Turbomachine and turbomachine stage

Abstract

A turbomachine stage including guide vanes, radially inner and/or radially outer airfoil platforms, which together form a guide vane cascade, and further including rotor blades, radially inner and/or radially outer airfoil platforms, which together form a rotor blade cascade adjacent to the guide vane cascade. Radially outer airfoil platforms have cascade regions extending between circumferentially adjacent airfoils, and gap regions which radially and/or axially bound an axial gap extending axially between the guide vane cascade and the rotor blade cascade. A contour of at least one of these gap regions varies, in particular periodically, in the radial and/or axial direction around the circumference.

What is claimed is: 
     
         1 . A turbomachine stage comprising:
 guide vanes;   a radially outer guide vane airfoil platform defining with the guide vanes a guide vane cascade, the radially outer guide vane airfoil platform having a guide vane cascade region and a guide vane gap region extending axially beyond the guide vane cascade region;   rotor blades;   a radially outer rotor vane airfoil platform defining with the rotor blades a rotor blade cascade, the radially outer rotor vane airfoil platform having a rotor vane cascade region and a rotor vane gap region extending axially beyond the rotor vane cascade region;   the rotor blade cascade being adjacent to the guide vane cascade, the guide vane gap region and the rotor vane gap region at least one of radially and axially defining an axial gap extending axially between the guide vane cascade and the rotor blade cascade;   a contour of at least one of the guide vane gap region and the rotor vane gap region varying in at least one of the radial and the axial direction around a circumference, and an at least one of axially and radially opposite contour of the other of the guide vane gap region and the rotor vane gap region varying around the circumference.   
     
     
         2 . The turbomachine stage as recited in  claim 1  wherein the contour and the opposite contour are radially opposite. 
     
     
         3 . The turbomachine stage as recited in  claim 2  wherein the contour and the opposite contour vary identically. 
     
     
         4 . The turbomachine stage as recited in  claim 1  wherein the contour varies both radially and axially. 
     
     
         5 . The turbomachine as recited in  claim 1  wherein the contour varially radially but is constant in the axial direction. 
     
     
         6 . The turbomachine stage as recited in  claim 1  wherein at least one of the guide vane or rotor vane gap region merges smoothly into the respective guide vane or rotor vane cascade region. 
     
     
         7 . The turbomachine stage as recited in  claim 1  wherein the contour varies radially and an extreme extent of the radially varying contour is circumferentially located in a pressure-side half of a segment between two respective adjacent airfoil leading edges or in a suction-side half of a segment between two respective adjacent airfoil trailing edges. 
     
     
         8 . The turbomachine stage as recited in  claim 1  wherein the contour varies radially and a maximum variation in the radial direction of the respectve guide vane or rotor vane gap region is no more than 50% of the pitch of the respective guide vane or rotor vane cascade. 
     
     
         9 . The turbomachine as recited in  claim 8  wherein the maximum variation is no more than 40%. 
     
     
         10 . The turbomachine stage as recited in  claim 1  wherein the contour varies axially and wherein an extreme extent of the axially varying contour is circumferentially located in the region of a respective airfoil edge. 
     
     
         11 . The turbomachine as recited in  claim 10  wherein the extreme extent is circumferentially spaced from the respective airfoil edge by no more than 25% of the cascade pitch. 
     
     
         12 . The turbomachine stage as recited in  claim 1  wherein the contour varies axially and a maximum variation in the axial direction is no more than 50% the pitch of the respective guide vane or rotor vane cascade. 
     
     
         13 . The turbomachine stage as recited in  claim 1  wherein the contour varies periodically. 
     
     
         14 . The turbomachine stage as recited in  claim 13  wherein the opposite contour varies identically with the contour. 
     
     
         15 . The turbomachine stage as recited in  claim 13  wherein the opposite contour varies identically with the contour. 
     
     
         16 . A turbomachine comprising at least one turbomachine stage as recited in  claim 1 . 
     
     
         17 . A gas turbine comprising at least one turbomachine stage as recited in  claim 1 . 
     
     
         18 . An aircraft engine gas turbine comprising at least one turbomachine stage as recited in  claim 1 . 
     
     
         19 . A compressor stage comprising the turbomachine stage as recited in  claim 1 . 
     
     
         20 . A turbine stage comprising the turbomachine stage as recited in  claim 1 .