is based at RMIT’s Centre for Advanced Materials and Industrial Chemistry (CAMIC), whose director Professor Suresh Bhargava says the trillion-dollar chemical industry is largely based on old catalytic technology.

“This third generation of catalysis can be linked with 3D-printing to create new complex designs that were previously not possible,” Dr Bhargava said.

“Our new 3D-printed catalysts represent a radical new approach that has real potential to revolutionise the future of catalysis around the world.”