Compressor Shroud Apertures Mitigating Flow Separation
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Solution Overview
Problem
Compressor shroud bleed systems in gas turbine engines experience performance losses due to momentum exchange between the bleed cavity flow and the main gas path flow, leading to flow separation and reduced pressure recovery.
Innovation Solution
An annular compressor shroud design with inner and outer radial panels, forward and aft panels, and a unique offtake passage defined by apertures in the inner radial panel segment, which facilitate airflow between the interior region and the offtake passage, thereby mitigating flow blockage and improving pressure recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the bleed system is controlled to bleed air (offtake), then the bleed air can be used for cooling and pressurization purposes, but local flow separation increases the pressure difference between bleed cavity flow and main gas path flow, resulting in main flow performance loss and reduced pressure recovery inside the bleed cavity
Solution Approach 1:
The inner radial panel is segmented into a fixed portion and a movable portion that can independently deflect. This segmentation allows the movable portion to adjust its position to control flow separation at the offtake passage entrance, reducing turbulence and improving pressure recovery while maintaining the cooling capability provided by the bleed air system
Solution Approach 2:
The inner radial panel portion is made movable rather than fixed, allowing it to dynamically adjust its deflection angle in response to operating conditions. This dynamic adjustment optimizes the flow pattern at the offtake passage entrance, minimizing flow separation and pressure loss while maintaining effective bleed air extraction for cooling purposes
2Ease of operation
If the inner radial panel segment extends into the interior region to define the offtake passage, then the offtake can be controlled, but flow blockage and velocity increase within the offtake passage, leading to performance losses
Solution Approach 1:
The inner radial panel portion is made movable to dynamically control the offtake passage geometry. By adjusting the deflection angle of this movable portion, the system optimizes flow velocity and pressure distribution within the offtake passage, reducing flow blockage effects and minimizing performance losses while maintaining precise control over bleed air extraction
Solution Approach 2:
The deflection angle of the inner radial panel portion is varied as a control parameter to optimize flow characteristics. By changing this geometric parameter, the system adjusts the flow velocity and pressure recovery within the offtake passage, reducing flow blockage and minimizing performance losses while maintaining effective offtake control
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 design reduces flow blockage and velocity within the offtake passage, minimizing performance losses and enhancing the efficiency of the compressor bleed system by improving airflow patterns and pressure recovery.
Implementation Method 1
local flow separation can increase the pressure difference between flow inside bleed cavity and main gas path flow
Data Source
AI summary
An annular compressor shroud for a turbine engine that extends along an engine axial centerline is provided. The compressor shroud includes inner and outer radial panels, forward and aft panels, an airflow exit opening, and an offtake. The panels collectively define an annular interior region. The airflow exit opening is disposed within the outer radial panel. The offtake is disposed in the inner radial panel and includes an offtake passage. The inner radial panel segment has an interior surface contiguous with the interior region and an exterior surface that is opposite the interior surface. The exterior surface is contiguous with the offtake passage. A plurality of apertures are disposed in the inner radial panel segment. Each aperture is configured to permit airflow between the interior region and the offtake passage.