Australian National University Phd student Alan Griffiths, a graduate of the University of Tasmania, has helped to develop a new laser based technique to test engine performance in Scramjets.
Scramjets are hypersonic jet engines; Scramjet is an acronym for ‘supersonic combustion ramjet.’
The new laser research demonstrates the importance of the Australian contribution to scramjet development ahead of planned experimental flights at Woomera later this year.
NASA’s X-43A was the first successfully flown Scramjet on November 16, 2004 at a world record speed of about Mach 10 or 10 times the speed of sound.
However, Australian research continues to be vital in helping to make hypersonic aircraft a reality.
University of Queensland hypersonics expert Professor Allan Paull emphasised the importance of Australia’s role in Scramjet research.
“Australia has contributed to the hypervelocity development of Scramjets. This is the development of these engines above Mach 8. It has also contributed by developing cost effective flight testing approaches,” Professor Paull said.
Professor Paull believes people should be interested in Scramjets because they will “affect their and their children’s lives.”
Hypersonic flight has the potential to totally change aviation, but for now Scramjet engines are just experimental.
There has been only one example of a Scramjet-powered vehicle actually flying under its own power, the X-43A.
Yet the implications of the research are enormous.
The US Military has its sights set on Scramjet technology.
Implications for space technology
“Because of the money the military has, they’ll probably get their hands on the technology first,” says Mr Griffiths.
There are also implications for space technology.
“If you got up to Mach 25 you can get into orbit. At the moment the only way to get into orbit is to use a rocket engine. With a rocket engine you’ve got to carry your fuel and your oxygen on board…well over half the mass is oxygen and that’s huge expense,” says Mr Griffiths.
Thus Scramjets would be a much more efficient way of getting a vehicle into orbit.
“With a Scramjet engine you only have to carry the fuel and you can scoop the oxygen out of the atmosphere… you could launch things into space at a much lower cost,” Mr Griffiths said.
Passenger travel could also be changed forever.
“If you decided to put passengers in there you could make a vehicle that travelled from Sydney to London in about forty five minutes,” says Mr Griffiths.
“For my work we take a model Scramjet engine and put it inside a test facility called a free-piston shock tunnel. This generates the high speed flow of air that simulates the flow that you’d have going past the vehicle that’s in flight,” Mr Griffiths said.
Mr Griffith’s laser technique enables Scientists to study scramjet engine performance in a shock tunnel by measuring water vapour and temperature.
“Water vapour’s important because if you’re injecting fuel into this airstream, if it burns it produces water vapour, so it’s measuring the efficiency of the engine.”
The research could also make it possible to place compact diagnostic equipment in a Scramjet engine.
“A pilot could be sitting in the cockpit and looking at one of the gauges connected up to this sensor and that would give an idea of what the engine’s doing,” said Mr Griffiths.
Mr Griffiths’ findings have proven that it is possible to use this laser technique in a Scramjet.
Jamie Rosewell is completing a degree in journalism at UTAS
