Turbomachinery rotor blade

Abstract

A turbomachinery rotor blade is provided having an aerofoil body, and a hole penetrating the aerofoil body from a suction surface to a pressure surface thereof. The hole is suitable to receive a lacing wire. The blade further has a protrusion from the suction or pressure surface. The protrusion extends in a downstream direction from a downstream side of the hole and/or extends in an upstream direction from an upstream side of the hole, thereby disturbing the suction or pressure surface to locally thicken the aerofoil body adjacent the hole. The maximum radial extent of the protrusion in the radially outward direction of the blade is radially coterminous with the outboard side of the hole, and the maximum radial extent of the protrusion in the radially inward direction of the blade is radially coterminous with the inboard side of the hole.

The invention claimed is: 
     
       1. A turbomachinery rotor blade having an aerofoil body, and a hole penetrating the aerofoil body from a suction surface to a pressure surface thereof, the hole being suitable to receive a lacing wire;
 wherein a protrusion from the suction or pressure surface extends in a downstream direction from a downstream side of the hole and/or extends in an upstream direction from an upstream side of the hole, the protrusion disturbing the suction or pressure surface to locally thicken the aerofoil body adjacent the hole, the maximum radial extent of the protrusion in the radially outward direction of the blade being radially coterminous with the outboard side of the hole, and the maximum radial extent of the protrusion in the radially inward direction of the blade being radially coterminous with the inboard side of the hole. 
 
     
     
       2. A blade according to  claim 1 , wherein the protrusion extends from the hole in the downstream direction, and the thickening produced by the protrusion reduces with increasing downstream distance from the hole. 
     
     
       3. A blade according to  claim 1 , wherein the protrusion extends from the hole in the upstream direction, and the thickening produced by the protrusion reduces with increasing upstream distance from the hole. 
     
     
       4. A blade according to  claim 1 , wherein the width of the protrusion in the radial direction of the blade reduces with increasing downstream distance from the hole. 
     
     
       5. A blade according to  claim 1 , wherein the protrusion extends in a downstream direction from the downstream side of the hole a distance which is less than four times the diameter of the hole as measured in the radial direction of the blade. 
     
     
       6. A blade according to  claim 1 , wherein the protrusion extends in an upstream direction from the upstream side of the hole a distance which is less than four times the diameter of the hole as measured in the radial direction of the blade. 
     
     
       7. A blade according to  claim 1 , wherein the maximum height of the protrusion above the adjacent undisturbed aerofoil surface is less than half the diameter of the hole as measured in the radial direction of the blade. 
     
     
       8. A blade according to  claim 1 , wherein the blade has a protrusion from the suction surface and a protrusion from the pressure surface. 
     
     
       9. A blade according to  claim 1 , wherein the blade is a turbine rotor blade or a compressor rotor blade. 
     
     
       10. A rotor having a row of blades according to  claim 1 , and further having a lacing wire received in the holes of the blades. 
     
     
       11. A turbocharger having the rotor of  claim 10 .