Numerical Simulation On The Leakage Flow Characteristics Of The High-pressure Plunger Pair Clearance

Plunger couple is one of the most sophisticated and the most important parts onthe high-pressure oil pump assembly. When the injection pressure increases, it willbring the problem of the seizure and scuffing of the plunger and the fuel leakagebetween plunger and its barrel, consequently adverse the engine running. The sealingof plunger couplings should be taken into consideration, hence this paper did thefollowing research of the leakage problem on the clearance between plunger and itsbarrel:(1) Introduced the high-pressure pump works briefly and establishing the precisephysical model of the important parts on pump. Apart from that, the theoreticalresearch of chamber pressure establishing process and leakage on the clearance weredeveloped. Eventually, this paper analyzed the working characteristics of the pumpand the key technologies of decreasing the leakage and improving the injectionpressure comprehensively.(2) We applied Fluent to do the numerical simulation on the flow characteristic inthe compression process of the plunger. The simulation was a transient calculationand it take the elastic model and the viscous model of the oil into account, so does themotion of piston and ball valve. we got the changes of the chamber pressure andpump’s outlet mass flux. Then we analyzed the oil film pressure distribution and thechanges of oil velocity on the clearance. On the basis, we explored the heatingmechanism and do the perfect analysis of the clearance leakage. At the same time, thestudy on the law of the fuel properties, the geometric structure and piston velocityinfluence on internal flow characteristic of the oil pump.(3) Aiming at the problem of high pressure deformation of plunger couple, wefound the FSI model on the Ansys Workbench. Then study the coupling structuredeformation and oil film flow characteristic. Based on the FSI, comparative analysis ofthe seven kings of structure improvement methods are done for the leakage. Weconcluded the direction of improvement that the fuel leakage will decrease markedlywhen the structure and dimension of the plunger is refined.