FLUID FLOW MEASUREMENT

摘要

FLUID FLOW MEASUREMENT An instrument for measuring simultaneously the flow rate and density of a moving fluid includes means for measuring the frequency and amplitude of vortices shed by interaction of the fluid with a bluff body. Typically the sensing means includes an optical fibre movable in response to pressure changes in the fluid. Computation of the mass flow rate of the fluid can be effected. In one embodiment a light signal from a transmitter (41) is modulated via a sensor (42) and is then fed via a detector (45) and A to D converter (46) to a microprocessor (47) where demodulation and computation of mass flow rate is effected. The microprocessor also provides negative feedback to maintain the output level of the transmitter substantially constant.