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Aero and Vibroacoustics of Automotive Turbochargers is a topic involving aspects from the working fields of thermodynamics of turbomachinery, aerodynamics, rotordynamics, and noise propagation computation.
In this broadly interdisciplinary subject, thermodynamics of turbomachinery is used to design the turbocharger and to determine its operating conditions. Aerodynamics is needed to study the compressor flow dynamics and flow instabilities of rotating stall and surge, which can produce growling and whining-type noises. Rotordynamics is necessary to study rotor unbalance and self-excited oil-whirl instabilities, which lead to whistling and constant tone-type noises in rotating floating oil-film type bearings. For the special case of turbochargers using ball bearings, some high-order harmonic and wear noises also manifest in the rotor operating range. Lastly, noise propagation computation, based on Lighthill's analogy,is required to investigate airborne noises produced by turbochargers in passenger vehicles.
The content of this book is intended for advanced undergraduates, graduates in mechanical engineering, research scientists and practicing engineers who want to better understand the interactions between these working fields and the resulting impact on the interesting topic of Aero and Vibroacoustics of Automotive Turbochargers.
List of contents
Introduction to Turbocharging.- Induced Noise Types.- Acoustic Propagation Theory.- Analyzing Root Causes of Noise.- Computational Nonlinear Rotordynamics of Turbochargers.- Subsynchronous Constant Tone.- Eigenfrequency Modifications to Reduce Constant Tone Level.
About the author
Dr. Hung Nguyen-Schaefer is a senior expert in rotor-dynamics and bearing designs of turbochargers at Bosch Mahle Turbo Systems (BMTS) in Germany. He received his B.Sc. and M.Sc. in mechanical engineering with nonlinear vibrations in fluid mechanics from the University of Karlsruhe, Germany in 1985, and his Ph.D. in nonlinear thermo- and fluid dynamics from the same university. In 1988 he joined Bosch company, and worked as technical manager on many development projects of anti-lock braking and traction systems, high-pressure fuel injection systems, combustion engine systems, fluid cavitation, and electric turbochargers for automotive fuel cells (PEMFC). Since 2007 Dr. Nguyen-Schaefer has been in charge of rotordynamics and bearing design of automotive turbochargers at BMTS located in Stuttgart, the joint venture of Bosch and Mahle. He has much experience in the fuel injection systems of gasoline, diesel, compressed natural gas (CNG), automotive turbochargers, rotordynamics, and bearing designs.
Summary
Aero and Vibroacoustics of Automotive Turbochargers is a topic involving aspects from the working fields of thermodynamics of turbomachinery, aerodynamics, rotordynamics, and noise propagation computation.
In this broadly interdisciplinary subject, thermodynamicsof turbomachinery is used to design the turbocharger and to determine its operating conditions. Aerodynamics is needed to study the compressor flow dynamics and flow instabilities of rotating stall and surge, which can produce growling and whining-type noises. Rotordynamics is necessary to study rotor unbalance and self-excited oil-whirl instabilities, which lead to whistling and constant tone-type noises in rotating floating oil-film type bearings. For the special case of turbochargers using ball bearings, some high-order harmonic and wear noises also manifest in the rotor operating range. Lastly, noise propagation computation, based on Lighthill’s analogy,is required to investigate airborne noises produced by turbochargers in passenger vehicles.
The content of this book is intended for advanced undergraduates, graduates in mechanical engineering, research scientists and practicing engineers who want to better understand the interactions between these working fields and the resulting impact on the interesting topic of Aero and Vibroacoustics of Automotive Turbochargers.
