Abstract: A vortex flowmeter which is capable of measuring flow speed and flow rate both rapidly and precisely. The vortex flowmeter is composed of a ring-type bluff body situated in a pipe as a vortex shedder. The ring is bevelled at an acute angle at the inner and outer edges of the ring and the vortex shedding frequencies generated by the ring can be transformed to flow speeds and flow rates. The geometrical parameters G/W and D/W of the ring are G/W=0.50 to 0.53 and D/W=5.03 to 10.63, where G denotes the gap width between the outer edge of the ring and the pipe wall, W denotes the width of the ring, and D denotes the mean diameter of the ring. After these vortex shedding frequencies are nondimensionalized, they show a relationship with the Reynolds Numbers. The optimal streamwise location for installation of a pressure sensor is in the region of X/W=2.25 to 2.84, where X denotes the axial distance from the leading surface of the ring frontal surface.

Abstract: An axisymmetric bluff body is proposed for a vortex flowmeter as the vortex shedder. It is found that vortex shedding frequencies measured can be nondimensionalized into a linear relation with the Reynolds number for area blockage ratios of circular disks up to 29.2%. Vortex shedding frequency can be clearly sensed by a pressure transducer installed on the pipe wall in the neighborhood of the maximum pressure fluctuation being measured. This suggests a feasible design that the sensor of a vortex flowmeter can be removed from the flow field or changed easily.