Automotive Fan Blade Chord Optimization for Flow
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Solution Overview
Problem
Propellers used in vehicles with internal combustion engines face challenges in achieving high flow rates while maintaining efficiency and uniform pressure distribution, leading to inefficiencies and reduced performance, especially at high flow rates due to uneven aerodynamic loading and secondary flows.
Innovation Solution
The design incorporates blades with a chord length at least 1.5 times the shortest chord length over the last 20% of the span, along with a back bend in the mid-chord line and significant camber, optimizing aerodynamics and filling the vein effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large-span blades are used to achieve high flow rates, then flow rate increases, but pressure distribution becomes non-uniform and efficiency decreases
Solution Approach 1:
The patent applies local quality by varying the chord length along the blade span, specifically making the chord length in the last 20% of the span at least 1.5 times the shortest chord length. This local modification optimizes the aerodynamic loading distribution in the critical outer region of the blade, ensuring more uniform pressure distribution while maintaining high flow rates.
2Reliability
If blade chord length is increased in the last 20% of span, then aerodynamic efficiency improves, but blade complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the chord length parameter along the blade span. Specifically, the chord length in the last 20% of the span is increased to be at least 1.5 times the shortest chord length, which optimizes aerodynamic efficiency without requiring complex blade designs.
3Productivity
If high flow rates are achieved, then ventilation performance improves, but secondary flows and recirculations increase
Solution Approach 1:
The patent addresses secondary flows and recirculations by applying local quality optimization to the blade geometry. The increased chord length in the last 20% of the span creates more favorable aerodynamic conditions in the outer blade region, reducing adverse pressure gradients and minimizing secondary flows and recirculations that cause energy losses.
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 the propeller's ability to maintain high flow rates with improved efficiency and uniform pressure distribution, even at high flow rates, reducing recirculations and increasing the work delivered by the propeller.
Implementation Method 1
The evolution of the chord to a great length over the last twenty percent of its span makes it possible to produce ventilation propellers which are optimized for aerodynamics and, among other things, for an effective filling of the vein at the head
Data Source
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AI summary
The invention relates to a ventilation propeller (1) comprising a hub (2) and blades (3) extending radially outwards from the hub (2) between a blade root (3a) and a blade tip (3b), which is characterized in that said blades (3) have, in the last twenty percent of their span, at least one chord whose length is at least equal to 1.5 times the shortest chord length over the entire span of the blade. Advantageously, the blade has, in said last twenty percent of the span, at least a portion of its mid-chord line having a trailing curvature and a pitch that varies by at least +5°.