Which of the following flowmeters are affected by the flow regime in which they are operated? 

A. Coriolis mass 

B. Differential pressure

C. Positive displacement

D. Turbine

E. Ultrasonic

 

Coriolis mass flowmeters (Answer A) and positive displacement flowmeters (Answer C) operate properly in all flow regimes.

Differential pressure flowmeters (Answer B) and turbine flowmeters (Answer D) operate linearly in the turbulent flow regime but become nonlinear in the laminar and transitional flow regimes.  

Most ultrasonic flowmeters (Answer E) operate linearly in the turbulent flow regime, but some designs operate nonlinearly in the transitional and/or laminar flow regimes.   

Additional complicating factors

Operating differential pressure, turbine and ultrasonic flowmeters in the transitional flow regime can introduce significant errors, so special calibration and linearization may be required to reduce these errors in some applications.  

Some differential pressure flowmeters are designed to operate in the laminar and transitional flow regimes.

David W. Spitzer

 

David W. Spitzer is a regular contributor to Flow Control magazine and a principal in Spitzer and Boyes LLC, which offers engineering, seminars, strategic, marketing consulting, distribution consulting and expert witness services for manufacturing and automation companies. Spitzer and Boyes is also the publisher of the Industrial Automation INSIDER. He has more than 40 years of experience and has written more than 10 books and 350 articles about flow measurement, instrumentation and process control. Spitzer may be reached at 845-623-1830 or via spitzerandboyes.com. Click on the “Products” tab to find his Consumer Guides to various flow and level measurement technologies.