Modal Analysis of a TurboMeca(TM) Turbocharger Diffuser

In this paper, vibration analysis of TurboMeca(TM) urbocharger diffuser is investigated. The diffuser is excited by some sources of vibration such as impeller and engine vibration. Three different features and arrangements for connecting the diffuser to casing are considered. In the first scheme, the connection is performed by three bolts. This feature has vibration problem and leads to initiation of cracks in blades and plate of diffuser. In the second corrective design, six bolts are used such that every two bolts are next to each other (120 degrees). In third step, six bolts are used such that they are located in equally angle sector relative to each other (60 degrees). Modal analysis was performed on these three models to extract natural frequencies and mode shapes using the Finite Element Method (FEM). Analysis of the first design manifests the failure due to the interference of the natural frequency of the structure with the rotational speed of the impeller. Results show that the second feature is not acceptable either. The third design gives the better results because there are enough margins between the natural frequencies and exciting frequencies. With this design feature, diffuser is entered into service and no failure has been reported yet.

Keywords:

Turbomeca , Turbocharger , Diffuser , Modal Analysis , vibration