摘要:
Selon l'invention, le procédé pour réaliser un élément de liaison (12), disposé entre deux pièces (5, 11) d'une structure (1), notamment de turboréacteur, qui est soumis à des efforts de compression et/ou de traction et qui est formé d'un fût (14) creux plongé, au moins partielle¬ ment, dans un flux d'air (Ff) s'écoulant entre les deux pièces (5, 11), est caractérisé par le fait qu'il comprend les étapes suivantes : on dimensionne la largeur du maître couple associé au fût (14) de l'élément de liaison (12), dans une direction orthogonale à l'axe longitudinal du fût en fonction de la résistance mécanique et de la masse souhaitées et des caractéristiques du flux d'air (Ff); et on travaille la surface externe du fût (14) de l'élément de liaison (12), sur au moins une partie, pour lui appliquer un état de surface dont la rugosité moyenne arithmétique est au moins égale à 20 micromètres, de manière à réduire la traînée de l'élément de liaison ainsi dimensionné par rapport à un élément de liaison lisse de même diamètre.
摘要:
The invention relates to a turbine blade intended for use in the wet steam region in penultimate and final turbine stages. The blade is subjected to wear by erosion by impinging water droplets and is treated in the vicinity of the inlet edges and parts of the blade element (1) in such a way as to reduce that erosive wear. One particularly advantageous way of reducing the erosive wear of the water droplets lies in providing the blade element (1) in the vicinity of its inlet edge (2) and back, or at least in a partial region thereof, with a surface roughness (3) which is substantially reinforced compared to the surface roughness at the front of the blade element (1).
摘要:
A turbine fan blade (40) adapted to trip and control a boundary layer transition at a side surface of the blade (40) during operation as a component in a turbine fan assembly (35). The turbine fan blade (40) includes a leading edge (55), a trailing edge (58), and two side surfaces including a high-pressure side surface (49) and a low-pressure side surface (52). At least one of the two side surfaces has an essentially smooth surface portion (61) located between the leading and trailing edges, and the essentially smooth surface portion is interrupted by a surface deviation (64). The surface deviation is configured to trip a positionally stabilized boundary layer transition (24) at a location toward the trailing edge from the surface deviation during operation of the turbine fan blade in the turbine fan assembly. In this manner, fatigue inducing aerodynamic forces experienced upon the blade during operation are controlled.
摘要:
For the purpose of reducing the inevitable noise from the flow of air over a rotating wind turbine wing part of the wing surface is provided with means for changing its acoustic reflection. These means for changing the acoustic reflection may be formed in an indentation on the upper side provided with a sound absorbing material, or provided with a plate mounted on compliant parts. A possibility is also to provide the indentation with a resonance-absorbing element. A final possibility is to provide the upper side, the lower side, or the trailing edge of the wing with openings leading to one or several cavities inside the wing. By the invention the means for changing the acoustic reflection are integrated into the wing, so that the flow around the wing is unaffected and the noise from the different noise sources are reduced in an effective way.
摘要:
A flow directing element (such as a rotor blade (34) or a stator vane (44)) for the turbine section (16) of a rotary machine is disclosed. Various construction details are developed which increase the aerodynamic efficiency of the flow directing element. In one embodiment, the flow directing element is a rotor blade (34) having a roughened surface which approximates the critical roughness characteristic of the airfoil. In one particular embodiment, the roughness average of the surface lies between 120 to 200 AA microinches.
摘要:
Disclosed herein is a centrifugal fan. The centrifugal fan having a plurality of blades includes a noise reduction portion formed on a pressure surface of each blade so as to be capable of effectively reducing noise of the centrifugal fan.
摘要:
A fan blade comprises a main body having an airfoil extending between a leading edge and a trailing edge. The fan blade has at least one of a channel closed by a cover, and an end cap covering at least one of the leading and trailing edges. At least one of a cover and an end cap has a pair of opposed ends. A step is defined extending from at least one of a suction wall and a pressure wall of the airfoil, to an outer surface of the one of a cover and an end cap at one of the opposed ends, and the step being less than or equal to about 0.010 inch (0.0254 centimeter) in dimension.
摘要:
The surface (12) of a body (10) immersed in a fluid flow has projections (14) on the base surface. In order to design a more flow-favourable surface (12) of a body (10) immersed in a fluid flow and having projections (14) on the base surface, the projections (14) are surrounded by two demarcation lines (18, 20), as seen from above the surface (12). The first demarcation line (18) is longer and more curved than the other demarcation line (20), so that the projections (14) have the cross-sectional area of an airfoil.
摘要:
Die Erfindung betrifft ein Laufrad (IMP) einer Radialturbofluidenergiemaschine (RTF) umfassend - eine Radscheibe (SW), - eine Deckscheibe (CW), - Schaufeln (BL), - eine Nabe (HB), wobei die Nabe (HB) derart ausgebildet ist, auf einer sich entlang einer Achse (X) erstreckenden Welle (SH) montiert zu werden, wobei die Radscheibe (SW) sich von der Nabe (HB) ausgehend im Wesentlichen radial erstreckt, wobei die Deckscheibe (CW) mittels der Schaufeln (BL) mit der Radscheibe (SW) verbunden ist, derart, dass zwischen der Radscheibe (SW) und der Deckscheibe (CW) durch die Schaufeln (BL) in Umfangsrichtung in mindestens einem Radialbereich des Laufrads (IMP) in Umfangsrichtung voneinander getrennte Strömungskanäle (FC) definiert sind, wobei das Laufrad (IMP) einen ersten Strömungspfaddurchtritt (O1) in im Wesentlichen axialer Richtung in radialer Nähe zu der Nabe (HB) aufweist, wobei das Laufrad (IMP) einen zweiten Strömungspfaddurchtritt (O2) in im Wesentlichen radialer Richtung radial weiter entfernt von der Nabe (HB) aufweist als der erste Strömungspfaddurchtritt (O1). Zur Reduktion von Verlusten der Strömung bei gleichzeitig optimiertem Fertigungsaufwand wird vorgeschlagen, dass die der Radscheibe (SW) zugewendete Oberfläche der Deckscheibe (CW) zumindest bereichsweise eine geringere Rauheit aufweist als die der Deckscheibe (CW) zugewendete Oberfläche der Radscheibe (SW). Daneben schlägt die Erfindung eine entsprechende Stufe, ein Verfahren zur Erzeugung eines umströmten Bauteils und ein entsprechend hergestelltes Bauteil vor.