Tip Leakage Control Channel for Turbine Blade Aerodynamic Loss Reduction
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Solution Overview
Problem
Turbine engines face inefficiencies due to tip leakage of compressed gases between rotor blades and stator vanes, which leads to aerodynamic losses and reduced efficiency, as existing solutions cannot completely eliminate these leaks due to clearance requirements for thermal and centrifugal growth.
Innovation Solution
The design incorporates a tip leakage control channel with a control channel floor and vanes, along with an internal cooling cavity and channel cooling aperture, to redirect and manage leakage airflow, reducing its momentum conflict and integrating it more efficiently into the main flow, thereby minimizing tip leakage losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If tip clearance is reduced to minimize leakage flow, then tip leakage losses are reduced, but thermal and centrifugal growth variations cause clearance instability and potential contact
Solution Approach 1:
A tip leakage control channel is introduced as an intermediary structure between the rotor blade tip and stator vane. This channel captures the leakage flow at its origin and redirects it through a controlled path, mediating between the conflicting requirements of minimizing leakage and maintaining stable clearance. The control channel acts as a buffer that manages the leakage flow without requiring tighter mechanical clearances.
Solution Approach 2:
The invention converts the harmful leakage flow into a beneficial controlled stream. By capturing the leakage flow in the tip leakage control channel and redirecting it through the control channel floor and aperture, the previously wasted flow is now directed to impinge on the stator vane leading edge, creating a protective cooling effect and reducing the harmful vortex formation that causes energy losses.
2Loss of energy
If existing tip leakage control methods are used, then some leakage reduction is achieved, but complete elimination is impossible due to clearance requirements
Solution Approach 1:
The tip leakage control channel is positioned to capture leakage flow at its origin, before the flow can develop into large loss-inducing vortices. By intercepting and redirecting the leakage flow preemptively, the system prevents the formation of harmful flow patterns rather than attempting to address them after they develop.
Solution Approach 2:
The invention addresses the tip leakage problem by introducing a new dimensional approach - using a three-dimensional control channel structure with depth, width, and angled surfaces to manipulate the flow. The control channel floor and aperture create a multi-dimensional flow path that redirects leakage in a controlled manner, adding spatial complexity to solve the two-dimensional leakage problem.
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 design effectively reduces tip leakage vortices, enhances airflow integration, and increases efficiency by imparting chordwise momentum to the leakage flow, leading to improved performance and reduced aerodynamic losses.
Implementation Method 1
the at least one curved portion communicates the airflow parallel to a control channel floor of the tip leakage control channel
Implementation Method 2
imparting chordwise momentum to the leakage flow, leading to improved performance and reduced aerodynamic losses
Data Source
AI summary
An airfoil according to an example includes, among other things, a suction sidewall and a pressure sidewall. A tip wall extends from a leading edge to a trailing edge and joins respective outer ends of the suction and pressure sidewalls. A tip rib extends along a pressure side of the tip wall. A tip leakage control channel is provided at the tip wall and has a floor that extends between a first control channel vane sidewall and a second control channel vane sidewall established by a corresponding tip leakage control vane. Each of the tip leakage control vanes is contiguous with and extending from a suction side surface of the tip rib. The tip leakage channel extends toward the trailing edge while extending toward the suction sidewall. One or more of an internal cavity, a channel cooling aperture, and a sidewall microcircuit may be provided.