Pin Fin Heat Shield for Gas Turbine Combustor
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Solution Overview
Problem
The existing heat shields in gas turbine engines face issues with coolant distribution and durability due to the introduction of circumferential rails, which cause extra contact points, hot spots, and stiffness discontinuity, affecting overall performance and durability.
Innovation Solution
A heat shield unit with pin fins arranged in arrays of different densities, where the density is lower in the upstream portion and higher in the downstream portion, allowing for optimized coolant distribution and flow, and connectors to secure the panel body to the combustor liner with fluid-coolant injection apertures aligned between these portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circumferential rails and deflectors are added among pin fin arrays to ensure optimal coolant distribution, then coolant distribution is improved, but durability deteriorates due to extra contact points, hot spots, and stiffness discontinuity
Solution Approach 1:
The patent removes the circumferential rails and deflectors from the heat shield structure, extracting the harmful elements that caused contact points and stiffness discontinuities. The coolant distribution function is achieved through alternative means (pin fin geometry and arrangement) that do not introduce the durability problems associated with rails.
Solution Approach 2:
The patent employs pin fins with varying local densities arranged in specific patterns to achieve optimal coolant distribution without requiring additional structural elements. The pin fin array is designed with different densities in different regions to guide coolant flow locally, eliminating the need for circumferential rails while maintaining durability.
2Temperature
If pin fins are added for internal cooling of heat shields, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
The pin fins serve multiple functions simultaneously: they provide internal cooling through the pin fin array, guide coolant flow for film cooling, and eliminate the need for separate circumferential rails and deflectors. This multi-functionality reduces overall structural complexity while maintaining cooling effectiveness.
Solution Approach 2:
The patent combines the cooling function and the flow guidance function into a single integrated pin fin structure, merging what would traditionally require separate components (cooling channels and flow deflectors) into one unified element, thereby reducing device complexity.
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 coolant distribution and flow, reducing flow restrictions and improving durability by minimizing extra contact points and hot spots, thereby optimizing heat shield performance and fuel efficiency.
Implementation Method 1
A coolant fluid circulates between the pin fins, thereby cooling the heat shields. Spent coolant fluid is then directed onto the exposed surface of the heat shields to perform film cooling.
Implementation Method 2
the pin fins being arranged in arrays of at least two different densities of volume of pin fins per unit volume... with a first density of the at least two different densities being lower than a second density of the at least two different densities
Implementation Method 3
connectors to connect the panel body to the combustor liner with a line between the upstream portion and the downstream portion of the panel body being aligned with fluid-coolant injection apertures in the combustor liner
Data Source
AI summary
A heat shield unit for a gas turbine engine combustor comprises a panel body secured to a combustor liner. A first surface of the body is oriented toward a combustion zone of a combustor. A second surface is oriented toward the liner. The body is separated into upstream and downstream portions. Pin fins project from the second surface of the body. The pin fins are arranged in arrays of at least two different densities of volume of pin fins per unit volume. One density, lower than the second density, is in the upstream portion and another in the downstream portion of the body. Connectors connect the body to the liner with a line between the upstream and downstream portions of the body aligned with fluid-coolant injection apertures in the liner. A gas turbine engine combustor and a method for cooling a heat shield unit in a combustor liner of a gas turbine engine are also provided.