轎車發(fā)動機缸內(nèi)流動的三維瞬態(tài)數(shù)值研究.pdf

1、重慶大學碩士學位論文轎車發(fā)動機缸內(nèi)流動的三維瞬態(tài)數(shù)值研究姓名：張志榮申請學位級別：碩士專業(yè)：熱能工程指導教師：冉景煜20051101重慶大學碩士學位論文 英文摘要IIABSTRACTAt present, the engine with higher efficiency and lower pollution is regarded as oneof the major developing projects in many coun

2、tries. The intake process is the key part tothe working circle of the engine. The flow character in the intake process would affectthe spreading velocity of the flame, the stability of the combustion and its combustionef

3、ficiency. In recent years, the topic has been extensively explored nationally andinternationally. How to implement the three- dimensional transient numerical study onthe flow character in cylinder of engine is the hot to

4、pic to all of researches. Thetransient numerical simulation method approaches the real process and the messages ofthe flow fields of the cylinder in the process of the engine can be obtained directly,checking the design

5、of the intake system is fitful or not, and the structure of the intakesystem can be changed on accounts of the need of the engine in order to obtainreasonable the flow fields.Dynamic mesh technique is the key of the tran

6、sient numerical simulation to theintake process of the engine, and the Combined Dynamic Mesh Technique (CDMT) ispresented based on Finite Volume Method (FVM) in this paper. Based on CDMT, theproblem that involves many sl

7、iding sides about the study object is solved. The intakeprocess of 1.9TDI engine produced by DaZhongBaoLai Company is studied withThree- dimensional transient numerical method in this paper. The intake processtransient c

8、haracter of the engine is simulated with different shape intake, different rotatespeed and different compressing ratio, and the same time, the intake process transientcharacter is also investigated with single intake and

9、 two intakes. In the end, the massflow coefficient and volumetric efficiency are analyzed, and turbulent intensity,pressure and velocity fields of engine in the intake process are also discussed in thispaper.The investig

10、ated results show that the shape and the position of intake port have aninsignificant influence on flow field such as velocity distribution, pressure and turbulentintensity in engine at the initial stage. The flow field

11、changes with moving piston duringthe intake process, thus it makes the flow be changed quite complicated, as a result, theflow in the engine is not swirl or tumble flow, and it is the combination of these twoduring the i