Patent Publication Number: US-2021164488-A1

Title: Radial Compressor Impeller

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The invention relates to a radial compressor impeller. 
     2. Description of Related Art 
     DE 10 2012 207 727 B4 discloses a radial compressor impeller having a hub-like main body and moving blades arranged on the hub-like main body. The hub-like main body provides a flow-guiding surface of the compressor impeller that increases in size from a flow inlet end of the radial compressor impeller in the direction of a flow outlet end of the radial compressor impeller in the radial direction. On the hub-like main body, first moving blades and second moving blades are arranged, wherein the first moving blades, seen in the axial direction and in the radial direction, are formed longer than the second moving blades, and wherein between each two adjacent first moving blades a second moving blade each is arranged. The first moving blades are also referred to as so-called main blades and the second moving blades also as so-called splitter blades. 
     SUMMARY OF THE INVENTION 
     During operation, the radial compressor impeller may heat up. There is a need for restricting the heating-up of the radial compressor impeller. There is also a need for improving aerodynamic characteristics of the radial compressor impeller, i.e. the flow guiding characteristics of the same. 
     Starting out from this, one aspect of the invention is based on creating a new type of radial compressor impeller. 
     The radial compressor impeller according to one aspect of the invention comprises third moving blades that are designed shorter than the second moving blades, wherein between each adjacent first and second moving blades a third moving blade each is arranged. 
     With the third moving blades, which in the axial direction and in the radial direction are formed shorter than the second moving blades, heat can be passed on to the flow to be guided by the radial compressor impeller in the region of the flow outlet end of the radial compressor impeller. By way of this, a heating-up of the radial compressor impeller during the operation can be limited. 
     Furthermore, aerodynamic characteristic of the radial compressor impeller in particular in a part load operation can be improved via the third moving blades with a view to an improved flow guidance in a region of the flow outlet end. 
     According to an advantageous further development, flow leading edges of the second moving blades, seen in the flow direction, are arranged downstream of flow leading edges of the first moving blades, wherein flow leading edges of the third moving blades, seen in the flow direction, are arranged downstream of the flow leading edges of the second moving blades. 
     According to an advantageous further development, the flow outlet end of the hub-like main body has an outlet radius, wherein the flow leading edges of the third moving blade are arranged in a range between 60% and 85% of the outlet radius. Flow trailing edges of the third moving blade are preferentially arranged in a range between 90% and 100% of the outlet radius. 
     In particular when the third moving blades, based on the outlet radius of the radial compressor impeller, are positioned in the range defined above, heat from the radial compressor impeller can be particularly advantageously passed on to the flow to be guided in the region of the flow outlet end of the radial compressor impeller. In the part load range of the radial compressor impeller, a particularly advantageous flow guidance is then possible. 
     According to an advantageous further development, the radial compressor impeller consists of an aluminium alloy or a magnesium alloy. One aspect of the invention is particularly advantageously employed with radial compressor impellers that are formed of an aluminium alloy or a magnesium alloy. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred further developments of the invention are obtained from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail by way of the drawing without being restricted to this. There it shows: 
         FIG. 1  is a perspective front view of a radial compressor impeller; 
         FIG. 2  is a perspective back view of the radial compressor; 
         FIG. 3  is a front view of the radial compressor impeller; and 
         FIG. 4  is a lateral view of the radial compressor impeller. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
       FIGS. 1 to 4  show different views of a radial compressor impeller  10 , wherein the radial compressor impeller  10  has a hub-like main body  11  and multiple moving blades  12  arranged on the hub-like main body  11 . 
     The hub-like main body  12  provides a flow-guiding surface  13  for the radial compressor impeller  10 , which increases in size from a flow inlet end  14  in the direction of a flow outlet end  15  of the radial compressor impeller  10  in the radial direction R. On this flow-guiding surface  13 , the moving blades  12  are formed, which originating from this flow-guiding surface  13  extend away in the radial direction R and in the axial direction A. These moving blades  12  are curved in the circumferential direction and provide further flow-guiding surfaces of the radial compressor impeller  10 . 
     On the hub-like main body  11 , different moving blades  12  are formed, namely first moving blades  12   a , second moving blades  12   b  and third moving blades  12   c.    
     The first moving blades  12   a  are formed longer, seen in the axial direction A and/or in the radial direction R, than the second moving blades  12   b . Between each two adjacent first moving blades  12   a , a second moving blade  12   b  each is arranged. 
     Seen it the axial direction A and/or in the radial direction R, the third moving blades  12   c  are formed shorter than the second moving blades  12   b . Between each adjacent first and second moving blades  12   a ,  12   b , a third moving blade  12   c  is arranged. 
     According to one aspect of the invention, the radial compressor impeller  10  accordingly comprises three different types of moving blades  12   a ,  12   b , and  12   c . Basically, the first moving blades  12   a  and the second moving blades  12   b  are known from the prior art. The third moving blades  12   c  are additionally employed which, seen in the radial direction and in the axial direction, each have the shortest extension of the three different moving blade types  12   a ,  12   b , and  12   c.    
     The third moving blades  12   c  are arranged adjacent to the flow outlet end  15  of the radial compressor impeller  10 . 
     The third moving blades  12   c  on the one hand assume a cooling function to pass heat from the radial compressor impeller  10  to the flow to be guided and compressed by the same, in the region of the flow outlet end  15 . On the other hand, the third moving blades  12   c  assume a flow guiding function which, in particular in the part load operation, is advantageous in order to provide in the part load operation an improved flow guidance and accordingly improved aerodynamic characteristics of the radial compressor impeller  10 . 
     Each of the moving blades  12   a ,  12   b , and  12   c  comprises a flow leading edge  16   a ,  16   b ,  16   c  and a flow trailing edge  17   a ,  17   b ,  17   c.    
     The flow leading edges  16   b  of the second moving blades  12   b  are arranged, seen in the axial direction and in the flow direction, downstream of the flow leading edges  16   a  of the first moving blades  12   a . The flow leading edges  16   c  of the third moving blades  12   c  are arranged, seen in the axial direction and in the flow direction, downstream of the flow leading edges  16   b  of the second moving blades  12   b.    
     In the shown exemplary embodiment, all flow trailing edges  17   a ,  17   b , and  17   c  of all moving blades  12   a ,  12   b , and  12   c  are arranged, seen in the radial direction and in the flow direction, in the same position. It is also possible that the flow trailing edges  17   c  of the third moving blades  12   c  are arranged, seen in the radial direction and in the flow direction, upstream of the flow trailing edges  17   a ,  17   b  of the first and second moving blades  12   a ,  12   c.    
     The flow trailing end  15  of the hub-like main body  11  and thus of the radial compressor impeller  10  is characterized by an outlet radius. The flow leading edges  16   c  of the third moving blades  12   c  are arranged in a range between 60% and 85% of this outlet radius. The flow trailing edges  17   c  of the third moving blades  12   c  are arranged in a range between 90% and 100% of this outlet radius. 
     Accordingly, the third moving blades  12   c  extend in a range between 60% and 100%, in particular in a range between 85% and 100% or in a range between 60% and 90% or also in a range between 85% and 90% of this outlet radius. 
     As already explained, heat can be optimally passed on with the third moving blades  12   c  from the radial compressor impeller  10  to the flow to be compressed. 
     In particular, the radial compressor impeller  10  including the moving blades  12   a ,  12   b ,  12   c  is manufactured from an aluminium alloy or from a magnesium alloy. 
     Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.