Technical Center

Vortex Flow meter principle

Hot:43022013-06-23 11:27:44 From: FTD Automation Instruments

 

The flow measurement of vortex flow meter is according to the principle of Karman Vortices. When a bluff body is placed vertically in pipe, as the fluid flows around the bluff body, regular vortices columns will be generated alternately on each side of the bluff body (shown as Fig.1), these eddies known as “Karman Vortices”. The resistance part shedding the vortices is named “bluff body”. The frequency of the vortices shedding is related to the velocity of the fluid. Expressed by formula as below:

Thereinto:

f----frequency of Karman Vortices shedding

Sr----Strouhal number

U---- average velocity in the pipe

d----width of bluff body inflow face

m----the ratio of the flow-area sum on both side and measuring pipe section area

U1----average velocity on two sides of bluff body

Thereinto: D----inside diameter of pipe

d----width of bluff body inflow face (unit: mm)

Fig.1

Strouhal number is related with the shape of bluff body and Reynolds number (shown as chart 2). From the chart, Sr is constant basically when the range of Reynolds number is

Principle of Vortex Flow meter

FTD Automation Instruments Limited - Field Instruments © 2013 •   Support by 外贸网站建设
LiveZilla Live Chat Software