扭力轉換器的扁平化設計以減少體積及重量但同時又保有高效率是車輛工業的努力方向，本研究參考Jandasek (1961)所做的外型及操作條件為基礎，計算其流場、性能並與其實驗結果做比對，並以此基礎再將扭力轉換器在各層葉片入出口角不變的情況下將扭力轉換器沿著軸向做雙邊與單邊20%的扁平化，探討流場與性能上的差異，了解扁平化設計的優缺點及物理特性，進而作為未來設計扭力轉換器的參考依據。本研究利用CFD方法模擬扭力轉換器三維流場進行數值模擬研究，數值方法採用有限體積法求解三維Reynolds-Averaged Navier-Stokes方程式，配合k-ε紊流模型與非結構性網格，計算不同轉速比下的扭力比、效率與流場特性。首先在原外形的模擬結果符合文獻實驗數據，驗證了模擬的準確性。扁平化的分析結果顯示，扭力轉換器的元件在沿軸向扁平化後將使該元件葉片壓力面與吸力面間的壓差增加而提升扭力，而單邊扁平在扭力比與效率的提升上較雙邊扁平來得有優勢，能在不犧牲整體性能的前提下縮小體積。未來可藉由對流場的了解進而做葉片角度的變更，使扁平化設計的效率能夠提升。

Squashing design of torque converter is the striving way of vehicle industry to reduce the volume and weight and it can also maintain high efficiency. This research consults the profile and condition of Jandasek’s (1961) work, calculates the flow-field and performance and then compares the results with the experiment for verification. The torque converter is squashed by 20% bilaterally and unilaterally in axial direction under the same blade angle to investigate the difference of flow-field and performance. Thus, major advantages and physical characteristic of squashing design are obtained. The above study can be a refer-ence for future design. To understand the inner flow-field of three blade sets, this research simulates the 3-D flow-field and calculates the performance under different speed ratio by using CFD method, solving Reynolds-Averaged Navier-Stokes equation numerically with finite volume method and involving the k-ε turbulence model and unstructured grid. The simulation result of the original profile matches satisfyingly with the experiment. The analysis result of squashing design reveals that the pressure difference between pressure side and suction side gets higher after the squashing and then the torque of blade is in-creased. The unilateral squashing type is better than bilateral squashing type on increasing the torque ratio and efficiency. It can reduce the volume and will not sacrifice the perfor-mance. According to our realization about the flow-field inside the torque converter, the efficiency of squashing design will promote by changing the blade angle in the future.

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