Plasma Jet Engines Can One Day Become Commercially Viable
Plasma jet engines will, one day soon, become the main form of propelling ourselves through the air. Scientists are now on the verge of designing such plasma jet engines that can take off from the ground and reach the edge of space using only air and electricity.
In a traditional jet engine, thrust is generated by combining jet fuel with compressed air and then ignite it. By burning this mixture, it begins expanding rapidly and it’s then blasted out the back end, thus propelling the plane forward.
By comparison, plasma jet engines work by making use of electricity to generate electromagnetic fields. These compress and excite the air and turn it into plasma, similar to what you would find in a fusion reactor or a star. These engines have mostly been in testing phases and mostly on the drawing boards, with their main purpose being focused on propelling satellites while in outer space.
A team of researchers from the Technical University of Berlin, lead by Berkant Göksel are now developing ways to adapt these plasma jet engines to commercial planes.
“We want to develop a system that can operate above an altitude of 30 kilometres where standard jet engines cannot go,” he says.
The problem with these types of engines was to make them work in a denser atmosphere that we find here close to the planet’s surface. These plasma jet engines are usually designed to work in a vacuum or in a low-pressure atmosphere. The German team, however, was able to successfully test one such engine at one atmosphere.
“We are the first to produce fast and powerful plasma jets at ground level,” says Göksel. “These jets of plasma can reach speeds of up to 20 kilometres a second.”
To make it work, they used a pulse detonation system on the plasma thruster. It is, in fact, the first time someone attempted this. Jason Cassibry at the University of Alabama in Huntsville said that “It could greatly extend the range of any aircraft and lower the operational cost.”
There are some setbacks here still and it will be quite some time before plasma jet engines will become commercially viable. For starters, the team tested a mini thruster, only 80 millimetres long, and for a commercial airliner to fly it would need roughly 10,000 of them. This is why the team is first looking to implementing them on smaller aircraft that would need 100 to 1,000 such plasma engines.
The biggest impediment here, however, is the lack of any lightweight batteries.
“An array of thrusters would require a small electrical power plant, which would be impossible to mount on an aircraft with today’s technology,” says Dan Lev from the Technion-Israel Institute of Technology. This is also the reason for why they can’t just simply make these thrusters any bigger. Doing so would reduce the number needed for a plane to fly, but it will also increase the amount of power needed.
The team is hoping for a breakthrough in fusion technology, or are thinking about an alternative involving solar panels or beaming power wirelessly. In the meantime, however, they are thinking about implementing the system and creating a hybrid of both plasma engines and regular combustion ones, in order to save on fuel.