ISA Interchange

Welcome to the official blog of the International Society of Automation (ISA).

This blog covers numerous topics on industrial automation such as operations & management, continuous & batch processing, connectivity, manufacturing & machine control, and Industry 4.0.

The material and information contained on this website is for general information purposes only. ISA blog posts may be authored by ISA staff and guest authors from the automation community. Views and opinions expressed by a guest author are solely their own, and do not necessarily represent those of ISA. Posts made by guest authors have been subject to peer review.

All Posts

AutoQuiz: How is the Reynolds Number Used in Flow Measurement?

 

AutoQuiz is edited by Joel Don, ISA's social media community manager.

 

This automation industry quiz question comes from the ISA Certified Control Systems Technician (CCST) program. Certified Control System Technicians calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables. Click this link for more information about the CCST program.

 

Reynolds number, a dimensionless quantity used to describe flow in a pipe, can be represented by the formula:

Re = ρ V dh / µ

This quantity is useful because it describes the ratio between which two quantities?

a) ratio of electrical charge to fluid capacitance for the fluid
b) ratio of specific gravity to heat capacity of the fluid
c) ratio of inertial forces to viscous forces on the fluid
d) ratio of frictional forces to kinetic forces on the fluid
e) none of the above

 

Answer A cannot be correct: Reynolds number does not indicate a relationship of electrical properties of fluids.

Answer B cannot be correct: Reynolds number does not give a relation to the thermal or mass capacity properties of fluids.

Answer D is not correct. While frictional forces could be equated to viscous forces and kinetic forces could be equated to inertial forces, the ratio indicated in Answer D would be the inverse of the true relationship.

The correct answer is C, the ratio of inertial forces to viscous forces on the fluid.  The inertial forces in the numerator are given by the product of mass (density), fluid velocity, and pipe diameter.  The viscous forces on the fluid are represented by the viscosity in the denominator.

Reference: Hughes, T.A., Measurement and Control Basics, Fifth Edition.

 

About the Editor
Joel Don is the community manager for ISA and is an independent content marketing, social media and public relations consultant. Prior to his work in marketing and PR, Joel served as an editor for regional newspapers and national magazines throughout the U.S. He earned a master's degree from the Medill School at Northwestern University with a focus on science, engineering and biomedical marketing communications, and a bachelor of science degree from UC San Diego.

 

Connect with Joel
LinkedInTwitterEmail

 

 

Joel Don
Joel Don
Joel Don is an independent content marketing, social media and public relations consultant. Prior to his work in marketing and PR, Joel served as an editor for regional newspapers and national magazines throughout the U.S. He earned a master's degree from the Medill School at Northwestern University with a focus on science, engineering and biomedical marketing communications, and a bachelor of science degree from UC San Diego.

Related Posts

ISA: Growing Stronger Together for a Brighter Future

As a part of the International Society of Automation (ISA) community—I see firsthand how our Society need...
Eddie Habibi Feb 29, 2024 9:46:56 AM

Is AI the Key to Unlocking Procurement Cost Savings?

As more people experiment with using artificial intelligence (AI) for real-life use cases, many wonder if...
Emily Newton Feb 27, 2024 10:15:02 AM

My ISA Journey

My ISA journey thus far has been one ripe with growth and knowledge. I’m lucky to say it has been one of ...
Prabhu Soundarrajan Feb 22, 2024 12:12:00 PM