The piston tunnel achieves engine representative Reynolds and Mach numbers during a flow pulse of about 0.5 seconds. The rotor spins at 9500rpm and thin film gauge instrumentation enables measurements of heat transfer on the blades, vanes and end walls. On shaft torque measurements and high resolution total pressure, velocity and temperature surveys are used to measure stage efficiency. The vanes and blades can be cooled by air or foreign gas (to achieve engine density ratio).
The OTRF has been updated to include a temperature distortion representative of rich burn.