Simulation Optimization Study Of Adjustable Vaned Diffuser

The internal combustion engine as the main source of power has been widely used invarious industrial sectors of society, such as power machinery, generator sets and other.However, due to global energy shortage and the worsening of the natural environment, peopleput forward stricter demand on fuel economy and emission of internal combustion. The use ofturbocharger is one of measures for increasing power, increasing torque, reducing fuelconsumption and reducing emissions.Turbocharger can improve the air density and increase suction air so that combustionbecome more fully. Centrifugal compressor which is a very important part of turbocharger hasbeen widely used with its high efficiency, high compression ration and simple in structure.Diffuser as one part of centrifugal compressor, the good or bad performance of diffuser isdirectly related to the good and bad performance of centrifugal compressor. Two structuralforms of diffuser are vaned diffuser and vaneless diffuser. Vaneless diffuser has been widelyused because of simple structure and a wide flow range；the flow range of vaned diffuser isnarrow and stagger angle is sensitive, but efficiency can be achieved acceptable, so sometimesvaned diffuser has been adopted. In order to obtain efficient compressor and performance ofvariable conditions, the adjustable vaned diffuser is used, although the structure is morecomplex, it is still a way to solve to flow range.Previously, good or bad performance of compressor components is obtained throughexperimental method, but this method spends more money and longer time. After the adventof CFD, CFD simulation has been adopted in compressor research. Adjustable vaned diffuseris a very critical component of the adjustable compressor. Therefore, CFD has been used tosimulate vaned diffuser, and it is very important to assess performance of diffuser andcompressor.In order to obtain efficient turbocharger and meet variable condition, adjustablecompressor which adopted adjustable vaned diffuser has been studied. FLUENT software isused to simulate vaned diffuser, four different blade vaned diffusers are designed. At ratedcondition and small flow rate condition the relationship between blade and performance ofvaned diffuser is studied by numerical simulation; three different stagger angles are given foreach blade. At rated condition and small flow rate condition the relationship between staggerangle and performance of vaned diffuser is studied by numerical simulation.