Combustor Quench Aperture Cooling via Impingement
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Solution Overview
Problem
Turbine engine combustors face challenges with high thermal stresses in quench aperture grommets and heat shields due to high temperatures, which can lead to material degradation and reduced engine performance.
Innovation Solution
The design incorporates a combustor wall with a shell, heat shield, and an annular body that defines a quench aperture, featuring a funnel-shaped portion of the shell to direct cooling air into a cooling cavity between the shell and heat shield, reducing thermal stresses through impingement cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If quench aperture grommets and heat shields are exposed to high temperatures during engine operation, then the combustor can maintain combustion function, but thermal stresses increase causing material degradation and reduced reliability
Solution Approach 1:
The combustor wall is segmented into multiple functional layers: shell, cooling cavity, heat shield, and quench aperture grommets. This segmentation allows each component to perform its specific function - the shell provides structural support, the cooling cavity channels cooling air, the heat shield protects internal components, and the grommets seal the quench apertures. This modular structure enables targeted cooling and stress management for each component.
Solution Approach 2:
A cooling cavity is introduced as an intermediary between the hot combustion chamber and the combustor wall components. This cooling cavity channels cooling air that impinges on the outer surface of the heat shield and quench aperture grommets, creating a thermal barrier that reduces thermal stresses on these components while allowing the combustion chamber to maintain high temperatures for proper combustion function.
2Reliability
If cooling air is directed to impinge on the annular body and heat shield, then thermal stresses are reduced, but the device complexity increases due to additional cooling structures
Solution Approach 1:
The cooling functionality is merged into the existing combustor wall structure. The cooling cavity is formed as an integral part of the combustor wall assembly, with cooling air passages integrated into the shell and heat shield structure. The quench aperture grommets are positioned within the cooling cavity environment, combining sealing and thermal protection functions. This integration avoids adding separate external cooling systems.
Solution Approach 2:
The cooling system utilizes engine operating air as the cooling medium, which is already present in the combustor environment. The cooling cavity structure itself serves as the cooling channel, and the heat shield and grommets are positioned to automatically receive cooling air impingement during normal engine operation without requiring additional active cooling mechanisms.
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 effectively reduces thermal stresses and enhances the durability of quench aperture components by directing cooling air to impinge on the annular body and heat shield, improving the overall performance and longevity of the turbine engine.
Implementation Method 1
The shell defines a cooling aperture that is fluidly coupled with a cooling cavity between the shell and the heat shield. The funnel-shaped portion of the shell may be adapted to direct air through the cooling aperture and into the cooling cavity to impinge against the body.
Implementation Method 2
directing cooling air to impinge on the annular body and heat shield, reducing thermal stresses
Data Source
AI summary
An assembly is provided for a turbine engine. This turbine engine assembly includes a combustor wall. The combustor wall includes a shell, a heat shield and an annular body. The annular body extends through the combustor wall and at least partially defines a quench aperture along a centerline through the combustor wall. The shell defines a first cooling aperture radially outwards of the annular body relative to the centerline and is configured to direct air to impinge against a portion of the annular body between the heat shield and the shell.