Compressor Surge Protection via Membrane Leakage
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Solution Overview
Problem
Existing leakage devices for turbomachines, particularly axial compressors, are complex and costly due to the need for high-performance control systems, leading to inefficiencies and potential mechanical damage from surge phenomena like pumping, which require complex and expensive control mechanisms and result in non-optimal operation during transients.
Innovation Solution
A simple and economical leakage device featuring a hollow insert with a membrane having notches that deforms under pressure differences, allowing calibrated and intermittent leaks only when necessary, utilizing materials like shape memory alloys or polymers for minimal deformation and easy production and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex controlled leakage devices with movable plugs and membranes are used to protect against pumping, then the compressor is protected from surge phenomena, but the device complexity and cost increase significantly
Solution Approach 1:
The leakage device operates autonomously without external control systems. The membrane deforms automatically in response to pressure differences between the compressor discharge and suction, opening or closing the leakage orifices based on real-time surge conditions. This self-regulating mechanism eliminates the need for complex control devices, sensors, and actuators while maintaining reliable protection against pumping.
Solution Approach 2:
The invention replaces complex mechanical control systems (movable plugs, controlled valves, electronic sensors) with a simple elastic membrane mechanism. The membrane's elastic deformation directly controls the leakage orifices through pure mechanical response to pressure differential, substituting sophisticated control architecture with an elegant passive mechanical system.
2Reliability
If active controlled leakage devices are used to manage surge, then protection is achieved, but the cost and maintenance requirements increase
Solution Approach 1:
The leakage device uses simple, inexpensive components that can be easily replaced if needed. The membrane is a basic elastic element rather than a complex actuator or sensor, and the housing contains simple leakage orifices. This architecture allows for low-cost maintenance and replacement, making the device economically viable for long-term operation.
3Productivity
If predefined FADEC control settings are used for leakage, then operation follows a programmed schedule, but performance is non-optimal during transients
Solution Approach 1:
The membrane-based leakage device provides continuous real-time feedback response to surge conditions. The membrane deforms immediately in response to pressure differential changes, automatically adjusting the leakage rate to match actual surge intensity. This closed-loop feedback mechanism eliminates the lag and non-optimality inherent in predefined FADEC schedules, delivering optimal performance during transient operations.
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 solution effectively limits and stops surge phenomena by creating controlled leaks at specific points, reducing mechanical stress and maintaining compressor performance with reduced complexity and cost, while allowing for optimized flow balance through programmed recirculation of air.
Implementation Method 1
the membrane comprising at least one notch; the membrane being of a material and of a geometry such that it is capable of deforming near the notch in the presence of a pressure difference between its outer and inner surfaces
Implementation Method 2
the membrane being of a material and of a geometry such that it is capable of deforming near the notch
Implementation Method 3
utilizing materials like shape memory alloys or polymers for minimal deformation
Data Source
Figure 1~4
Figure 5
AI summary
The invention relates to a passive leakage device for an axial turbomachine, more specifically for a low-pressure compressor of an axial turbomachine. The device is intended to reduce and/or eliminate pumping phenomena within the machine. It comprises an insert (2), generally cylindrical in shape, with a flange (8) at one end and a bottom or diaphragm (6) at the other. The diaphragm has two cross-shaped notches, these notches being designed to allow deformation of the diaphragm under a pressure exceeding a predetermined threshold, thus permitting leakage through the diaphragm. Several inserts (2) are arranged through the casing wall (12) of a compressor, distributed over one or more circumferences of the casing, opposite one or more rows of rotor blades.In the case of a dual-flow turbomachine such as a turbojet, the primary and secondary flow separation nozzle is used to form a communication chamber between the inserts and to compensate with the pressure prevailing in the secondary flow.