Axial Compressor Flow Recirculation for Stall Margin
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Solution Overview
Problem
The performance and stability of axial compressors are limited by the lower pressure ratio in rear stages, which restricts the overall pressure ratio and efficiency of the compressor.
Innovation Solution
A secondary fluid flow system is introduced, directing higher static pressure air from downstream stages into upstream stators to disrupt the main fluid flow, thereby improving the pressure ratio and stability by reducing the pressure gradient and increasing the margin to stall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional axial compressor design with progressive reduction in stage pressure ratio is used, then the compressor can be manufactured with standard multi-stage configuration, but the overall pressure ratio and stability are limited by the lower pressure ratio in rear stages
Solution Approach 1:
A secondary fluid flow system is introduced as an intermediary mechanism between downstream and upstream stages. This system directs fluid from downstream stages into upstream stators, acting as a mediator to disrupt adverse pressure gradients and improve overall compressor stability without requiring fundamental changes to the multi-stage configuration
Solution Approach 2:
The invention adds a secondary fluid flow dimension to the conventional single-direction axial flow path. By introducing fluid circulation between stages through secondary paths, the system creates additional flow control capabilities that enhance stability without altering the primary axial compression sequence
2Stress or pressure
If the pressure ratio in rear stages is increased to improve overall performance, then the overall pressure ratio improves, but the risk of stall increases due to higher pressure gradients
Solution Approach 1:
The secondary fluid flow system applies preliminary anti-action by introducing counter-flow from downstream to upstream stages before adverse pressure gradients can cause stall. This preemptive fluid injection disrupts developing instability and prevents stall conditions from occurring
Solution Approach 2:
The system dynamically alters flow parameters by varying the secondary fluid flow rate and direction. By changing these parameters, the system can optimize the pressure gradient distribution across stages to simultaneously achieve higher pressure ratios and maintain adequate stall margins
3Productivity
If a secondary fluid flow system is introduced to improve pressure ratio and stability, then performance and stall margin improve, but the device complexity increases
Solution Approach 1:
The secondary fluid flow system is designed with multi-functionality, serving multiple purposes: improving pressure ratio, enhancing stability, controlling stall margins, and optimizing flow distribution. This universal approach consolidates multiple control functions into a single integrated system rather than requiring separate mechanisms for each function
Solution Approach 2:
The system utilizes the compressor's own downstream fluid to serve upstream stages, creating a self-contained flow circulation system. The secondary flow draws from the compressor's existing fluid supply, eliminating the need for external pumps or separate fluid sources, thereby reducing overall system complexity
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 secondary air flow system enhances the performance and stability of the axial compressor by increasing the pressure ratio and stall margin, allowing for better compression efficiency and reduced risk of stall.
Implementation Method 1
directing the secondary fluid into a first stator of the first stage to disrupt a main fluid flow through the first stator, the main fluid flow through the first stator having a second static pressure that is different than the first static pressure
Data Source
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AI summary
Methods and apparatuses are provided for a compressor. The compressor includes a first stage having a first rotor and a first stator, and a second stage downstream from the first stage in a direction of a fluid flow. The compressor also includes a secondary flow system that directs fluid from the second stage into the first stator to improve at least one of a performance and a stability of the compressor.