Fan Housing Guide Elements Reduce Leakage Flow
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Solution Overview
Problem
Axial or diagonal fans face inefficiencies due to head gap leakage flows and backflow, which reduce static efficiency and increase noise.
Innovation Solution
The introduction of individual, free-standing guide elements on the inner wall of the fan housing, designed to stabilize and redirect the swirling flow, counteracting backflow and flow separations, and integrated into the housing using injection molding or metal casting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the radial gap between the impeller and casing is reduced to minimize head gap leakage, then leakage flow is reduced, but the impeller cannot be properly mounted or maintained
Solution Approach 1:
The patent introduces individual freestanding guide elements that are segmented from the main casing structure. These elements are positioned in the radial gap area to control leakage flow without requiring the entire casing-impeller interface to be tightly sealed, thus maintaining accessibility for impeller mounting and maintenance while reducing energy loss through localized flow control.
Solution Approach 2:
The freestanding guide elements act as intermediary structures between the impeller and the casing. They mediate the flow in the radial gap area, controlling the leakage flow path without requiring direct contact or tight clearance between the impeller and casing, thus solving both the leakage reduction and accessibility requirements.
2Loss of energy
If downstream diffusers are used to improve flow recovery, then static efficiency increases, but blockage effects and backflow areas increase
Solution Approach 1:
The freestanding guide elements are positioned upstream in the radial gap area before the flow enters the diffuser section. They perform preliminary flow conditioning by controlling and directing the leakage flow, which prevents the formation of large backflow areas and blockage effects in the downstream diffuser, allowing the diffuser to maintain high static efficiency without harmful backflow.
Solution Approach 2:
The guide elements create localized flow control in specific areas of the radial gap, directing flow in a way that prevents large-scale backflow regions. This local flow management allows the downstream diffuser to operate efficiently without being affected by upstream backflow problems.
3Stability of the object's composition
If a guide device is integrated into the housing to stabilize flow, then flow stability improves, but manufacturing complexity and noise from additional components increase
Solution Approach 1:
Instead of integrating a complex unified guide device into the housing, the patent uses multiple simple freestanding guide elements that are segmented and positioned independently in the radial gap area. This segmentation achieves flow stabilization through distributed simple structures rather than a single complex integrated component, reducing manufacturing complexity and potential noise sources.
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 solution enhances the fan's efficiency and reduces noise by effectively stabilizing the flow and preventing backflow, thereby improving the performance of the fan and its integrated diffuser.
Implementation Method 1
flow separation on the inner casing wall in the area of the impeller and downstream thereof
Implementation Method 2
The inner guide vanes 3 stabilize the swirling flow near the axis exiting the impeller by reducing the swirl in the flow
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A housing for a fan, preferably for an axial or diagonal fan, wherein the fan comprises an impeller wheel and at least one throughflow region, is characterized in that a plurality of individual, freestanding guide elements are provided immediately downstream of the impeller wheel or of the blades of the impeller wheel in an outer region of the housing and therefore in the throughflow region. A fan comprises a corresponding housing.