Vibrations of Turbochargers

Introduction

Exhaust gas turbochargers used in the automobiles, such as passenger, on-road vehicles, and off-road engines have some discrepancies to the heavy turbomachines applied to the power plants and chemical industries. The first ones are much smaller and work at high rotor speeds in various operating conditions, such as variable rotor speeds, pressures, temperatures, and as well as mass flow rates. Contrary to the automotive turbochargers, the industrial turbomachines are bigger, heavier and mostly operate at a stationary working condition. Due to their large sizes of compressor and turbine wheels, the turbomachines only operate at low rotor speeds between 3,000 to 20,000 rpm. The maximum circumferential velocities of the turbine and compressor wheels used in the automotive turbochargers are approximately 530 and 560 m/s, respectively. The maximum circumferential velocities of the compressor and turbine wheels are determined by the durability of materials at various driving cycles. Their thermo-mechanical characteristics and lifetime depend on the using material, producing method, and as well as driving cycles.