Laser Doppler velocimeter applied to measurements in model of nozzleless motor

The determination of the aerodynamic field in a set-up which simulates the gas flow issued from the combustion of a propellant in a nozzleless motor is carried out by use of a laser Doppler velocimeter. The device is inserted in a rectangular vein closed on headend by a metallic plate. The outlet is shaped in a divergent configuration. The upper and the lower walls are made of homogeneous porous plates for injection of a well known air flow rate. Lateral parts are equipped of large silicate windows. The two colors laser Doppler velocimeter works in forward scattered light mode to determine the velocity field in the vertical median plane. Though gases are injected at low velocity through the porous slabs (3 m/s to 10 m/s according to the location), the velocity on the axis reaches up to 300 m/s by the exit.