Compact Diagonal Fan Guide Vane Design for Axial Length Optimization
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Solution Overview
Problem
Diagonal fans face challenges with high exit losses due to small blow-out areas and high dynamic pressure, while axial fans require significant axial space, making them inefficient for applications with high air performance and limited installation space.
Innovation Solution
A compact diagonal fan design featuring a guide device with a predetermined blow-out diameter and a small overall axial length, where the diagonal flow is deflected into an axial direction by the housing and evened out by a follower device with guide vanes, optimizing pressure increase and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the discharge diameter B is reduced to compact the fan axially, then the axial length E decreases, but the discharge losses increase due to high dynamic pressure
Solution Approach 1:
The patent optimizes the ratio between axial length E and discharge diameter B within the range 0.3≤E/B≤0.6, and the ratio between discharge diameter B and intake diameter A within 0.70≤A/B≤0.95. These parameter changes allow the fan to achieve compact axial dimensions while maintaining sufficient discharge area to minimize energy losses from high dynamic pressure.
2Object-affected harmful factors
If the intake diameter A is increased to reduce radial deflection, then the radial outer region flow deflection decreases, but the guide device axial length must increase
Solution Approach 1:
The patent specifies that the ratio of intake diameter A to discharge diameter B should be 0.70≤A/B≤0.95. This parameter optimization allows the intake diameter to be sufficiently large to reduce radial deflection in the radial outer region, while the guide device axial extension C is constrained to 0.30≤C/D≤0.75 of the impeller width D, achieving a balance between flow deflection reduction and compact axial dimensions.
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 a high throw distance with a compact axial design, improving pressure increase and efficiency while reducing radial deflection and axial space requirements.
Implementation Method 1
The diagonal flow generated by the diagonal impeller during operation is deflected into an axial flow direction by an inner wall of the housing. Viewed in the axial flow direction, a guide vane device with a plurality of circumferentially distributed guide vanes is arranged downstream of the diagonal impeller, which guide vanes even out the air flow generated by the diagonal impeller.
Data Source
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AI summary
The invention relates to a diagonal fan comprising an electric motor, a housing, and a diagonal impeller which is received within the housing, can be driven via the electric motor, and generates a diagonal flow during operation that is deflected in an axial flow direction by an inner wall of the housing. An outlet guide vane device with a plurality of guide vanes, which are distributed in the circumferential direction, is arranged adjacently to the diagonal impeller when viewed in the axial flow direction, and the outlet guide vane device homogenizes an airflow generated by the diagonal impeller and has an air outlet with a specified outlet diameter B, wherein the diagonal fan extends over a total axial length E, and the ratio of the total axial length E to the outlet diameter B is configured such that 0.3≤E/B≤0.6.