Finite element method-based three-dimensional frictional contact analysis of turbocharger compressor

Abstract

In the long-distance transport of material, turbocharger compressors are playing an important role. The impeller mounted onto the compressor shaft assembly via interference fit is one of the key components of a centrifugal compressor stage. The assembly creates a complicated frictional contact problem on the interface of the contacting parts when the rotating speed is high. A locomotive-type turbocharger compressor with 24 blades under combined centrifugal and interference-fit loading is used for the analysis. The finite element parametric quadratic programming method that was developed based on the parametric variational principle is used for the analysis of the stress distribution of three-dimensional frictional contact problem between the impeller and the shaft assembly. The advantages of the parametric programming method when compared with the conventional ones are that the penalty factors can be cancelled and the solutions can be obtained directly without tedious iterative procedures such as general incremental iterative method. The effects of fit tolerance, coefficient of friction, the wall thickness of the shaft sleeve, rotational speed, and the contact stress distribution on the contacting surfaces are discussed in section 2. It is found that non-uniform initial amount of interference in the structural design would avoid relative displacement generated and ensure uniformity of the contact stress. To assure the quality of press-fitting, the amount of interference between the shaft sleeve and the shaft should be controlled strictly to avoid the rapid increase of the contact stress. The results obtained play a key role in deciding the proper fit tolerance and improving design and manufacturing technology of the compressor impellers. The current study also provides an effective approach which achieves more reliable interference-fitted connections and more precise assembly accuracy with lower manufacturing cost in the structural design.