Patent ID: 8573941
Filing Date: 2013-11-05
Classification: F01D,F04D,F05D,Y02T

Abstract:
1. A tandem blade design of an axial turbomachine comprising a front blade and a rear blade offset from the front blade in the circumferential and axial directions, wherein the rear blade is profiled and positioned relative to the front blade so that in the predetermined operating range the rear blade interacts with the front blade and raises the air speed level at the trailing edge of the front blade wherein the front and rear blades partially overlap viewed both in a flow direction and in the circumferential direction; wherein the front blade has a convex curvature in its rear section such that in the predetermined operating range a flow detachment occurs at its suction face without interaction with the rear blade with a turbulent boundary layer; wherein the suction face of the rear blade is in facing relation with the pressure face of the front blade and detachment of the flow at the suction face of the front blade can be prevented by the increase of the speed level brought about by the rear blade; and wherein the rear blade has a small to negative curvature in its forward region, followed by a middle region with high curvature that together with the trailing edge of the front blade lies in a plane perpendicular to the flow wherein the front blade has a change of algebraic sign of the curvature on the pressure face upstream from the region of convex curvature.