Metering of Fluids at High Velocities with Vortex Shedding Flowmeters

摘要

Vortex shedding flowmeters have been designed and tested for measuring liquid andgas flows to the maximum velocities found in the ducts of the Space Shuttle Main Engines. The flow velocities found in these ducts are several times greater than found in conventional metering applications. The shedder bar was narrowed relative to conventional vortex shedding flowmeter designs to reduce the head loss introduced at the extreme flow velocities. The presence of bends in the duct near the flowmeter, while expected to degrade the meter performance, rather improved it in terms of signal quality relative to the performance in a straight duct. The performance also improved with a decrease in viscosity of the measured fluid. The signal quality obtained approached that of the modified commercial vortex shedding meters used to provide flow calibration.