Comparing between 1D & 3D Flow Analysis in the On-Engine Small Turbocharger Experimentally and Numerically

Possibilities and limitations of 1D and 3D flow simulations in the vaneless turbocharger turbine of a 1.7 liter SI engine are presented experimentally and numerically. A test setup of the turbocharged engine on dynamometer is prepared to validate the results of numerical modeling. Various performance parameters are measured at 12 different engine speeds and the results of measurement in 3 different engine speeds are presented in this report. The complete form of the volute and rotor vanes is modeled. An extensive study on the number of meshes has been undertaken to ensure the independency to meshes. The modeling of rotating wheel is considered by Multiple Rotating Frames (MRF) technique. Finally, the variations of turbine performance parameters are studied under different pulse frequencies of the engine. The results show that at high engine speeds a 3D unsteady flow simulation is required to get reasonably accurate results. The results presented in current report will be used in simulating three dimensional steady and unsteady compressible flow within the turbine of the turbocharger.