Rotating vortex flow meter
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What about spiral vortex flowmeters? Aren’t they less effective for measuring gases compared to vortex flowmeters, even though they have a wide range?
Vortex flow meter: A flow meter based on the Karman vortex street principle; it is a type of instrument that relies on fluid oscillations. When fluid passes through a non-streamlined cylinder (usually with an approximately triangular cross-section), alternating vortices are generated on either side of the cylinder. When a vortex forms on one side, it suppresses the formation of vortices on the other side, causing those vortices to separate from the cylinder and move along with the fluid. At the same time, new vortices form on the side where the original vortex was present, thereby suppressing vortex separation on that side. This process repeats alternately on both sides of the cylinder. The vortices on these two sides are arranged similar to objects on either side of a road, which is why this phenomenon is also known as a vortex street. Once the dimensions of the cylinder are fixed, the separation frequency of the vortex street depends only on the flow velocity of the fluid, and it varies linearly with this velocity within a certain range. This separation frequency is detected and processed by piezoelectric sensors, resulting in a flow rate signal being output. Vortex flowmeter: A fixed turbine vortex generator is installed in the inlet pipe of the flowmeter; as the fluid passes through this generator, it begins to rotate around the axis of the pipe’s center line, forming a vortex core. This vortex core rotates along the pipe’s center line while moving forward with the fluid, and its rotation radius gradually increases. Under the effect of counterflow, a spiral-shaped secondary rotation occurs. The frequency of this secondary spiral motion is directly proportional to the flow velocity over a wide range of flow rates. This frequency is detected by piezoelectric sensors and processed to produce a flow signal. In comparison, the vortex-inflow meter has better vibration resistance than the vortex street meter; it offers higher accuracy, greater stability and reliability, as well as a wider range.