Effects of Abrupt Pipe Diameter Changes on Venturi Flowmeters

Although accurate flow measurement is a requirement in many applications, flowmeters are often installed in unfavorable conditions. Any time a flowmeter is installed close to a flow disturbance, such as a pipe fitting or a valve, the installation should be investigated to ensure there will be no negative effects on the meter’s performance. This study investigated the use of computational fluid dynamics (CFD) coupled with laboratory data to determine the effects that sudden changes in pipe diameter can have on the discharge coefficients of Venturi flowmeters. The study determined how accurately CFD can match laboratory data, then used CFD to determine the distance needed between a sudden change in diameter and a Venturi flowmeter so that the meter is no longer affected by the disturbance. The results show that CFD can be an effective tool for investigating installation effects for flowmeters.