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In an apparatus and method for ejecting an additive for significantly reducing the drag of a first fluid moving relative to a wall, a drag-reducing substance is conditioned by causing a second fluid, which includes the drag-reducing substance as a dispersed solid, liquid or gas, to flow through a no

In an apparatus and method for ejecting an additive for significantly reducing the drag of a first fluid moving relative to a wall, a drag-reducing substance is conditioned by causing a second fluid, which includes the drag-reducing substance as a dispersed solid, liquid or gas, to flow through a nozzle. The second fluid is then passed by a vortex chamber prior to ejection of the second fluid into the first fluid via an aperture that includes a Coanda surface on a portion thereof. Additional techniques are also disclosed which increase the effectiveness and efficiency of ejecting a drag-reducing substance into a fluid that is moving relative to a wall, and which thus enable multiple layers to be established without the undesirable disruption of the boundary layer and without the rapid diffusion of the additives across the boundary layer that occur in prior art ejection techniques.

대표청구항 ▼

1. A method of ejecting a drag-reducing substance into a first fluid in a manner that avoids disruption and "blow-off" of the first fluid and reduces the rate of diffusion of the drag-reducing substance in the first fluid to thereby increase the effectiveness of the drag-reducing substance in reduci

1. A method of ejecting a drag-reducing substance into a first fluid in a manner that avoids disruption and "blow-off" of the first fluid and reduces the rate of diffusion of the drag-reducing substance in the first fluid to thereby increase the effectiveness of the drag-reducing substance in reducing drag of the first fluid in moving relative to a wall, said method comprising the following steps, performed in the order indicated:a) conditioning the drag-reducing substance by causing a second fluid, which includes the drag-reducing substance as a dispersed solid, liquid or gas microbubble and substance mixture, to flow through a nozzle that produces an axial velocity gradient within the second fluid containing the additive as a mixture or in solution, to thereby unwind, align and extend molecules of the drag-reducing substance; b) passing the second fluid by a vortex chamber, to establish a vortex within the vortex chamber, thereby reducing the vorticity of the second fluid; c) ejecting the second fluid through a first ejector, having an aperture in a wall, into the first fluid as said first fluid flows past said wall, said aperture formed to include a first Coanda surface as a portion thereof.