- 學位論文
進氣管內控制閥對汽缸流場影響之數值研究
A numerical study of flow field in the cylinder by using control valve in the runner
摘要
中文摘要 隨著現代人對操作性能的要求，及對環境品質的提升，引擎的效能及其污染，已被嚴格的要求。而汽缸內的流場現象直接影響引擎性能及廢氣排放，因此現行的引擎設計皆著重在缸內的熱流現象上，期盼能往低污染高效能的目標邁進。 本文將以計算流體力學(CFD)方法進行研究，採用以有限體積法則為基礎的KIVA-3V程式進行模擬，並研究計畫探討在進氣道內設計一控制閥門(control valve)，藉由閥門的影響及引擎轉速的變化對引擎做研究分析，於獲得分析結果後，在經輸出資料之後處理以探討控制閥對汽缸流場之影響，進而探討於不同引擎轉速下相關引擎性能參數情形。 分析結果顯示在進氣道內設計一控制閥對缸內流場有顯著的影響，且隨著控制閥門遮擋面積的增大，其滾流比及渦旋比等參數強度均變強，當轉速升高時，在動能、紊流動能等方面有較強的表現。
並列摘要
Abstract As a result of the demands for the operational capabilities and for the enhancement of the environmental quality, much improvement on the effectiveness of an engine and its pollution reduction has been requested. Since the behavior of the flow field inside an engine will directly impact its performance and emission of exhaust gases, the design of an engine thus focuses on the study of its thermo-fluidic phenomena, with the goals of low emission of pollutants and high performance for the engine. This study used the methodology on computational fluid dynamics (CFD) – KIVA-3V software package, based on control-volume algorithm – to evaluate the design of a control valve in the intake port of an engine. By analyzing the flow field inside the cylinder of an engine, impacts of the engine rotational speeds and the openings of control valve on the behavior of the thermo-fluidic phenomena can be obtained. The results obtained from this study indicated that having a control valve in the intake port of an engine is highly effective for the in-cylinder flow field. As the blocking area of the control valve is increased, the intensities of the flow parameters, such as the flow swirl and tumble, are enhanced. In addition, as the rotational speed of the engine is increased, the performance of the engine, in terms of its kinetic energy and turbulent kinetic energy, is improved.