Curved Sidewall Diffuser for Laminar Airstream
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Solution Overview
Problem
HVAC systems face energy losses and inefficiencies due to adverse flow structures caused by non-ideal expansion of airstreams, which results in increased pressure and recirculation, especially when traditional diffusers with inclined walls are used, leading to separation and turbulence.
Innovation Solution
A diffuser with a curved sidewall that gradually increases the cross-sectional area and redirects the airstream, maintaining laminar flow and constant pressure, thereby minimizing separation and adverse flow structures by using a convex portion near the inlet and a concave portion near the outlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional diffusers use an inclined wall to gradually change the cross-sectional area, then the expansion is optimized, but the airstream separates from the inclined wall causing vacuum pockets and unfavorable flow structures
Solution Approach 1:
The patent applies curvature by replacing the traditional inclined wall with a curved surface that follows the natural flow lines of the airstream. The curved surface is defined by a curve having a first portion, second portion, and third portion that smoothly guide the air, preventing separation and eliminating vacuum pockets while maintaining gradual area expansion.
2Area of stationary object
If the cross-sectional area of the airstream increases, then the expansion function is achieved, but the velocity decreases causing increased pressure and adverse flow structures
Solution Approach 1:
The patent applies preliminary action by curving the surface in advance to guide the airstream smoothly through the expansion zone. The curve is specifically designed with portions that anticipate and prevent flow separation before it can occur, maintaining laminar flow and reducing energy losses during the area expansion process.
3Adaptability or versatility
If the direction of the airstream is changed at the same location as a change in cross-sectional area, then space utilization is improved, but the airstream separates from the wall generating unfavorable flow structures
Solution Approach 1:
The patent merges the direction change function with the cross-sectional area expansion function into a single curved surface. The curve simultaneously achieves both the area increase and the flow direction change, allowing space utilization improvement while preventing flow separation through the smooth curvature that guides the airstream through both transitions.
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 diffuser design enhances airflow efficiency by maintaining laminar flow and reducing unfavorable flow structures, ensuring a smooth transition in both cross-sectional area and direction without significant pressure variations, thus improving HVAC system performance.
Implementation Method 1
maintaining laminar flow and constant pressure
Implementation Method 2
The separation of the airstream from a traditional diffuser wall causes unfavorable flow structures
Data Source
AI summary
In one aspect, a diffuser for expanding the cross-sectional area of an airstream comprises an inlet comprising an inlet cross-sectional area and an outlet comprising an outlet cross-sectional area. The outlet cross-sectional area is greater than the inlet cross-sectional area. A curved sidewall extends from the inlet to the outlet and at least partially defines an inner passageway. The curved sidewall comprises a convex portion and a concave portion. The convex portion is adjacent the inlet and the concave portion is adjacent the outlet.