Air Flow Measuring Device with Single-Cross Straightening Grid
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Solution Overview
Problem
Existing air flow measuring devices with multiple crossing regions in straightening grids experience increased pressure loss and turbulent flow, leading to signal fluctuations and uneven flow speed, which affect the accuracy of air flow measurements.
Innovation Solution
An air flow measuring device with a straightening grid having only one crossing region and a mesh member between the straightening grid and the air flow meter, which stabilizes the air flow and reduces pressure loss and signal fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a straightening grid with many cross shapes is used, then the flow straightening effect is improved, but the pressure loss increases
Solution Approach 1:
The invention divides the straightening grid into multiple sections along the flow direction, with each section containing fewer cross shapes. This segmentation reduces the total number of crosses while maintaining the flow straightening effect, thereby reducing pressure loss.
Solution Approach 2:
The invention applies different densities of cross shapes to different sections of the straightening grid. The upstream section has fewer crosses to reduce pressure loss, while downstream sections have progressively more crosses to achieve the desired flow straightening effect, creating a gradient distribution that optimizes both pressure loss and flow quality.
2Stability of the object's composition
If a straightening grid with many cross shapes is used, then the flow straightening effect is improved, but turbulent flow increases causing signal fluctuation
Solution Approach 1:
By segmenting the straightening grid into multiple sections with increasing numbers of crosses from upstream to downstream, the invention avoids creating a large number of crosses in one location, thereby reducing intense turbulent flow and signal fluctuation while still achieving flow straightening.
Solution Approach 2:
The gradient distribution of cross shapes creates local variations in flow straightening intensity, preventing the formation of strong turbulent flows that would occur with a uniform high-density cross distribution, thus reducing signal fluctuation.
3Stability of the object's composition
If a straightening grid with many cross shapes is used, then the flow straightening effect is improved, but the flow speed deviation cannot be averaged
Solution Approach 1:
The segmented structure with multiple sections allows progressive averaging of flow speed deviations. Each section contributes to gradually equalizing the flow velocity distribution, resulting in better flow uniformity at the measurement location compared to a single-section grid.
Solution Approach 2:
The varying density of crosses in different sections creates local flow adjustments that collectively average out flow speed deviations, improving the uniformity of flow velocity at the air flow meter location.
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 solution effectively stabilizes air flow, reduces pressure loss, and minimizes signal fluctuations, resulting in more accurate air flow measurements by straightening swirl flows into linear flows and averaging flow speed unevenness.
Implementation Method 1
a straightening plate 4 having only one crossing region α and straightens a flow of air toward the AFM 3 through the straightening plate 4 by means of a mesh member 6
Implementation Method 2
The mesh member 6 having a reticulated shape is disposed between the straightening plate 4 and the AFM 3. Consequently, the flow speed unevenness can be averaged, and the output of the AFM 3 can be stabilized
Data Source
AI summary
An air flow measuring device includes an air flow meter (AFM), a straightening grid, and a mesh member. The AFM includes an air inlet and is configured to measure a flow rate of air flowing into the air inlet. The straightening grid includes a straightening plate having only one crossing region and is disposed on an upstream side of the AFM in a flow direction of air to straighten a flow of air toward the AFM through the straightening plate. The mesh member is formed in a netted manner and is disposed between the straightening plate and the AFM.