Shaped Rim Cavity Wing Airflow Control
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Solution Overview
Problem
Rim cavity regions in turbomachinery pose challenges as they lead to inefficiencies due to air leakage from the gas path into the cavity, affecting engine performance, particularly in turbine and compressor sections where purge air or high-pressure air escapes, reducing overall efficiency.
Innovation Solution
Shaped rim cavity wings with a geometrically designed lower surface and a point of maximum extent that controls airflow separation, creating a flow re-circulation path to minimize leakage by extending from rotating or stationary components, thereby reducing air flow from the rim cavity region into the gas path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wing seals extend from rotating or stationary components to prevent air leakage from the gas path into the rim cavity region, then sealing efficiency is improved, but device complexity increases
Solution Approach 1:
The wing seal is divided into multiple surfaces (lower surface, upper surface, leading surface, trailing surface) with distinct geometric functions. Each surface segment controls specific airflow patterns, allowing the seal to prevent leakage through distributed geometric features rather than a single complex structure.
Solution Approach 2:
The lower surface of the wing seal incorporates a curved geometry with a defined maximum extent that creates controlled flow separation and re-circulation zones. This curvature generates aerodynamic forces that enhance sealing effectiveness by manipulating airflow patterns around the seal interface.
2Temperature
If purge air is introduced into the rim cavity region to cool components in the turbine section, then temperature control is improved, but energy loss increases
Solution Approach 1:
The wing seal acts as an intermediary structure between the gas path and rim cavity region. It allows controlled interaction between the two regions, enabling cooling air to be introduced when needed while preventing uncontrolled leakage that would waste energy. The seal mediates the trade-off between cooling requirements and energy conservation.
Solution Approach 2:
The wing seal geometry is designed to change airflow parameters (pressure, velocity, direction) as air moves from the gas path into the rim cavity region. By controlling these parameter changes, the system can introduce cooling air efficiently while minimizing energy loss through optimized flow management.
3Reliability
If high pressure air is used to pressurize the rim cavity region in the compressor section, then prevention of air escape is improved, but energy consumption increases
Solution Approach 1:
The wing seal uses the existing pressure differential between the gas path and rim cavity region to generate its own sealing force through aerodynamic pressure on its surfaces. Rather than requiring external energy input to maintain pressurization, the seal structure itself harnesses the flow field to create the necessary pressure distribution for effective sealing.
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
The shaped rim cavity wings effectively decrease the leakage gap, enhancing sealing efficiency and reducing purge flow requirements, thereby improving the overall performance and efficiency of turbomachinery by preventing air from escaping into the gas path.
Implementation Method 1
The lower surface has a geometric shape to control the separation of airflow as it passes around the lower surface to the upper surface
Data Source
AI summary
A shaped rim cavity wing includes an upper surface and a lower surface. The lower surface has a geometric shape to control the separation of airflow as it passes around the lower surface to the top surface. A point of maximum extent defines the boundary between the upper surface and the lower surface, wherein the point of maximum extent defines a corner that that separates airflow from the shaped rim cavity rim and creates a flow re-circulation adjacent to the top surface of the shaped rim cavity wing.