Henri Coanda: June 7, 1886 – November 25, 1972

Compressed air flows through the inlet (1) to the Standard Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.

How did a past inventor help generate efficient compressed air products for EXAIR?  In the early 20th century, Henri Coanda who was a Romanian aeronautical engineer built an experimental Coanda-1910 airplane.  There are some debates if the airplane actually flew, but he invented a curved surface for a wing to generate a Coanda effect. The Coanda effect is the “tendency of a fluid jet to stay attached to a convex surface”1.   Thus, a moving stream of fluid will follow the curvature of the surface rather than continuing to travel in a straight line.  The Wright Brothers who flew the first airplane in the state where EXAIR is located, Ohio, used the Coanda effect to create lift.  With a curved profile, the air will adhere to the surface, causing a low pressure which makes the airplane fly.

EXAIR also uses this Coanda profile to make some of our Intelligent Compressed Air Products™.  Like an airplane wing, our curved surface will create a low pressure.  How does this help?  Well, higher pressure will always travel to lower pressure.  Instead of lift, we use the low air pressure to entrain ambient air.  This ratio of entrained air to compressed air is what we call the amplification ratio.  The higher the amplification ratio, the higher the efficiency for a blowing device. Two main compressed air products that EXAIR manufactures use this type of profile; Air Knives and Air Amplifiers.  I will cover both below. 

The Air Knives that use the Coanda profile blows air along the length of the knife at a 90o angle from the exit.  We offer two types; the Standard Air Knife and the Full Flow Air Knife.  The Standard Air Knives are made in Aluminum or Stainless Steel with blowing widths up to 48” (1219mm).  The inlet ports are at each end; so, the overall length is 1” (25.4mm) longer than the blowing length.  The Full Flow Air Knives have a port, or ports, on the backside.  Like the name states, the air blows out the entire length of the air knife.  The maximum length is 36” (914mm).  Both types use the Coanda profile to generate a low pressure as the air exits the gap and “hugs” the curve (reference photo above).  This low pressure draws ambient air into the air stream at a 30:1 amplification ratio for both the Standard Air Knife and Full Flow Air Knife.  So, for every one part of compressed air, we entrain 30 parts of ambient air.  Besides efficiency, it also adds mass to the air stream for a hard-hitting force.  With the engineered profile, the airstream is laminar which gives a consistent force across the entire length and makes them quiet.  Not only will they save you money by using less compressed air, but they are also OSHA safe.    

Super Air Amplifier – flow region

The Air Amplifiers use the Coanda profile in a circular form to pull in large amounts of free surrounding air.  The Coanda effect is able to generate a low pressure in the center to blow air for cooling, cleaning or removing welding smoke and debris efficiently and quietly.  The Air Knives above will blow a flat stream of air while the Air Amplifiers will blow a conical air stream.  They can reach amplification ratios up to 25:1. The Super Air Amplifiers use a patented shim to increase efficiency.  Unlike fans, they blow a laminar air stream for quick cooling.  They do not have any moving parts or motors to wear, so they are very quiet.  EXAIR manufactures five different sizes from ¾” (19mm) to 8” (203mm).  The Adjustable Air Amplifiers have a plug that can be adjusted to control the blowing from a breeze to a blast.  For cleaning surfaces, this is a nice feature to “dial” in the correct amount of blowing force.  We also manufacture five different sizes ranging from ¾” (19mm) to 4” (102mm).  Both types can be ducted to remove debris, heat or smoke. 

Utilizing the Coanda effect allows for massive compressed air savings. Whether it is a flat or round air stream, EXAIR can do this with high amplification ratios.  If you would like to discuss further how our Air Knives or Air Amplifiers can help you in your application, please contact us. An Application Engineer will be happy to help you replace your inefficient blowing devices.  History has given us a way to increase efficiency for blowing compressed air.  Thank you, Henry Coanda. 

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

1note – Wikipedia – Coanda effect

What Is A Coanda Profile?

The big thing that sets engineered products like EXAIR Intelligent Compressed Air Products apart from other devices is the engineering that goes into their design.  Several principles of fluidics are key to those designs:

The one I wanted to discuss today, though, is the Coanda Effect, what it means for our engineered compressed air products, and what they can do for you:

The Coanda effect is named after Henri Coandă, who was the first to use the phenomenon in a practical application…in his case, aircraft design.  He described it as “the tendency of a jet of fluid emerging from an orifice to follow an adjacent flat or curved surface and to entrain fluid from the surroundings so that a region of lower pressure develops.”  Put simply, if fluid flows past a solid object, it keeps flowing along that surface (even through curves or bends) and pulls surrounding fluid into its flow.  Here’s a demonstration, using an EXAIR Super Air Amplifier and a plastic ball:

What’s interesting here is that the Super Air Amplifier is not only DEMONSTRATING the Coanda effect, it’s also USING it:

Air Amplifiers use the Coanda Effect to generate high flow with low consumption.

EXAIR Standard and Full Flow Air Knives also have Coanda profiles that the primary (compressed air) flow follows, and uses, to entrain “free” air from the surrounding environment:

Compressed air flows through the inlet (1) to the Standard Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.

EXAIR Air Wipes can be thought of as “circular Air Knives” – instead of a Coanda profile along the length of an Air Knife, an Air Wipe’s Coanda profile is on the ring of the Air Wipe, which entrains surrounding air into a 360° ring of converging air flow:

Air Wipe – How it works

So that’s the science incorporated in the design of our products.  But what does it mean to the user?

  • Efficiency.  Pulling in a tremendous amount of “free” air from the surrounding environment means minimal consumption of compressed air, while still getting a hard hitting, high velocity air flow.
  • Sound reduction.  This air entrainment also creates a boundary layer in the air flow, resulting in a much quieter air flow than you get from a simple open-end blow off.

EXAIR Corporation is committed to helping you get the most out of your compressed air system, and thanks to Mr. Coandă, that includes reducing your compressed air consumption and noise levels.  If you’d like to find out more, give me a call.

Russ Bowman, CCASS

 

 

 

Application Engineer
EXAIR Corporation
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Air Amplifiers – Air Pressure or Air Flow Volume

When talking about Air Amplifiers there are two (2) kinds when considering what best fits your needs. An amplifier that is used to increase pressure above your compressor’s ability are also known as air boosters. These boosters are sometimes needed for specific processes which demand much higher pressures. Amplifiers that increases the volume flow rate of your compressed air or nitrogen are the type of amplifier that EXAIR manufactures. 

EXAIR’s Super Air Amplifiers will increase the volume of air on to a target or being circulated in an environment. EXAIR’s Air Amplifiers use the Coanda effect pulling in large volumes of surrounding air to produce high volume, high velocity outlet flows up to 25 times their consumption rate.

Air Amplifiers have no moving parts and are basically maintenance free. EXAIR’s amplifiers operate on a source of clean compressed air and do not use electricity. The outlet flows are easily adjusted by opening or closing the air gap. By regulating the supply pressure you can tune in your outlet flow to meet your specific needs. Vacuum and discharge ends of the Air Amplifier can be ducted, making them ideal for drawing fresh air from another area or for moving smoke and fumes away.

Super Air Amplifier Family

EXAIR has 5 standard sized Air Amplifiers ranging from 3/4″ (19mm) to 8″ (203mm) plus an Adjustable Air Amplifier . If you have a specific application EXAIR can manufacture Air Amplifiers to fit your application. If you have a project and think EXAIR’s Air Amplifier or any of our Intelligent Compressed Air Products please contact me or any of our qualified Application Engineers to discuss your project.

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

Henri Coanda: Founder of The Coanda Effect (1886-1972)

EXAIR uses the Coanda effect in many of our products. Henri Coanda is an important figure in the world of fluid dynamics and aerodynamics.

Henri Coanda was a prominent Romanian Inventor and aerodynamics pioneer is known for the creation of the Coanda-1910 experimental plane as well as discovering the Coanda effect. On June 7, 1886 Henri was born in Bucharest Romania to General Constantin Coanda and Aida Danet. In 1899 Henri’s father who desired him to have a military career had him transfer to a Military High School for additional years of schooling, where he graduated with the rank of Sergeant Major. Continuing his studies, he went on to technical school back in Bucharest for Artillery, Military, and Naval Engineering. In 1904 he was sent to an artillery regiment in Germany where he would enroll in Technische Hochshule. Henri did not give up on studying and in 1907 went to Montefiore Institute in Liege, Belgium, where he met Gianni Caproni.

In 1910 Henri and Gianni began a partnership to construct an experimental aircraft which was later called the Coanda-1910. The Coanda-1910 was unlike any other aircraft of its time as it had no propeller; instead it sported an oddly shaped front end with built-in rotary blades arranged in a swirl pattern. These blades were driven by an internal turbine screw that would suck air in through the turbine while exhausting the gases out of the rear, propelling the plane forward. This initial jet engine was quite impressive for the time, but sadly nobody believed it would ever fly and is believed that it never did achieve flight. Coanda is not credited with the invention of the jet engine, but his technology spurred the future of aviation into the future.

During World War 2 Henri spent his time developing the turbo-propeller drive system from his 1910 Biplane. After World War 2 had ended Henri began furthering his research on the Coanda Effect which would become the basis for several investigations into entrained and augmented flow of fluids. Later on in 1969 Henri would spend the last of his days in Romania serving as Director of the Institute for Scientific and Technical Creation. Coanda died on November 25, 1972 in his home town of Bucharest.

Here at EXAIR we have taken Henri Coanda’s, Coanda Effect and applied it to a number of our products to help amplify total airflow and save on compressed air.  The most notable product lines are our Air Amplifiers, Air Nozzles, and Air Knives – which are some of the most efficient products of their kind. These products can help lower your compressed air demand. 

If you have any questions about compressed air systems or want more information on any of EXAIR’s products, give us a call, we have a team of Application Engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
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