Rolls-Royce is to work with Purdue University in Indiana, USA, to research propulsion technologies for future aircraft capable of speeds of up to Mach 7. The R-R University Technology Centre (UTC) will study the use of fuel to cool engine turbo machinery and the effects of fatigue on engine life.

Stephen Heister, professor at Purdue's School of Aeronautics and Astronautics, says that using fuel as a heat sink requires detailed knowledge of the high-temperature properties of jet fuel. "We hope to use fuel to cool the air going into the turbine, as well as for turbine blade cooling," says Heister. "But we need to understand the fuel's physical and chemical properties in high temperature and pressure environments," he adds.

Heister says R-R has already demonstrated fuel properties at temperatures up to 200¡C (400¡F), but Purdue now wants to investigate properties up to 430¡C. "Potential problems include chemical changes in the fuel affecting its behaviour in the combustor, and fuel coking causing carbon deposits on fuel line walls, which could impede heat transfer and lead to burning of components," says Heister. Researchers will also study suitable fuel injectors for the combustion of high-pressure supercritical fuel.

Heister says the Pratt & Whitney J58 turbojet, developed for the Lockheed SR-71 Blackbird, is being used as reference technology for Purdue's high-Mach engines, for aircraft with speeds of up to 4,300kt (8,000km/h).

Source: Flight International