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題 名 | 聯結貨櫃車之流場數值研究=Numerical Simulation of the Flow Structure around Connect-truck |
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作 者 | 戴昌賢; 苗志銘; 陳俊中; | 書刊名 | 國立屏東科技大學學報 |
卷 期 | 10:2 2001.06[民90.06] |
頁 次 | 頁119-130 |
分類號 | 557.17 |
關鍵詞 | 氣動力係數; 聯結貨櫃車; 側向風; 整流罩; 計算流體力學; Aerodynamic data; Connect-truck; Crosswind; Deflator; CFD; |
語 文 | 中文(Chinese) |
中文摘要 | 本文主要研究目地是使用計算流體力學之方法,探討大型貨櫃聯結車在具有整流罩及承受不同側向風下,所引發之複雜流場現象並求算出動力係數。車輛整流罩增設是影響氣動阻力係數的重要因素,而如何使車輛達到降低阻力係數剛減少燃油消耗率對於車輛工業之發展有著關鍵性的影響,另一方面,側向風對於高速行駛車輛之安全性也必須詳加考量以訂定適當之限速值。鑑於此流場的現象十分複雜且不易計算,因此本研究開發出一套有效率的數值方法,其主要數值方法為上風通量差分之有限體積法(finite volume method),據以求解流經此類型車輛外形的流場結構與特性。本文主要參數為探討貨櫃車加裝整流罩(deflector)在不同側風狀態下車輛流場各類型氣動力係數的變化情形。本研究結果顯示整流罩之增設對貨櫃車確有降低阻力係數之功效。然而當側向風角度高於15度時,整流罩之裝設反而造成俯仰力矩之增昇,對車輛之安全性有不利之影響。另一方面,本研究也模擬出之貨櫃車在側風(crosswind)狀態下流線分佈情形,協助釐清聯結貨櫃車周圍氣流運動的流動機制。 |
英文摘要 | t the crosswind effect on the aerodynamic behavior of connect-truck with and without deflator is numerically investigated in present study. In the process of vehicle industry development, the connect-truck with deflator is a widely approvable concept. It is believed that the installation of deflator can reduce the aerodynamic drag coefficient, so the fuel consumption can be lower. However, in the Taiwan, at exposed locations such as embankments or high river bridges, wind induced high vehicle accidents are a common occurrence. The existence of deflator results in the increase of leeward side area of vehicle in crosswind, so either the vehicle will be completely blown over or deviated significantly from its original path. From the view of vehicle safety, the effect of crosswind should be seriously considered. Present study proposes an effective numerical model that is based on the Computational Fluid Dynamics (CFD) theory. The topology of test vehicle and the grid system is constructed by the commercial package, namely ICEM/CFD. The solver is HASP (High performance Aerodynamic Simulation Package), which is developed by the authors based on the Roe's upwind flux differencing scheme of control volume method. After the numerical iterations are finished, the aerodynamic data and detailed complicated flow structure are visualized by commercial packages of Field View and Tecplot. Results show that the deflator reduces the drag force coefficient when the yaw angle, the angle between the wind vector and the vehicle direction of travel, below fifteen degree. Meanwhile, for the connect-truck with deflator, the obviously increasing of pitch moment with yaw angle indicated the crosswind resulting in seriously problems in the view of driving safety. Detailed flow patterns (streamlines and pressure contours) can help the vehicle designer to improve the performance of deflator. In addition, the aerodynamic data can support the government officers in regulating the limit speed in different locations for avoiding accident, which is suited for Taiwan. |
本系統中英文摘要資訊取自各篇刊載內容。