Evatt Hawkes has turned his childhood pyromania to good account – investigating fire and combustion at an elevated level of science. Now a professor of mechanical engineering at the University of NSW, he uses computational modelling to further the global understanding of combustion in renewable energy technology.
A specialist in computation and a leader in his field of combustion and propulsion, Hawkes is at the forefront of the race to decarbonise the economy and tackle the challenges of transforming transport and energy systems to work with renewables such as green hydrogen. “We’re trying to basically understand what the hell’s going on with things like hydrogen combustion and provide fundamental knowledge and tools that industry can use to reliably design engines,” he says. “That’ s our raison d’etre.”
A chemical reaction which requires a mix of fuel and air and a heat transfer, combustion can be influenced by turbulence in the flow, which stirs things up and can have a knock-on effect. Turbulent flows are yet to be fully understood, Hawkes says, and turbulent combustion adds yet another layer of complexity to already complex scenarios.
“Believe it or not, despite using combustion technologies for hundreds of years, or a million years if you consider just fires, we actually don’t understand it that well,” he says. “So we work on providing the missing understanding. There’s a lot of things we don’t get. The thing which I focus on, that we don’t understand that well, is how turbulent flows interact with combustion.”
Hawkes and his colleagues run extremely large simulations of combusting fluid on super computers. Their simulations are fundamental research; they comprise a long series of incredibly complicated calculations and they are expensive to run. It might take 20,000 CPU processor cores running for three solid weeks to complete one simulation on either of the two super computers the team uses, a machine called Gadgi at the National Computational Infrastructure in Canberra, and a new machine called Setonix (the scientific name of the quokka) at the Pawsey Super Computing Centre in Western Australia.
“Our approach is a useful scientific tool and we can learn a lot about combustion with this tool, but it’s not a tool industry can use – because it’s too expensive to run those types of simulations,” Hawkes says. “In their design process, they need a much cheaper computation and we use our very detailed ones to try to help develop those cheaper ones that industry can afford to use.”
Hawkes and his colleagues work with industry, including gas turbine manufacturer General Electric and energy solutions giant MAN. “We target our problems so that they’re relevant to the development of engines,” he says, adding experts in the field are now focused on the best ways to burn renewably-produced fuels, including carbon-free hydrogen and ammonia, in heavy-duty compression ignition engines such as those used in aviation, in ships and long-haul trucks, and in stationary gas turbines that make energy. “These fuels have very different combustion properties compared with the conventional fossil fuels we’ve been burning forever.”