Kitchen Hood Fan Inlet Layout for Lower Head Loss and Noise
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Solution Overview
Problem
Existing kitchen hoods experience high head losses and noise due to the restricted inlet opening and sudden air flow direction changes, which limit their efficiency and performance.
Innovation Solution
The design of the hood features a centrifugal fan with a volute and wheel housed in an enclosure where the first inlet opening is positioned to face a corner, increasing the space in front of the inlet and reducing air speed, thus minimizing head losses and noise. The enclosure's converging walls and strategically placed inlet openings optimize air flow, allowing for a more efficient air intake and expulsion system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the inlet opening of the volute is positioned against the face of the enclosure, then the size of the enclosure is limited, but this generates noise and major head losses due to reduced passage cross-section and sudden change of air flow direction
Solution Approach 1:
The inlet opening is repositioned from a face-parallel position to a corner position, utilizing the third dimension (depth) of the enclosure. This spatial reconfiguration allows the air flow to enter at an angle, creating a more gradual transition and reducing sudden direction changes while maintaining compact enclosure dimensions.
Solution Approach 2:
The corner position of the inlet opening acts as an intermediary zone that mediates between the enclosure walls and the air flow path. This intermediate positioning allows for a smoother flow transition, reducing turbulence and head losses while maintaining the compact enclosure design.
2Volume of moving object
If the inlet opening of the volute is positioned against the face of the enclosure, then the enclosure size is limited, but this generates noise due to reduced passage cross-section and sudden change of air flow direction
Solution Approach 1:
By positioning the inlet opening in the corner (utilizing three-dimensional space) rather than against a face, the air flow path is lengthened and smoothed. This reduces sudden direction changes and turbulence, thereby decreasing noise generation while maintaining compact enclosure size.
Solution Approach 2:
The corner inlet opening serves as an intermediary that creates a gradual transition zone for the air flow. This intermediate positioning reduces abrupt flow direction changes and turbulence, which are the primary sources of noise, while preserving the compact enclosure design.
3Loss of energy
If the inlet opening is positioned to face a corner, then the space in front of the inlet is increased reducing air speed and head losses, but the enclosure requires optimized wall configuration
Solution Approach 1:
The inlet opening is positioned in the corner, utilizing the third dimension to create additional space in front of the inlet. This spatial arrangement naturally reduces air speed and head losses without requiring complex internal flow control structures, achieving energy efficiency through geometric optimization.
Solution Approach 2:
The corner positioning creates an asymmetric flow pattern that is optimized for reduced head losses. The converging walls are configured asymmetrically to match the corner inlet position, creating a streamlined flow path that reduces turbulence and energy losses while maintaining structural simplicity.
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 design enhances air flow efficiency by reducing head losses and noise, enabling the selection of a more optimized electric motor and improving overall hood performance.
Implementation Method 1
a centrifugal fan comprising a volute 21 and a wheel 22 positioned inside the volute 21, the wheel 22 having an axis 220 of rotation
Data Source
Figure 1
Figure 2
AI summary
Described is a hood for a domestic kitchen comprising: - a centrifugal fan (2) comprising a volute (21) and a wheel (22) positioned inside the volute (21), the wheel (22) having an axis (220) of rotation; the volute (21) comprising a first inlet opening (210) allowing entry of air inside the volute (21); the volute (21) comprising a first and a second side (211, 212) extending transversally to a direction identified by the axis (220) of rotation; the first side (211) circumscribing the first inlet opening (210); - an enclosure (3) housing at least a part of the volute (21) and the wheel (22). The enclosure (3) comprises a first and a second wall (51, 52) reciprocally convergent and connecting in a first zone (30) of reciprocal connection, the first and the second wall (51, 52) not being coplanar. At least a part of the first wall (51) of the volute (21) faces the first connection zone (30).