Effect Of The PIV Window On The Intake And Compression Airflow Fields In The IC Engine

After one hundreds years of development, the internal combustion engine has been widely used in every walk of life. With the increasing concern about the energy sources and environment issues, many countries put up more and more requirement for the power , the economic and the environmental of the IC engine. The airflow field in cylinder plays a key role to the air-oil mixing quality and the combustion performance. To get a more perfect airflow field, for years, many researchers have been done a great deal of analyses and betterment about the geometry shape, the dimensions and the its locations of the combustion room and intake duct.This paper researches the airflow field from a different point of view. Based the reflection effect theory between the intake air flow and the baffle in the cylinder wall, a concave structure embedded in the cylinder is made with its direction against the intake air flow. Then a simulation of the airflow field in the cylinder is done. At the same time, a PIV test is carried out. At the last, by the contrast and analyses between the results of the simulation and test, the reflection effect of the baffle is investigated. This provides more details to the further research of the micro eddy flow formation. The study will do useful reference to a thorough study of the infections between the configuration parameters and the performance. The main work is as follow:At the first, a digital combination geometry model of the intake duct—cylinder—combustion room is established. Then the soft wares of Pro-surf and Pro-am are used to do some work of repair and mesh generation. At last, the airflow motion and distribution rules are simulated with the Star-CD.As a special structure, it cannot be simulated directly by Star-CD. Though the program rework and the special boundary set, the simulation of the special structure process successfully. The specify velocity fields are gained.A PIV test is carried out on the 2135 diesel, some velocity fields at different crank angles with its transverse section about the TDC are gained.Based on the simulation results, the difference of the corresponding fields between the normal cylinder and the special structure is made. At the same time, the velocity fields of the normal and the special structure at the specified transverse section with the same crank angles are analysed. By the contrasts from the theory and test, the thorough effect of the concave structure which play an important role in the formation of micro eddy flow is investigated.