Gas Turbine Blade Root Raised Areas for Secondary Flow Control
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Solution Overview
Problem
Existing gas turbine blade designs fail to effectively reduce secondary flows, such as channel vortices, which lead to increased losses and suboptimal inflow conditions in the annular space duct.
Innovation Solution
The blade design features raised areas on both the pressure and suction sides, with the highest points of these areas positioned close to the airfoil edges, extending within the axial forward half, to influence the static pressure field and reduce secondary flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional annular space geometry is used, then the structure is simple, but secondary flows and channel vortices occur leading to increased losses
Solution Approach 1:
The patent applies local quality by creating raised areas at specific locations on the blade root - namely on the pressure side and suction side at particular radial positions. These localized modifications allow the structure to remain mostly simple while introducing flow-controlling features only where needed to reduce secondary flows and channel vortices, thereby reducing losses without substantially increasing overall structural complexity.
Solution Approach 2:
The patent introduces a radial dimension variation by raising areas from the blade root surface into the annular space channel. This third dimension (radial protrusion) allows the flow to be guided and controlled in a way that two-dimensional blade profiles cannot achieve alone, effectively reducing secondary flows while maintaining aerodynamic efficiency.
2Reliability
If raised areas are added to influence flow conditions, then secondary flows are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent modifies geometric parameters of the blade root by defining raised areas with specific radial heights, axial positions, and circumferential locations. These parameter changes are designed to optimize flow conditions and reduce secondary flows. The parameters are carefully selected to balance performance improvement with manufacturability, allowing the raised areas to be formed through conventional casting or machining processes without requiring complex assembly operations.
3Reliability
If the highest point of raised areas is positioned close to the airfoil edges, then flow control is optimized, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies that the highest points of the raised areas should be positioned close to, but not necessarily touching, the pressure side and suction side of the airfoil. This localized positioning requirement creates a clear manufacturing target that can be achieved with standard precision tolerances. The raised areas are designed to extend radially inward from the blade root, with their peak positions carefully controlled to optimize flow control while remaining within achievable manufacturing precision limits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances flow conditions by minimizing secondary flows, reducing losses, and improving the inflow onto downstream blade cascades.
Implementation Method 1
allows the static pressure field at the side walls and blade edges to be influenced in such a way as to reduce secondary flows
Implementation Method 2
enhances flow conditions by minimizing secondary flows, reducing losses, and improving the inflow onto downstream blade cascades
Data Source
Figure 1
AI summary
The invention relates to a blade (10), in particular of a turbine stage, of a gas turbine, in particular of an aircraft gas turbine, with a blade root and a blade (11) connected to the blade root, wherein the blade (11) has a pressure side (14) and a suction side (12), and wherein the blade root has at least one raised area (20, 24) on its radial outer surface facing the blade. According to the invention, it is proposed that the blade (10) has a first raised area (20) on the pressure side (14) and a second raised area (24) on the suction side (12), wherein a highest point (22) of the first raised area (20) is arranged substantially directly adjacent to the pressure side (14), and a highest point (26) of the second raised area (24) is arranged substantially directly adjacent to the suction side (12).