Measuring range adjustable and temperature insensitive fiber grating flow transducer

A measuring range adjustable and temperature insensitive fiber grating flow transducer comprises a Venturi tube part (a Venturi tube and a double-pyramid speed distributor), a sensing cylinder part (a sensing cylinder, an aluminum foil tube and an equi-strenth cantilever beam) and a measuring part (a fiber coupler, a light source and a photo-detector). The equi-strenth cantilever beam is respectively connected with the sensing cylinder and the aluminum foil tube, double fiber gratings are stuck on the upper and lower surfaces of the equi-strenth cantilever beam and connected with the measure part via fibers. The Venturi tube is provided with at least three holes, wherein one hole locates outside the corresponding area of double pyramids and is communicated with the outer portion of the aluminum foil tube, the other two holes is communicated with the inner portion of the aluminum foil tube through a control switch, thus realizing measurement of flow velocities of different flow velocity sections by using the s