Gas Turbine Airfoil Bands With Hills and Valleys for Bow Wave Mitigation
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Solution Overview
Problem
Bow waves generated at the interface between components in gas turbine engines cause ingestion of hot combustion gases, leading to increased component temperatures and decreased durability and performance.
Innovation Solution
Implementing a contoured surface with a combination of hills and valleys upstream of airfoils to reduce the circumferential pressure gradient, thereby minimizing the ingestion of hot combustion gases into engine components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If combustion gases flow through the turbine engine, then power generation is achieved, but bow waves cause ingestion of hot gases into components increasing temperature and decreasing durability
Solution Approach 1:
The contoured surface with hills and valleys is positioned upstream of the airfoils to preemptively modify the flow field before bow waves reach the critical interfaces. This preliminary action reduces the circumferential pressure gradient and minimizes hot gas ingestion before it can cause damage to turbine components.
Solution Approach 2:
The contoured surface introduces localized geometric features (hills and valleys) at specific locations upstream of the airfoils. These localized modifications create targeted flow control zones that reduce pressure gradients at critical interfaces without affecting the overall engine power generation capability.
2Stress or pressure
If bow waves reflect combustion gases upstream, then pressure variations occur, but this causes ingestion of hot gases heating components and decreasing performance
Solution Approach 1:
By positioning the contoured surface upstream of the airfoils, the patent performs preliminary flow modification that prevents bow wave-induced pressure variations from propagating to critical interfaces. This preemptive action maintains more uniform pressure distribution and prevents hot gas ingestion that would otherwise reduce engine performance.
Solution Approach 2:
The contoured surface modifies flow parameters (pressure gradient, flow direction) in the upstream region. The hills and valleys create localized changes in static pressure and flow velocity that reduce the overall circumferential pressure gradient, thereby minimizing bow wave effects and maintaining engine performance.
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
Reduces the need for additional cooling and enhances the durability of turbine engine components by minimizing the ingestion of hot gases, thus improving engine performance.
Implementation Method 1
reduce the circumferential pressure gradient
Implementation Method 2
a pressure or bow wave may reflect a portion of the combustion gases upstream
Data Source
AI summary
A gas turbine engine includes a turbomachine having a compressor section, a combustion section, and a turbine section. The turbine section includes a band having an upstream end and a downstream end. The band extends between the upstream end and the downstream end, and the band at least partially defines the working gas flow path. A plurality of airfoils extend into the working gas flow path from the band. Each airfoil of the plurality of airfoils includes a leading edge, a trailing edge, a first side, and a second side opposite the first side. Each of the plurality of airfoils is substantially symmetric across an airfoil centerline extending through a center of each of the plurality of airfoils. The band defines a valley portion adjacent the leading edge of each of the plurality of airfoils and a pair of hill portions on opposing sides of the valley portion.