The BOOSTER facility is a 1/30-scale modular, axisymmetric, cold-flow representation of the Ariane 5 solid rocket motors. It provides exact geometric and Mach number scaling of the full-scale motor when 50% of the propellant is burnt. It consists of a 76 mm internal diameter cylindrical test section made of porous cylinders, an inhibitor and a submerged nozzle. Cold air is injected radially through the porous cylinders at a rate up to 1 kg/s to simulate the hot combustion gas. A nozzle using a moveable needle to vary the sonic throat allows a continuous variation of the flow velocity through the porous cylinders from 0.3 m/s to 8 m/s, which covers the Mach number range. A wide range of geometrical and flow parameter variation can be accommodated in the facility.
The facility is used to investigate the aeroacoustic instabilities that occur in the rocket chamber and lead to undesirable pressure and thrust oscillations. Many different nozzle geometries have been tested to evaluate the influence of the nozzle on pressure oscillation levels. Passive control of the aeroacoustic instabilities and flow structure coupling are also studied.