Question

***Fluid Flow***

What is the difference between using venturi meters vs orifice meters? Is there an advantage for using one over the other the two?

Answer 1

applicability of instrument to specific problem and its operation costs, its valid range are important factors in measuring inflow and outflow of fluid.

meters opearated in fluid in pipe or channel are called full bore meters.

in full bore meters - variable head meters and variable area meters are classified.

eg: venturimeter orifice meter are variable head meters,

rotameter comes under variable area meter

venturimeter

1.it is used to measure flows in large lines such as city water systems.

2.it is expensive

3. occupies considerable space

4. ratio of throat dia to pipe dia cannott be changed, so if flow rate range changes results in inaccurate pressure differences

5. causes very low head losses due to its gradual contraction and expansion design

orifice meter

1. occupies less space, simplest design

2. have higher minor loss coefficients so low coefficient of discharge(C_d) compared to C_d of venturimeter.

3.permanent head loss is more than that for venturi because of eddies fomed when jet expands below the vena contracta