Compressor Bleed Air Channel Balancing for Distortion Control
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Solution Overview
Problem
Circumferentially unbalanced bleed air extraction from gas turbine engines leads to compressor operability issues due to airflow distortion, necessitating mechanical adjustments that can be cumbersome and inefficient.
Innovation Solution
Implementing passive and active flow control devices, such as baffles with varying aperture sizes and positions, to manage compressor distortion by circumferentially balancing bleed air extraction, allowing for asymmetric bleed port geometry and adjustable airflow management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bleed air is extracted from the compressor section, then high pressure air is available for cabin pressurization and cooling, but compressor operability deteriorates due to airflow distortion
Solution Approach 1:
The patent applies local quality by varying the aperture sizes of individual bleed ports circumferentially around the compressor. Each bleed port has a specifically designed aperture size to balance the total bleed air extraction circumferentially, ensuring uniform airflow distribution while maintaining compressor operability. This local variation in aperture quality compensates for the harmful effects of bleed air extraction.
Solution Approach 2:
The patent employs asymmetry by using non-uniform aperture sizes for bleed ports at different circumferential positions. Rather than identical symmetric openings, the bleed ports are designed with asymmetric aperture dimensions to achieve circumferential flow balance. This asymmetric configuration allows precise control over bleed air distribution to maintain compressor performance.
2Reliability
If mechanical adjustments are made to balance bleed air extraction, then compressor distortion is reduced, but device complexity and ease of operation worsen due to cumbersome adjustments
Solution Approach 1:
The patent implements self-service by designing bleed ports with fixed, pre-calculated aperture sizes that automatically provide circumferential flow balance during normal operation. The asymmetric aperture configuration is built into the structure, eliminating the need for external mechanical adjustment mechanisms. The system self-regulates bleed air distribution through its inherent geometric design.
Solution Approach 2:
The patent replaces mechanical adjustment systems with a fixed geometric solution. Instead of using movable components, actuators, or adjustable mechanisms to balance bleed air flow, the invention uses precisely engineered static aperture sizes. This substitution eliminates complex mechanical systems while achieving the same flow balance objective.
3Ease of manufacture
If symmetric bleed port geometry is used, then manufacturing is simplified, but airflow balance deteriorates causing compressor distortion
Solution Approach 1:
The patent applies local quality by designing each bleed port with a specific aperture size tailored to its circumferential position. Rather than using identical symmetric geometry throughout, each location receives a customized aperture dimension to achieve optimal local flow balance. This localized differentiation maintains manufacturing feasibility while correcting airflow distribution issues.
Solution Approach 2:
The patent changes the geometric parameters of the bleed ports, specifically the aperture size, to optimize airflow balance. By varying this critical dimension across different circumferential positions, the design achieves uniform bleed air extraction without requiring complex asymmetric shapes. This parameter variation approach maintains ease of manufacture while improving airflow characteristics.
Data Source
AI summary
An engine includes a compressor including an inner casing and an outer casing where the inner casing defines a primary flow path for a primary airflow through the compressor. The inner casing and the outer casing define a bleed air cavity therebetween. The inner casing at least partially defines a bleed air channel extending circumferentially about the inner casing to direct a bleed airflow from the primary airflow into the bleed air cavity. One or more flow control devices located circumferentially about the compressor to actively or passively circumferentially balance a flow of the bleed airflow into the bleed air cavity or within the bleed air cavity, wherein the one or more flow control devices are disposed at least partially within the bleed air channel, form at least part of the bleed air channel, or extend axially aft from the bleed air channel.