Air Handling Unit Stator Ring Design to Reduce Turbulence and Noise
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Solution Overview
Problem
Existing Air Handling Units (AHUs) and fans in HVAC systems generate noise across various fan speeds, particularly at resonance frequencies, and current noise reduction methods, such as sound-absorbing materials, do not adequately address noise issues at all operational speeds.
Innovation Solution
The design incorporates a stator ring with a curved surface that guides air flow from radial to axial, reducing recirculation and turbulence, and is integrated with a flow guiding body to minimize noise and energy losses across all fan speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sound absorbing material is provided in the AHU and air ducts, then noise level is reduced, but energy losses and recirculation are not adequately addressed
Solution Approach 1:
The stator disc features a curved surface geometry that guides air flow smoothly from radial to axial direction. This curvature design minimizes turbulence and recirculation zones, reducing energy losses while also lowering noise generation from chaotic flow patterns
Solution Approach 2:
The stator disc acts as an intermediary component between the fan blades and the downstream air ducting. It mediates the transition of air flow from radial to axial direction, controlling the flow transformation to minimize turbulence and energy dissipation
2Productivity
If fan speed is increased to provide higher airflow, then productivity increases, but noise level increases due to resonance at certain speeds
Solution Approach 1:
The curved stator disc surface creates a streamlined flow path that remains effective across varying fan speeds. By maintaining smooth flow guidance regardless of rotational velocity, it reduces turbulence-induced noise even at high airflow rates where resonance problems typically occur
Solution Approach 2:
The stator disc modifies the flow parameters (direction and velocity distribution) of air leaving the fan blades. This parameter transformation optimizes the flow field structure across different operating conditions, reducing noise generation mechanism
3Loss of energy
If a stator disc with curved surface is added to guide air flow, then energy losses and noise are reduced, but device complexity increases
Solution Approach 1:
The stator disc is integrated with the fan assembly as a unified component structure. The curved surface is formed as part of the stator disc itself rather than as a separate complex flow guidance system, simplifying the overall device while achieving the desired flow control
Solution Approach 2:
The stator disc performs multiple functions: it serves as a structural support element, a flow guidance component, and a turbulence reduction device. This multi-functionality eliminates the need for additional separate components, maintaining device simplicity while achieving energy loss reduction
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 significantly reduces noise levels and energy losses by minimizing recirculation and turbulence, providing a more efficient and quieter operation of the AHU across a range of fan speeds.
Implementation Method 1
The surface of the stator ring is bent backwards so as to provide a flow guide for the radial flow from the fan when the air flow deflects and changes direction from being a mainly radial flow to a mainly axial flow
Implementation Method 2
This will reduce the recirculation and turbulence downstream of the fan, which reduce the noise level and energy losses
Data Source
AI summary
An AHU includes air channels. The air channel includes an air inlet and outlet guiding supply air into a building from outside or extract air from a building to the outside. The AHU is connected to an air ventilation ducting system. The AHU further includes a fan inducing a flow in the system when connected thereto. The fan provides a radial flow or mixed flow. The flow from the fan is redirected from radial flow to axial flow on its way from the inlet to the outlet. To provide a more efficient flow when the air flow from the fan changes direction, the fan includes a stator ring. The stator ring has an inner circumference encircling the fan's back plate and a surface essentially levelled with the surface at the edge of the back plate. The AHU may also include a flow guiding body guiding the air further downstream.