Axial Fan Housing Geometry for Reduced Blade Tip Air Bypass
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Solution Overview
Problem
Existing axial fans in HVAC systems suffer from reduced flow rates and increased power consumption due to wide clearances between blade tips and the housing, leading to inefficient air bypass and noise generation.
Innovation Solution
An axial fan assembly with a housing design that increases the inner diameter of the housing near the blade tips to accommodate longer blades, reducing air bypass and improving airflow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If axial fan blades are fabricated using injection molding process, then manufacturing ease is improved, but manufacturing precision deteriorates resulting in wide clearance between blade tips and housing
Solution Approach 1:
The housing includes a first portion with a first inner diameter and a second portion with a second inner diameter that is less than the first inner diameter. The second portion is positioned proximate the rotational travel path of the blade tips to reduce clearance locally where it is most needed, while maintaining a larger clearance in other areas for manufacturing ease and airflow.
2Ease of operation
If wide clearance is maintained between blade tips and housing, then ease of assembly is improved, but productivity deteriorates due to reduced flow rate
Solution Approach 1:
The housing features a variable inner diameter with a first portion having a larger diameter for ease of assembly and a second portion having a smaller diameter proximate the blade tips to reduce air bypass and improve flow rate. This localized modification addresses the productivity issue without compromising overall assembly ease.
3Device complexity
If wide clearance is maintained between blade tips and housing, then device complexity is reduced, but loss of energy increases due to air bypass around blade tips
Solution Approach 1:
The housing includes a second portion with a reduced inner diameter positioned specifically proximate the rotational travel path of the blade tips. This localized geometric modification reduces air bypass and energy loss without requiring complex additional components or systems.
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
Enhances airflow rate and reduces power consumption by minimizing air bypass, thereby optimizing HVAC system performance.
Implementation Method 1
The axial fan includes a hub and one or more blades extending radially from a center point of the hub about which the axial fan rotates
Data Source
AI summary
An axial fan assembly for use with an HVAC system, including an axial fan and a housing. The axial fan includes a hub and one or more blades extending a blade length out to a blade tip. The hub is configured to rotate the blade tip of each of the one or more blades along a rotational travel path. The housing includes an inner surface radially outwards of the rotational travel path of the blade tip of the one or more blades, the inner surface having an inner diameter, and a housing portion proximate the rotational travel path of the blade tip of the one or more blades, the inner surface within the housing portion having an extended inner diameter to accommodate the blade length of the one or more blades and reduce a flow of air bypassing the one or more blades.