雨刷流場數值分析與優化

Numerical Analysis and Optimization of Wiper Flow Field

張宸瑋(Chang Chen-wei)

指導教授 ： 蔡建雄 ； 曾全佑

國立屏東科技大學/工學院/車輛工程系所/碩士(2021年)

https://doi.org/10.6346/NPUST202100453

摘要

車輛高速行駛時，因空氣動力影響，氣流沿著引擎蓋吹向擋風玻璃跟雨刷，並對雨刷造成升力和阻力，可能導致雨刷在高速時行駛時，會有漏刮的現象。本研究使用ANSYS FLUENT軟體，對雨刷進行CFD模擬，分析結果發現擺放角度30度和80度時，平面和雨刷放置車上擋風玻璃時趨勢相近，未來在模擬時可簡化為平面流場預測各部件升阻力。利用Adjoint Solver優化模組對雨刷與雨刷臂進行優化，並以降低升力為優化目標，模擬結果顯示: 改變雨刷臂之迎風面角度，讓雨刷臂有更多向下壓的力，能有效降低升力；最後將優化的雨刷與雨刷臂組件放在車上玻璃作CFD分析，結果顯示較原始設計的雨刷組件，雨刷刮片上升力減少了69%，阻力增加17%，雨刷臂和原模型升力減少41%，阻力增加5%。雖然升力都能有效降低，但阻力變大，因此在設計時須考量雨刷馬達效能是否能克服阻力。

關鍵字

雨刷 ； 空氣動力 ； 升力 ； 阻力 ； 優化

並列摘要

When the vehicle is running at high speed, the air flows along the engine hood to the windshield and the wiper, and induce lift force and drag force of the wiper, which may result in the wiper to lift off the windshield and destroy the wiping performance. This study uses ANSYS FLUENT software to perform CFD simulation on the wiper. The analysis results show that when the windshield of the car is placed on the windshield of the plane and the wiper when placed at an angle of 30 degrees and 80 degrees, the trend is similar. In the future, the simulation can be simplified to a plane flow field prediction. Besides, this study uses the Adjoint Solver optimization module to optimize the shape of the wiper and wiper arm, and reduce the lift as the optimization goal. The simulation results show that changing the angle of the windward side of the wiper arm allows the wiper arm to have more downward pressure, which can effectively reduce the lift. Finally, the optimized wiper and wiper arm assembly is placed on the windshield of the car for CFD analysis. The results show that comparing with the original design of the wiper assembly, the lift force of the wiper blade is reduced by 69%, the drag force is increased by 17%, the lift force of the wiper arm is reduced by 41%, and t the drag force is increased by 5%. Although the lift can be effectively reduced, the resistance becomes larger, so it is necessary to consider whether the efficiency of the wiper motor can overcome the resistance in the design stage.

並列關鍵字

Wiper ； aerodynamic ； lift force ； drag force ； optimization

參考文獻

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