ON NUMERICAL COMPUTATIONS OF THE UNSTEADY FLOW FIELD IN A RADIALTURBINE: ASSESSMENT AND VALIDATION OF DIFFERENT MODELINGSTRATEGIES
(English)Manuscript (preprint) (Other academic)
Today, more advanced turbocharging techniques are used together with downsizing to meet future emission legislations. To be able to keep the development costs on a reasonable level, and to be able to assess complex heat transfer and flow phenomena in the turbocharger, numerical simulations are often used. When using these kinds of tools, it is very important to verify the computed results with measured results. In this study, computed global results are compared with measured data for a radial turbine.The size of the radial turbine is typical for a turbocharger used on a two liter gasoline engine for a passenger car. Different turbulence modeling strategies, the RANS and LES approach, were used. Also, two different modeling approaches for the turbine wheel were used, the sliding mesh technique and the Rotational Reference Frame technique. In order to get the correct inflow conditions to the numerical simulations, PIV measurement of the flow entering the turbine have been performed. The measurements were performed in the new gas-stand at SAAB Automobile, Sweden AB in Trollhttan.The results show that the most advanced technique with sliding mesh and LES gave the best agreement with the measurements.The computed flow field in the turbine is assessed, both with focus on obtaining a deeper knowledge of the transonic flow in the turbine and to assess the differences for the computed flowfield with the different modeling strategies.
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-12740OAI: oai:DiVA.org:kth-12740DiVA: diva2:318480