Inducer Fan Assembly With Offset Collector for Low-Noise Combustion
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Solution Overview
Problem
Existing inducer fan assemblies in gas furnace systems face challenges in achieving efficient combustion performance and overcoming flow losses while maintaining a compact form factor and reducing noise levels.
Innovation Solution
The inducer fan assembly features a toroidal collector with a central recessed zone and a fan rotor with blades of varying heights, arranged radially outward and axially offset from the hub, along with an inlet casing piece matching the blade tip revolved contour, which allows for efficient airflow and reduced noise through a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a traditional inducer fan assembly design is used, then the structure is simpler, but the noise level increases due to unsteady interactions and the profile height increases
Solution Approach 1:
The inducer housing is segmented into a collector section and a discharge section that can be independently optimized. The collector section is positioned to be radially outward and axially offset from the fan rotor hub, creating distinct flow zones that reduce unsteady interactions and noise while maintaining structural integrity
Solution Approach 2:
The collector is positioned in a different spatial arrangement (radially outward and axially offset) from the fan rotor hub, utilizing three-dimensional space optimization to reduce noise-generating interactions while maintaining a compact overall profile
2Productivity
If the collector is positioned closer to the fan rotor hub, then the profile is more compact, but flow losses increase and combustion performance deteriorates
Solution Approach 1:
The inducer housing provides localized flow management with the collector section positioned optimally relative to the fan rotor. This localized structural arrangement improves flow characteristics and combustion performance without requiring a proportional increase in overall profile height
Solution Approach 2:
The collector section is pre-positioned to optimize flow capture from the fan rotor before discharge. This preliminary flow management arrangement enhances combustion performance while maintaining a compact profile by establishing optimal flow paths in advance
3Object-affected harmful factors
If the inlet casing contour does not match the blade tip revolved contour, then manufacturing is simpler, but airflow efficiency decreases and noise increases
Solution Approach 1:
The inlet casing contour is designed to match the blade tip revolved contour, creating smooth curved surfaces that guide airflow efficiently. This curved geometry reduces turbulence and noise while the matching contours can be achieved through standard manufacturing processes
Solution Approach 2:
The inlet casing contour is created as a copy of the blade tip revolved contour, ensuring geometric compatibility for optimal airflow. This copying approach maintains manufacturing simplicity by using the existing blade geometry as the template for the inlet casing shape
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 configuration enhances combustion performance by managing airflow effectively, reduces noise through minimized unsteady interactions, and enables more flexible furnace configurations with a lower profile, resulting in improved operational efficiency and quieter operation.
Implementation Method 1
a centrifugal fan rotor driven by the motor shaft
Data Source
AI summary
An inducer fan assembly includes a flow collector piece having a motor support surface, a toroidal collector, and a discharge region extending tangentially from the collector. A fan rotor is rotatably mounted relative to the motor support surface. The fan rotor includes a hub surface, and an outer circumferential edge. The fan rotor further includes a plurality of blades that extend from the hub surface. The plurality of blades extend from a leading edge to a trailing edge that extends beyond the outer circumferential edge. The plurality of blades include a first height and a second height that define a blade tip revolved contour. The collector is arranged radially outward from and axially off-set from the hub surface. An inlet casing piece is mounted to the flow collector piece. The inlet casing piece includes a contour that is substantially similar to the blade tip revolved contour of the fan rotor.