RESEARCH ON BALANCING ROTORS OF DIESEL ENGINE TURBO COMPRESSORS

Abstract

The accuracy of balancing turbocharger rotors is one of the key factors determining the reliability, vibration indicators and service life of the unit. In practice, it is observed that even individual parts balanced by the manufacturer during final assembly can form additional imbalance due to the misalignment of the shaft and compressor impeller axes, which is caused by the joint gap. The article presents the results of experimental studies describing the influence of engine oil on the centering of the shaft and compressor impeller relative to each other and on the reduction of residual imbalance in the high-speed range. The results of the study showed that the imbalance of the turbocharger rotor is closely related to the size of the gap between the shaft and the compressor impeller and the assembly technology. Connections with a larger gap determine larger rotor imbalance values in the entirely studied speed range. The study found that the oil film in the joint gap can act as a hydrodynamic centering medium, reducing the formation of imbalance. The oil acts as a mounting medium during assembly, which reduces the likelihood of micro-scratches and binding on surfaces, allowing for a more even alignment of the shaft and compressor impeller axes during final tightening. The results of the studies have shown that the vibration and dynamic stability of the turbocharger rotor are mainly determined by the size of the gap between the shaft and the compressor impeller and the assembly conditions. A smaller gap and assembly using engine oil allow for a reduction in the eccentricity of the rotor, which reduces the vibration amplitude at high speeds. Vibration studies of the GT15 turbocharger rotor have shown that the rotor vibration amplitude increases with increasing rotation speed, and the first vibration peak is observed at approximately 50-60 thousand rpm. in the rotation speed range.