Simulation Of Improvements To Flow Characteristics In Diesel Intake Port By Incorporating Guide Vanes Into The Intake Manifold

With the development of the economy and the progress of society,the number of automobiles is increasing,and the consumption of petroleum energy and the pollution of the environment by automobiles is becoming more and more serious.How to better improve the energy efficiency of the engine and reduce the exhaust emissions are the problems that researchers need to solve at present.The intake air has an important impact on the performance of the diesel engine,such as power,economy,and emissions.By improving the intake air and improving the flow characteristics of the intake duct,it has a good prospect for solving such problems.Therefore,in this paper,by incorporating guide vanes in the intake manifold of a diesel engine,the intake swirls is increased significantly.the generation and combustion of the mixed gas are improved,and the purpose of energy saving and emission reduction of the engine is finally achieved.This paper first introduces the research status of diesel engine air intake system at home and abroad,and systematically analyzes the technologies and methods to improve the quality of diesel engine intake air,and then determines the main research content and technical route of this paper.Secondly,it analyzes the air movement form and mixture formation mode of the FAW Dachai CA4 DD semi-open combustion chamber diesel engine studied in this paper;referring to the prototype size of the diesel engine,a three-dimensional model of the dual intake port of the diesel engine is established using CATIA software,And imported into the CFD software XFlow based on the meshless and lattice Boltzmann method for the simulation analysis of the intake air flow stability;the simulation calculations obtained the flow coefficient and the swirl ratio of the intake port under the valve lift of 2mm,4mm,6mm,8mm,10 mm,and 12 mm.A 3D printer was used to print the model of the diesel air intake port in its original size,and an intake port test bench was built to conduct the air intake steady flow test.Comparing the simulation and bench test results,the two have good consistency.Then,the installation of guide vanes in the intake port changes the flow field distribution characteristics in the intake process,which in turn affects the intake swirl intensity in the cylinder.In order to analyze the influence of structural parameters such as the length,height and torsion angle of the guide vane on the intake swirls,a uniform design was used as the optimization test method.A combination of nine sets of guide vane structural parameters was designed and simulated.The simulation results showed that: Adding vanes at the front end of the spiral intake port increases the speed of particle movement in the cylinder,which can increase the intake swirls of the diesel engine by a large margin without changing the flow coefficient.Finally,regression analysis is performed on the swirl ratio increase results of multiple guide vane inlet models,and the vane parameters that can better improve the swirl ratio of the inlet are 6.5mm in height,64 mm in length,and 25 ° in twist angle.According to this parameter,the guide vane is processed for bench test,and the simulation and steady flow test results are in good agreement.Compared with no guide vane,the swirl ratio is increased by 47.62%,which has a significant effect on improving the formation of mixed gas in the cylinder.