A Study on the Influence of Intake Geometry on the Turbocharger Compressor Performance

Increasing demands on the improvement of the performance of the turbocharged internal combustion engine places in turn higher demands on the efficiency of turbochargers. The aerodynamic performance of the turbocharger compressor is influenced by the uniformity of airflow that the impeller receives. Typically, the compressor performance is measured in a gas stand with straight and conical adaptors. The ducting before the compressor in a vehicle is invariably more complex with additional bends than in the gas stand test setup. This creates differences in performance of engine compared to the performance based on the compressor map obtained from the gas stand. In this study, Computational Fluid Dynamic (CFD) simulations are performed for a compressor with a baseline intake that has a single bend and the results are compared with the test data. Subsequently tests and CFD simulations are performed with ducts having additional bends. The CFD results provide insight into the losses arising in the intake. Additional bends and the nature of bends add to total pressure losses and distorts the flow going into the impeller. The inlet distortion and total pressure losses are quantitatively expressed in terms of a set of parameters in order to facilitate comparison of different designs. The intake geometry is modified to improve the overall compressor efficiency by reducing pressure drop and inlet distortion.