Gas Turbine Blade Root Inlet Orifice Cooling
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Solution Overview
Problem
Current gas turbine engine blade cooling systems face challenges in effectively distributing cooling air to reduce stress and thermal loads, particularly in the root and platform areas, which can lead to inefficiencies and potential damage due to centrifugal forces and complex casting requirements.
Innovation Solution
The design incorporates an inlet orifice located at 50% span or greater on the root's forward axial face, with a cooling passage that extends to outlet orifices on the gaspath side, featuring a serpentine section that turns at least 180° within the platform, facilitating stress reduction and efficient cooling by allowing cooling air to exit aft of the trailing end of the airfoil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is introduced at the root of the blade, then cooling effectiveness in the root area is improved, but centrifugal forces cause poor distribution of cooling air to the platform and forward section
Solution Approach 1:
Instead of introducing cooling air at the root and relying on centrifugal force to distribute it outward, the invention reverses the approach by introducing cooling air at the forward face (platform area) where it is needed, allowing the cooling air to naturally follow the gas flow direction and reach the root area without being hindered by centrifugal forces.
Solution Approach 2:
The invention replaces the mechanical reliance on centrifugal force for cooling air distribution with a flow-aligned approach where cooling air is introduced in the direction of the main gas flow, allowing aerodynamic forces to naturally distribute the cooling air throughout the blade structure without being opposed to centrifugal effects.
2Temperature
If complex casting is used to accommodate cooling passages, then cooling coverage is improved, but manufacturing complexity and potential clogging increase
Solution Approach 1:
The invention concentrates the cooling function at the critical forward face and platform area where thermal loads are highest, rather than distributing complex cooling passages throughout the entire blade. The single inlet orifice and associated cooling passage provide targeted cooling where it is most needed, simplifying the overall casting design.
Solution Approach 2:
The invention extracts the cooling function from the complex internal passage system and implements it through a simple inlet orifice on the forward face, separating the cooling air introduction function from the blade's structural casting and reducing manufacturing complexity while maintaining effective cooling coverage.
3Temperature
If inlet orifice is positioned at the root, then cooling access is improved, but stress concentrations and thermal loads increase in critical areas
Solution Approach 1:
Instead of placing the inlet orifice at the root as conventionally done, the invention inverts the approach by positioning it at the forward face, allowing cooling air to be introduced at the location of highest thermal load while avoiding stress concentration issues at the root attachment area.
Solution Approach 2:
The invention places the inlet orifice specifically at the forward face where thermal loads are most severe, providing localized cooling access exactly where needed without introducing stress concentrations in the root area where structural integrity is critical.
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 cooling efficiency by reducing stress and thermal loads, minimizing the need for complex casting and preventing clogging, while ensuring effective heat transfer and film cooling across the blade's surface.
Implementation Method 1
a cooling passage (78) within the root (68), the cooling passage (78) having an inlet (76) at a forward axial face (70) of the root (68)
Implementation Method 2
enhances cooling efficiency by reducing stress and thermal loads
Implementation Method 3
the cooling passage includes a serpentine section within the platform... the serpentine section turns at least 180°
Implementation Method 4
the outlet orifices open on the gaspath side of the platform, aft of the trailing end of the airfoil... ensuring effective heat transfer and film cooling across the blade's surface
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A gas turbine engine article includes a blade that has a platform, and airfoil, and a root. The platform has a gaspath side and a non-gaspath side. The airfoil extends radially from the gaspath side of the platform and defines a leading end and a trailing end. The root is configured to secure the blade. The root extends radially from the non-gaspath side of the platform and defines forward and aft axial faces. There is an inlet orifice in the forward axial face. A cooling passage extends from the inlet orifice, through the root, and into the platform.