Abstract:
A gas turbine vane, especially a vane pertaining to an aircraft engine, comprising a blade and a vane footing. The blade is defined by a flow inlet edge or a front edge, a flow outlet edge or a rear edge, and a blade surface extending between the front edge and the rear edge and forming a suction side and a pressure side. The suction side of the blade includes at least one microprofiled or microstructured region for optimizing the flow around the blade.

Description:
BACKGROUND 
     The present invention relates to a gas turbine vane, in particular a vane of an aircraft engine. 
     Gas turbines, such as aircraft engines for example, are made up of multiple subassemblies, namely a fan, preferably multiple compressors, a combustion chamber, and preferably multiple turbines. For improving the efficiency and the working range of such gas turbines it is necessary to optimize all subsystems or components of the gas turbine. The present invention relates to the improvement of the flow-around behavior of gas turbine vanes, in particular of rotary vanes of a compressor of the gas turbine. 
     As a rule, compressors of gas turbines are made up of multiple stages, which are situated axially consecutively in the flow, each stage being formed by a rotary vane ring formed by rotary vanes assigned to a rotor. The rotary vanes forming the rotary vane ring and assigned to the rotor rotate together with the rotor vis-à-vis the stationary guide vanes and a likewise stationary housing. For reducing manufacturing costs, an increasingly compact compressor design having the lowest possible number of stages is aimed for. Furthermore, the overall pressure conditions within the gas turbine and thus the pressure ratios between the individual stages increase due to the constant optimization of the efficiency and the working range of such compressors. 
     Increasingly larger stage pressure ratios and an increasingly smaller number of stages inevitably result in higher circumferential velocities of the rotating components of the compressor. The rotational speeds, which increase with the reduction of the number of stages, result in increasing mechanical stresses in particular on the rotary vanes rotating together with the rotor and in supersonic flow conditions within the vane grid. Such flow conditions require an optimized, aerodynamic design of the gas turbine vanes. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to create a novel gas turbine vane. 
     According to the present invention, the suction side of the blade of the gas turbine vane has at least one micro-profiled or micro-structured area to optimize a flow around the suction side or the blade. 
     In terms of the present invention, a gas turbine vane is proposed which has a clearly improved flow behavior. According to the present invention, at least one micro-profiled or micro-structured area is provided on the suction sides of the blades of gas turbine vanes for optimizing the efficiency of a gas turbine. According to the present invention, a flow separation, which is to be prevented, takes place on a gas turbine vane primarily on the suction side of the blade or the gas turbine vane, the suction side of a gas turbine vane being less heavily exposed to wear, e.g., erosion, or to contamination and therefore the suction side may be provided with effective micro-profiles or micro-structures. Using such micro-structures or micro-profiles of the gas turbine vane on its suction side, it is possible to stabilize the flow around the gas turbine vane and thus to optimize the operating range and ultimately the working range of the gas turbine. 
     According to an advantageous refinement of the present invention, the or each micro-profiled or micro-structured area is assigned to a section of the suction side of the blade at which flow deceleration takes place. This section extends in particular over between 30% and 70% of the profile depth of the blade. 
     The or each micro-profiled or micro-structured area has preferably a shark skin-like profile or structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred refinements of the present invention arise from the following description. An exemplary embodiment of the present invention is, without being limited thereto, explained in greater detail based on the drawings. 
         FIG. 1  shows a gas turbine vane according to the present invention in a first exemplary embodiment of the invention in a highly schematized, perspective side view, and 
         FIG. 2  shows a gas turbine vane according to the present invention in a second exemplary embodiment of the invention in a highly schematized, perspective side view. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention is described in greater detail in the following with reference to  FIGS. 1 and 2 . 
       FIG. 1  shows a gas turbine vane  10  according to the present invention in a perspective side view. Gas turbine vane  10  in  FIG. 1  includes a blade  11  as well as a vane foot  12  attached to it. Blade  11  is delimited by a flow inlet edge or front edge  13 , a flow outlet edge or rear edge  14  and a blade surface  15  extending between front edge  13  and rear edge  14 . Blade surface  15  forms a suction side  16  and a pressure side  17  of blade  11  of gas turbine vane  10 . 
     In terms of the present invention, at least one micro-structured or micro-profiled area is assigned to suction side  16  of blade  11 . 
     Only one single such micro-profiled or micro-structured area  18  is present in the exemplary embodiment of  FIG. 1 . According to  FIG. 1 , this area extends over the entire radial height of blade  11 . 
     Micro-profiled area  18  is assigned to a section of suction side  16  in which flow deceleration takes place. Starting at front edge  13  of blade  11  of gas turbine vane  10 , first a flow acceleration and subsequently a flow deceleration take place on suction side  16 . The danger of flow separation exists in particular in the areas of suction side  16  of blade  11  in which the flow deceleration takes place. In terms of the present invention, micro-profiled or micro-structured area  18  is precisely situated in this section of suction side  16  in which a flow deceleration takes place. This area extends preferably over between 30% and 70%, in particular between 30% and 50%, of the profile depth of blade  11 . It is thus assigned to a central area of suction side  16  of blade  11 . 
     Particularly preferred is an embodiment of the present invention in which micro-profiled or micro-structured area  18  has a shark skin-like profile or structure. Such a structured area  18  of suction side  16  of blade  11  creates a particularly preferred flow around gas turbine vane  10 . 
       FIG. 2  shows another exemplary embodiment of a gas turbine vane  19  according to the present invention. Since gas turbine vane  19  in  FIG. 2  corresponds in essence to gas turbine vane  10  in  FIG. 1 , the same reference numerals are used for the same subassemblies for the sake of avoiding unnecessary repetitions. Merely the differences between the two exemplary embodiments in  FIGS. 1 and 2  will be addressed in the following. 
     The exemplary embodiment in  FIG. 2  differs from the exemplary embodiment in  FIG. 1  in that multiple different micro-profiled or micro-structured areas are assigned to suction side  16  of blade  11 , namely three different areas  20 ,  21 , and  22  in the exemplary embodiment in  FIG. 2 . 
     In the area of suction side  16  of blade  11 , gas turbine vane  10  of the exemplary embodiment shown in  FIG. 2  has a first area  20  on the side of the vane foot, which has a micro-profile or a micro-structure as set forth in the present invention. This first area  20  on the side of the vane footing is assigned to an area of blade  11  that is exposed to high vibration stresses. Area  20  is preferably micro-profiled or micro-structured in such a way that blade  11  is strengthened in this area  20  and/or that compressive stresses are induced. This makes it possible to optimize the strength characteristics of blade  11  in addition to a positive effect on the flow around it. 
     Area  21 , radially externally adjacent to area  20 , also has a preferably shark skin-like micro-profile or a micro-structure, as in the exemplary embodiment in  FIG. 1 . 
     A third, micro-profiled or micro-structured area  22  is assigned to the radially externally positioned blade tip of blade  11 . This makes it possible, for example, to optimize the flow in the gap area between gas turbine vane  19 , designed as a rotary vane, and a stationary housing. 
     As shown in  FIG. 2 , both micro-profiled or micro-structured areas  20  and  22  extend over a larger section of the profile depth than micro-profiled or micro-structured area  21 . 
     A gas turbine vane is thus proposed where at least one micro-profiled or micro-structured area is assigned to the suction side of the blade of the gas turbine vane. This micro-profiled or micro-structured area is assigned to that section of the suction side of the blade which is particularly at risk regarding a possible flow separation. The present invention is based on the recognition that precisely this section of the suction side is only slightly stressed with regard to erosion or contamination, so that the micro-structured or micro-profiled area of the suction side of the blade retains its effectiveness even during operation of the gas turbine. In addition to optimizing the flow around the blade, the strength of the gas turbine vane may be positively affected with the aid of the micro-profiled or micro-structured areas. The improved flow around the gas turbine vanes, designed according to the present invention, results in a greater compression limit and thus in improved efficiency of the gas turbine. 
     The gas turbine vanes designed according to the present invention are rotary vanes preferably of a compressor of the gas turbine. 
     Finally, it should be pointed out that the or each micro-profiled area on the suction side of the gas turbine vane may be machined into the suction side of the blade in a defined manner using laser, sputtering, or other removal methods. Cost-effective production is possible since the suction side is provided with the or each micro-profiled area only in a narrowly limited section.