The invention relates to a blade-like profiled device that has a gas or a fluid flowing around it and exhibits, to improve the efficiency, blades with a lamellar profile between which, to shift the flow separation zone, in each case, a slot is placed that extends to a maximum width to the edge of the lamellar blade.
Such a device is known from DE-PS 3,105,183 and corresponding U.S. Pat. No. 4,687,416. But this device has the drawback that at considerable total lengths of the lamellar blades, the blades can oscillate due to their elasticity, which can impair the flow of the fluid or gas. Thus, to avoid these drawbacks, extraordinarily high quality materials are necessary, due to which the production costs of this known device are greatly increased. Further, it has been shown that, with this known device, the flow losses are certainly decreased by reducing the influence of flow vortices, but the increase of the efficiency and thus of the energy utilization is still limited.
The object of the invention is to improve the device of the type mentioned above so that, with simplified production, the efficiency is optimized and a general purpose application in parts that have fluids or gases flowing around them is achieved.
According to the invention, the object is achieved in that the blade-like device has a blade structure having slots running radially outwardly from a location that is at a distance from the root of the blade structure so as to form a spreading blade, as a slotted blade formed of a group of profiled blade elements having a laminar profile, and the blade elements of the slotted blade are placed relative to each other so that the blade edges of the blade elements, that are consecutive in the initial flow direction are configured offset relative to each other each in the direction of the pressure zone of the slotted blade profile. According to the invention, this device can be applied universally to parts that have gaseous or liquid fluids fluids around them, and thus are particularly suitable to the formation of foils, propeller blades of screw propellers and helicopter rotors, blades of ship hulls and keels, etc.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.