Experimental vibration analysis and baseline signature establishment for a high-speed vapour blower gearbox assembly

Abstract

Vibration analysis plays a crucial role in ensuring the reliability, safety and efficient operation of rotating machinery by enabling early fault detection and condition monitoring. In the present study, vibration characteristics of a high-speed vapor blower-gearbox assembly operating at speed from 1,000 to 16,000 rpm were investigated. Frequency-domain analysis and impact testing were performed using multi-axial acceleration data collected from key bearing locations at both the drive-end and non-drive-end to identify the primary excitation mechanisms. Experimental data reveal that structural resonance, rather than rotational imbalance, predominantly influences the peak vibration amplitudes. The critical natural frequencies, which are linked to the casing support, low-speed shaft coupling and base structure, have been identified in the range of 12,000 to 15,000 rpm. To address the issue of resonance amplification, ribs were strategically integrated into the structure, resulting in an additional mass of 2.5-3.0 kg to enhance stiffness. This modification effectively shifted the natural frequencies of the system away from the operational velocity range, yielding a 30–40% reduction in vibration levels. These findings demonstrate that stiffness optimization enhances dynamic stability, providing a robust foundation for condition monitoring and prognostics of high-speed turbo machinery.