A team of scientists at the Stanford Predictive Science Academic Alliance Program (PSAAP) are modeling the fuel and airflow of a scramjet engine. The work is part of a $20 million project that researchers hope will lead to a major breakthrough in hypersonic flight. Eureka magazine covered the PSAAP’s progress.
Hypersonic flight occurs at extremely fast speeds (roughly Mach 5 and above) and NASA has been testing vehicles to travel at these speeds since 2001. The X-43A supersonic combustion ramjet (scramjet) is a small aircraft that utilizes atmospheric air to help fuel its flight. Previous tests have clocked the hypersonic craft at Mach 9.6 or roughly 7,000 mph, which earned it a spot in the Guinness World Records book.
Amazing as the speed records may be, the X-43A’s scramjet engine suffers from a problem called ‘unstart.’ Parviz Moin, a professor at Stanford’s school of engineering explained the issue:
“If you put too much fuel in the engine when you try to start it, you get a phenomenon called thermal choking, where shock waves propagate back through the engine. Essentially, the engine doesn’t get enough oxygen and it dies. It’s like trying to light a match in a hurricane.”
This is the focus of PSAAP’s research and they plan to make design changes based on results from supercomputing models. The project is also receiving help from Stanford’s computer science and mathematics, aeronautics and astronautics, as well as engineering departments.
Moin recognized that a multi-departmental effort was required to model scramjet behavior. He says the mechanical and aeronautical engineers, who understand the problem, need to get together with the computer scientists so that more sophisticated simulations can be built. That will be especially crucial as supercomputers move into the exaflops realm.
With that in mind, the PSAAP team developed a new computer language, know as LISZT, for processing complex simulations using a large amount of compute cores. The tool is designed for exascale computing, enabling scientists to study combustion, turbulence, fluid dynamics as well as any other mathematically complex simulations at scale.
In the video below, LISZT was used to demonstrate exhaust temperature fluctuations from a passenger jet engine. The simulation was accomplished over four days, utilizing 160,000 cores.