Centrifugal Compressor Parallel Flow Guide Vanes Surge Margin
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Solution Overview
Problem
Centrifugal compressors face limitations in surge margin and choke flow rate due to increased intake-air resistance and turbulence caused by existing nose cone and guide vane configurations, leading to decreased compression efficiency and operational range.
Innovation Solution
A centrifugal compressor design featuring a parallel flow generating unit with guide vanes and a recirculation channel that rectifies intake air to flow parallel to the rotation shaft, reducing resistance and turbulence by optimizing the recirculation port and guide vane configuration, including a central intake-air flowing section and annular guide portion to enhance linear flow and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guide vanes and nose cone are added to generate swirl flow, then surge margin is improved, but intake-air resistance increases and choke flow rate decreases
Solution Approach 1:
The patent removes the nose cone that was previously used to generate swirl flow. Instead, it uses guide vanes arranged in a specific pattern (alternating inclination directions) to generate the necessary swirl flow without the additional resistance caused by the nose cone. This extraction of the harmful component (nose cone) while maintaining the useful function (swirl flow generation) resolves the contradiction between improving surge margin and reducing intake-air resistance.
Solution Approach 2:
The guide vanes are designed with local quality variations - they are arranged to incline alternately in different directions (first and second directions) at different angular positions around the impeller wheel. This localized variation in vane orientation creates the necessary swirl flow pattern without requiring a uniform structure like the nose cone, thereby reducing overall intake-air resistance while maintaining surge margin improvement.
2Reliability
If recirculation channel is added to improve surge phenomenon, then surge limit is improved, but device complexity increases
Solution Approach 1:
The recirculation channel is integrated with the existing housing structure of the centrifugal compressor. The channel uses the housing's inner wall as part of its boundary and connects to existing flow paths, merging the recirculation function with the overall compressor structure rather than adding a completely separate system. This reduces the additional complexity while achieving surge limit improvement.
Solution Approach 2:
The recirculation channel serves multiple functions: it recirculates intake air to improve surge margin, and its structure is integrated with the housing that also serves as the main structural support and flow path containment. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity.
3Reliability
If guide vanes are arranged to generate swirl flow, then surge margin is improved, but manufacturing precision requirements increase
Solution Approach 1:
The guide vanes are segmented into multiple discrete elements arranged around the impeller wheel, with each vane independently oriented in specific directions (first and second directions). This segmentation allows for modular manufacturing and assembly, where each vane can be produced and positioned separately according to predefined angular positions, reducing the overall manufacturing precision requirements compared to a monolithic swirl-generating structure.
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
This design improves the surge margin and choke flow rate, widening the operational range of the compressor while minimizing intake-air resistance and turbulence, thereby enhancing compression efficiency and reducing production costs and assembly complexity.
Implementation Method 1
The guide vanes 114 generate a preceding swirl in the intake air flowing through the inducer 110.
Implementation Method 2
a centrifugal compressor including an impeller wheel rotated by a rotation shaft
Implementation Method 3
The recirculation flow channel recirculates a part of the intake air sucked into the impeller wheel to an intake channel at the upstream of the impeller upstream edge
Implementation Method 4
a centrifugal compressor including an impeller wheel rotated by a rotation shaft
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A centrifugal compressor includes: a compressor housing 15; an impeller wheel 7 for compressing intake air, disposed inside the compressor housing; a parallel flow generating unit 51 for rectifying the intake air flowing in via an intake port 23 to be parallel to the direction of a rotation shaft 9; and a recirculation channel 41 for returning a part of the intake air in an outer circumferential section of the impeller wheel to an upstream side of the impeller wheel 7. The parallel flow generating unit 51 includes a parallel flow generating part 52 including a plurality of guide vanes 55 and a central intake-air flowing section 59 which is a space surrounded by the parallel flow generating part 52. An intake-air outflow direction from an upstream opening 45 is oriented toward the parallel flow generating part 52.