Author:
madcows
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Date:
8/28/2009 6:00:58 PM
Subject:
Henri Coanda is totally awesome....
For several years now, I've had this idea that I've been toying with in my head, primarily based on the premise of the Coanda effect. The gist of the effect, per the all knowing wikipedia is as follows: "The Coanda effect (pronounced /'kw??nd?/) is the tendency of a fluid jet to stay attached to an adjacent curved surface of a specific radius."
Another related effect is that when a small amount of high velocity fluid/gas is dispensed along the surface of a body, it will entrain a larger body of ambient gas/fluid along the same path. In a sense, this amplifies the mass of the fluid moving along the path.
There are many different things that utilize this effect for their operation. When I was a little kid, I remember this simple pool/jacuzzi "vacuum", that basically injected a stream of water (provided by a garden hose) into a silver dollar sized orifice - the relatively high velocity of the injected water was causing the surrounding water to be sucked through the tube, and into a mesh filter. Another item used extensively in industrial manufacturing is "air transvectors" and "air knives" (http://www.vortec.com/round_transvectors.php http://www.vortec.com/curtain_transvectors.php) which can be used for many different applications.
Now, I know very little about physics, but I figured that an increase in the mass flow of air adds to the net thrust. To verify this point, I bought one of the round types (https://secure.vortec.com/store_products.php?catID=62) off ebay. I brought it over to a friend's shop, and hooked it up to the compressor. At first, I covered the mass air inlet with duct tape to see how much thrust was being generated strictly from the compressed air source, and dangled it with about a two feet worth of hose to see if it moves - it hardly did. I then repeated the same, hardly scientific test, but this time, with the tape removed. However, the HUGE increase in airflow was substantial enough to hold the device at nearly a 45 degree angle from vertical (and the piece is pretty damn heavy - cast and machined aluminum)!
So, what's my point? These things are highly efficient, in that they're able to provide a lot more energy in mass flow of a fluid in relation to their inputted energy. This effect can be put to great use in the form of thrust for propulsion - potentially in aircraft. In fact, Henri Coanda had patented such propulsion for an automobile a long time ago.
This little bit of proof to me has brought me a step closer to one day materializing my idea. You're not still reading this, are you?
