Laminar Flow Compared to Turbulent Flow

turbulent vs laminar

Fluid mechanics is the field that studies the properties of fluids in various states.  There are two main areas; fluid statics and fluid dynamics.  Fluid dynamics studies the forces on a fluid, either as a liquid or a gas, during motion.  Osborne Reynolds, an Irish innovator, popularized this dynamic with a dimensionless number, Re. This number determines the state in which the fluid is moving; either laminar flow, transitional flow, or turbulent flow.  Equation 1 below shows the relationship between the inertial forces of the fluid as compared to the viscous forces.

Equation 1:  Re = V * Dh/u

Re – Reynolds Number (no dimensions)

V – Velocity (feet/sec or meters/sec)

Dh – hydraulic diameter (feet or meters)

u – Kinematic Viscosity (feet^2/sec or meter^2/sec)

The value of Re will mark the region in which the fluid (liquid or gas) is moving.  If the Reynolds number, Re, is below 2300, then it is considered to be laminar (streamline and predictable).  If Re is greater than 4000, then it is considered to be turbulent (chaotic and violent).  The area between these two numbers is the transitional area where you can have eddy currents and some non-linear velocities.  To better show the differences between each state, I have a picture below that shows water flowing from a drain pipe into a channel.  The water is loud and disorderly; traveling in different directions, even upstream.  With the high velocity of water coming out of the drain pipe, the inertial forces are greater than the viscous forces of the water.  This indicates turbulent flow with a Reynolds number larger than 4000.  As the water flows into the mouth of the river, the waves transform from a disorderly mess into a more uniform stream.  This is the transitional region.  A bit further downstream, the stream becomes calm and quiet, flowing in the same direction.  This is laminar flow.  Air is also a fluid, and it will behave in a similar way depending on the Reynolds number.

Turbulent to Laminar Water

Why is this important to know?  In certain applications, one state may be better suited than the other.  For mixing, suspension and heat transfer; turbulent flows are better.  But, when it comes to effective blowing, lower pressure drops and reduced noise levels; laminar flows are better.  In many compressed air applications, the laminar region is the best method to generate a strong force efficiently and quietly.  EXAIR offers a large line of products, including the Super Air Knives, Super Air Amplifiers and Super Air Nozzles that utilizes that laminar flow for compressed air applications.  If you would like to discuss further how laminar flows could benefit your process, an EXAIR Application Engineer will be happy to help you.

John Ball
Application Engineer
Email: johnball@exair.com

Twitter: @EXAIR_jb

How Can You Benefit from EXAIR’s Efficiency Lab?

How many times have you purchased a new product and worried if it was the right choice? Well EXAIR can provide that confidence using our calibrated testing equipment to compare your current product to an EXAIR product, in our Efficiency Lab. Whenever I needed a new process or product I would spend countless hours researching how will this benefit me, my employer or my customer? Research is not only time consuming but also very costly.

EXAIR believes in their product so much that we offer an Efficiency Lab where we will test your production product and help show that our products will not only work for you, but also show that they can save money, as well as make your work environment a safer place.

EXAIR has provided performance values (force, noise, air consumption, ROI) for many of our products. We make purchasing from EXAIR fun because you know in advance that our products will meet or exceed your expectations. Further backing up our commitment with the Efficiency Lab we offer an 30 Day Unconditional Guarantee. EXAIR believes in our products and want to make your purchase a risk free process.

We can test the performance of your current product to EXAIRs Intelligent Compressed Air products for air consumption, force, noise levels… and provide a comprehensive report of our analysis, including simple ROI.  

What does our Efficiency Lab cost? EXAIR believes in our products so much, that this is a free service to our customers. Simply call and talk to one of our Application Engineers at 800.903.9247 or you can send an email to lab@exair.com or visit www.exair.com and talk on our live help. If you feel we can help with a comparison them simply send your product(s) freight prepaid to EXAIR Corporation attention to our Efficiency Lab. All trials will be on a confidential basis unless you provide permission to share.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK

Video Blog: Filter/Separator and Pressure Regulator Mounting and Coupling Kit Installation

Using EXAIR mounting and coupling kits you can assemble EXAIR Filters and Regulators into one plug and play assembly. Follow along with the video posted below to complete this task!

If you need a deeper understanding about how EXAIR’s products can be applied and help your process or product, feel free to contact us and we will do our best to give you a clear understanding of the benefits when using our engineered compressed air products. We can also explain proper implementation of accessory items such as compressed air filters and regulators.

Jordan Shouse
Application Engineer

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Save Compressed Air Energy with Pressure Regulators

Why should you consider a Pressure Regulator when designing your compressed air system? As many know, our products and those of other  product manufacturers have a certain set of specifications regarding performance at stated input pressures. But what if your application doesn’t require that “full, rated performance”? Maybe instead of needing two pounds of force, you only need one pound? Sometimes more force does not produce the desired result for an application. By that, I mean you cause damage to the target or other surrounding items in the application. Or, perhaps blowing too hard (or vacuuming too hard in the case of a Line Vac or E-vac) might cause the vessel or the material you are picking up to collapse or deform (due to too much power).

Regulators catalog
EXAIR offers a range of Pressure Regulators capable of handling air flow of up to 700 SCFM.

There is also the concern about using more energy than one really needs to in order to achieve the desired effect in an application. In other words, if you can achieve your goals with only 40 PSIG, then why would you ever use 80 PSIG to accomplish the goal? By reducing your compressed air from 80 down to 40 PSIG, you can easily reduce the air consumption of the “engineered” solution by another 40% or more.  Once you have installed engineered air nozzles to reduce compressed air on blow off applications, a pressure regulator can fine tune the pressure to save even more energy.

Regulator Internal
Regulator Internals

Then there is the issue of taking advantage of the pressure differential (from 80 down to 40 PSIG) that creates a little bit more air volume capacity. At 80 PSIG, your compressed air to free air volume ratio is 6.4:1. At 40 PSIG, it is only 3.7:1. The net effect is you effectively have an overall larger volume of air you can use for other applications in your facility. By reducing compressed air pressure of your demand applications, you may be able to reduce over all compressor discharge pressure. Reducing compressor discharge pressure by 2 PSIG also reduces required input power by 1 percent – so keep your pressure as low as possible!

Regulating pressure is definitely warranted given the benefits that compliment the operation of the core EXAIR products.

If you need a deeper understanding about how EXAIR’s products can help your application, feel free to contact us and we will do our best to give you a clear understanding of all the benefits that can be had by our products’ use as well as proper implementation of accessory items such as compressed air filters and regulators.

Jordan Shouse
Application Engineer

Send me an email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS