Intermediate Shroud Axial Fan Structure for Blade Flutter Control
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Solution Overview
Problem
Existing axial fan assemblies with minimized blade thickness and complex curves are prone to blade flexure and flutter due to significant size and vibration, leading to decreased stability and airflow efficiency.
Innovation Solution
Incorporating an intermediate shroud with a circumferential sinusoidal shape proximate to the blade tip to provide structural support and reduce vibration, enhancing stability and airflow performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blade thickness is minimized and complex curves are used to improve performance, then airflow efficiency is improved, but blade stability deteriorates due to increased flexure and flutter
Solution Approach 1:
An intermediate shroud is introduced as a mediator component positioned between the blade and the fan housing. This shroud acts as a structural intermediary that provides support to the blade, reducing flexure and flutter while allowing the blade to maintain its optimized thin profile and complex curvature for improved airflow efficiency.
Solution Approach 2:
The intermediate shroud provides localized structural support at specific critical areas of the blade, particularly near the blade root and along the blade span where flexure occurs. This localized reinforcement allows the blade to maintain its optimized geometry for performance while having support exactly where needed to prevent instability.
2Productivity
If blade size is increased to improve performance, then airflow capacity is improved, but vibration and flutter increase leading to decreased stability
Solution Approach 1:
The intermediate shroud serves as a damping intermediary that absorbs and dissipates vibration energy generated by larger blades. By positioning this shroud between the blade and housing, it provides a mechanism to reduce harmful vibrations and flutter while allowing the blade to be sized appropriately for improved airflow capacity.
Solution Approach 2:
The intermediate shroud is designed beforehand to provide cushioning and damping against vibrations and flutter that will occur during operation. This preventive measure is built into the structure prior to operation, allowing larger blades to be used for improved capacity without excessive vibration.
3Stability of the object's composition
If intermediate shroud is added to reduce vibration and improve stability, then blade stability is improved, but device complexity increases
Solution Approach 1:
The intermediate shroud is designed to be integrated with existing fan assembly components, merging the vibration damping function with the structural framework of the fan. This integration approach provides the necessary stability improvement while minimizing the increase in overall assembly complexity by utilizing and combining with existing structural elements.
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 intermediate shroud increases blade stability, improves airflow smoothness and flow rate, reduces sound, and extends fatigue life while maintaining balance.
Implementation Method 1
an intermediate shroud positioned proximate to a blade tip of the one or more blades to facilitate damping vibration
Data Source
AI summary
An axial fan assembly includes a hub and one or more blades extending radially from a center point of the hub about which the axial fan rotates relative to an axis of rotation. Each of the one or more blades extending a blade length from the hub to a free edge of the one or more blades. The axial fan assembly also includes an intermediate shroud arranged radially outwards of the hub and radially inwards of the free edge of the one or more blades. The intermediate shroud including a first shroud end, and a second shroud end laterally opposite the first shroud end. Wherein the intermediate shroud has a circumferential sinusoidal shape.