Inlet Guide Vane Trailing-Edge Shape for Karman Vortex Suppression
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Solution Overview
Problem
The generation of Karman vortices in centrifugal compressors due to fluid flow through inlet guide vanes leads to pressure loss, noise, and vibrations, which adversely affect the performance of the rotary machine.
Innovation Solution
The inlet guide vane is designed with movable blades that include a first and second blade surface and an inclined surface at the trailing edge, forming an asymmetrical shape to suppress Karman vortex generation, and are rotatable about a radial center axis to adjust fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple plate portion with bent portion is used for inlet guide vane, then manufacturing is easy and structure is simple, but Karman vortex is generated causing pressure loss and noise
Solution Approach 1:
The blade cross-section is designed with an inclined surface at the trailing end that is asymmetric in shape. This inclined surface is formed at an angle of 5 to 30 degrees relative to the blade surface, creating an asymmetric geometry that prevents the formation of Karman vortices while maintaining manufacturing feasibility through standard machining processes.
2Object-generated harmful factors
If inclined surface is added to blade trailing end, then Karman vortex is suppressed, but blade structure becomes more complex
Solution Approach 1:
The inclined surface is localized only at the trailing end portion of the blade, rather than modifying the entire blade structure. This local modification approach suppresses Karman vortex generation at the critical trailing edge region while keeping the rest of the blade structure simple and maintaining ease of manufacture.
3Adaptability or versatility
If movable blades are used to adjust flow rate, then flow control is improved, but device complexity increases
Solution Approach 1:
The inlet guide vane employs movable blades that can rotate about a radial axis to adjust the flow rate. This dynamic configuration allows the blade angle to be changed according to operating conditions, providing flow control capability. The movable structure is supported by a simple radial axis mechanism that does not significantly increase overall device 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 effectively reduces Karman vortex generation, improves opening-degree characteristics, and enhances compressor performance by minimizing fluid leakage and separation, while maintaining high workability and efficiency.
Implementation Method 1
a Karman vortex may be generated on the downstream side relative to the movable blades. When a Karman vortex is generated, the flow of the fluid having passed through the inlet guide vane is disturbed
Data Source
AI summary
An inlet guide vane according to the disclosure includes a plurality of movable blades disposed at intervals in a circumferential direction of a rotor shaft and rotatable about a center axis extending in a radial direction of the rotor shaft. Each of the movable blades includes a first blade surface and a second blade surface extending in a direction connecting a leading edge and a trailing edge, and an inclined surface formed at a trailing end including the trailing edge and extending obliquely from the first blade surface to the second blade surface when viewed from the radial direction. The inclined surface is a flat surface whose cross-sectional shape viewed from the radial direction is inclined so as to be connected, at an acute angle, to the second blade surface at the trailing edge.