Nested Bleed Plenums for Multi-Stage Compressor Pressure Management
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Solution Overview
Problem
Conventional multi-stage compressor configurations face challenges in providing multiple bleed flows at different pressures from a single compressor, as large delivery requirements for bleeds like cabin air leave limited space for additional bleeds, making it difficult to accommodate multiple bleeds with conventional plenum and bleed system configurations.
Innovation Solution
The configuration includes a first and second outer casing with overlapping bleed plenums, where the second bleed plenum fluidly communicates with its port via a duct that passes through the first bleed plenum, allowing for relative movement and accommodating multiple bleeds at different pressures by using ducts with features like bellows and inner sleeves to reduce turbulence and accommodate space constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large port is formed in the outer casing to accommodate cabin air bleed flow, then the delivery requirement for cabin air is met, but there is little or no space left for providing additional bleeds of different pressures from the same compressor
Solution Approach 1:
The patent implements nested bleed plenums where a first bleed plenum and one or more second bleed plenums are located concentrically between the first and second outer casings. The second bleed plenum is radially inward of the first outer casing while the first bleed plenum is radially outward of the second bleed plenum, creating a nested configuration that maximizes space utilization and enables multiple bleed flows at different pressures from the same compressor.
Solution Approach 2:
The patent utilizes the radial dimension by positioning bleed plenums at different radial locations between the first and second outer casings. The first bleed plenum is located radially outward of the second bleed plenum, allowing multiple bleed flows to be accommodated in the radial direction rather than competing for the same axial or circumferential space.
2Adaptability or versatility
If multiple bleed plenums are positioned at different radial locations, then multiple bleeds at different pressures can be accommodated, but the ducts must accommodate relative movement between the first and second outer casings
Solution Approach 1:
The patent employs flexible bellows in the ducts that connect the bleed plenums to the ports in the outer casing. The bellows are configured to accommodate relative movement between the first and second outer casings, providing flexibility and movement accommodation while maintaining the integrity of the bleed air passages.
Solution Approach 2:
The duct system incorporates movable elements including bellows and telescopic sections that allow the ducts to dynamically adjust to relative movement between the first and second outer casings. This dynamic configuration enables the system to accommodate thermal expansion, vibration, and assembly tolerances while maintaining sealed connections.
Data Source
AI summary
The present invention provides a multi-stage compressor for a gas turbine engine. The compressor has: a first outer casing, a second outer casing radially outward of the first outer casing, and a first bleed plenum one or more second bleed plenums located between the first and second outer casings and arranged to receive, in use, bleed flows of compressed air from respective stages of the compressor and to send the bleed flows to respective ports in the second outer casing. The first bleed plenum overlaps the, or each, second bleed plenum such that the, or each, second bleed plenum fluidly communicates with its port via a respective duct which, on extending between an off-take from the second bleed plenum to the port, passes through the first bleed plenum. The, or each, duct is configured to accommodate relative movement between the first and second outer casings.