Laser Doppler Velocimeter System for Use on Gas Turbines

A laser Doppler velocimeter (LDV) system has been developed for use on practical gas-turbine engines. The system has been used to measure inlet and exhaust velocities on an F-100 EMD engine from an F-15 airplane (see Figure 1). To perform this work successfully, it was necessary to develop several novel subsystems, including a rugged LDV transceiver, a high-performance frequency-domain signal processor, and equipment for adding seed particles to the inlet and exhaust flows. In addition, it was necessary to provide for remote control of the system from a blockhouse at a distance of 30 m from the engine.