Centrifugal Compressor Reverse Swirl Fixed Blades
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Solution Overview
Problem
Conventional centrifugal compressors face efficiency degradation and increased size due to complex mechanisms for guide vanes, leading to reduced operating ranges and pressure losses at both low and high flow rates, especially when using recirculation and swirling flow techniques.
Innovation Solution
A centrifugal compressor design incorporating a reverse swirling flow generation unit with fixed blades and a recirculation flow path, generating a swirling flow opposite to the impeller's rotation direction, which increases the operating range without the need for a movable guide vane mechanism, improving efficiency and reducing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If guide vanes are provided to generate swirling flow of intake air, then the operating range is increased, but the device complexity and size increase
Solution Approach 1:
Instead of generating swirling flow in the same direction as impeller rotation (conventional approach), the patent generates swirling flow in the opposite direction using guide vanes. This reverse swirling flow prevents impeller leading edge separation at small flow rates while maintaining a simple fixed vane structure without complex mechanisms
Solution Approach 2:
The patent extracts only the essential function of guide vanes (generating reverse swirling flow) and removes the complex movable mechanisms. The guide vanes are configured as fixed structures with specific angular orientations that directly generate the required reverse swirl, eliminating the need for adjustable mechanisms
2Adaptability or versatility
If recirculation flow path is provided to prevent impeller leading edge separation, then the operating range is increased, but the efficiency degrades due to pressure loss
Solution Approach 1:
The recirculation flow path is configured to preliminarily mix recirculated air with fresh intake air before the combined flow enters the impeller. This preliminary mixing occurs in a diffusion section where the flow is gently guided, minimizing pressure loss while ensuring the recirculated flow reaches the impeller leading edge to prevent separation
3Adaptability or versatility
If both guide vanes and recirculation flow path are combined, then the operating range is increased, but the device complexity increases
Solution Approach 1:
The patent merges the guide vane structure with the recirculation flow path into an integrated design. The guide vanes are positioned within the housing to simultaneously generate reverse swirling flow and guide both fresh and recirculated air streams into the impeller, eliminating the need for separate mechanisms and reducing overall 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 design achieves stable operation across a wide range of flow rates with improved pressure ratios and efficiency, overcoming the limitations of complex mechanisms and size issues in existing technologies.
Implementation Method 1
generates a swirling flow of the intake gas, flowed in through the air intake port, in a direction opposite to a rotation direction of the impeller
Implementation Method 2
compresses intake gas flowed in through the air intake port, the impeller being rotatable about the rotational shaft
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
Provided is a centrifugal compressor which can be stably operated in a wide range by increasing an operating range on a low-flow-rate side and on a high-flow-rate side, with a simple structure of combining a recirculation flow path and a reverse swirling flow generation unit including fixed blades, without providing a complicated movable mechanism for a guide vane. A compressor 3 includes: a compressor casing 9 including an air intake port 13 open in a direction of a rotational shaft 5 of the compressor 3 and an air intake path 11 connected to the air intake port 13, an impeller 7 which is disposed rotatable about the rotational shaft 5 and compresses intake gas flowed in through the air intake port 13, a reverse swirling flow generation unit 41 which generates a swirling flow of the intake gas, flowed in through the air intake port 13, in a direction opposite to a rotation direction of the impeller 7, and a recirculation flow path 25 which communicates between an outer periphery of the impeller 7 with the air intake path 11 on an upstream side of the impeller 7. The reverse swirling flow generation unit 41 includes reverse swirling fixed blades 43 which generates a swirling flow at a predetermined angle with respect to the direction opposite to the rotation direction of the impeller 7.