Study On Three-dimensional Numerical Stimulation Of Flow Field And Performance Of Diesel Helical Intake Port

Intake systems,fuel injection system and the structure of combustion chamber are composed of three major components of combustion system during the engine working process.The reasonable match between them is not only helpful in ensuring the quality of combustion of the working substance,but also the engine’s comprehensive performance can be improved.Helical intake port plays an important role in the intake system,and volumetric efficiency,the distribution of velocity and pressure of gas and the formation of swirl are influenced by the structure of helical intake port,and then the dynamic property,the economical efficiency and the environmental-friendliness of the engine can be the remarkably enhanced.Therefore,it is beneficial for engine to get accurate flow coefficient and swirl ratio by studying the performance of helical intake port and designing appropriate parameters of intake port that are of great importance for engine performance optimization.The traditional experience of design and steady flow test rigs usually were used to research new intake port in the past,however they are time-consuming,high-energy and expensive.It can save time by using three-dimensional simulation software to simulate intake port which can easily gain comprehensive evaluation parameters and flow field information of intake port and cylinder.Wei chai 6160 diesel helical intake port is utilized to simulate and analyze during the subject.Firstly,mathematics and theory method must be defined whenever the helical intake port is simulated and three-dimensional turbulent flow of information of intake port is analyzed.Secondly,steady simulation and transient simulation of three-dimensional geometric model of helical intake port can be carried out by AVL-Fire software and CONVERGET?software.Flow coefficient,swirl ratio,field characteristics of nephogram which contains trace chart of gas flow,turbulent kinetic energy diagrams and contour map of the speed under different valve lifts can be obtained through steady state simulation.Swirl ratio and the turbulent kinetic energy can be obtained by transient simulation and then trends of it are analyzed in detail and presentation.Defective structures of helical intake port can be found through analyzing field characteristics of nephogram and optimized by 3D modeling software which includes CATIA and Pro/Engineer and then optimized intake port will be simulated again.As a result,flow coefficient and swirl ratio of optimized helical intake port can be improved 10%-20%and flow field distribution will be improved that can own reference value about enhancing air inflow of engine.