Blade synchronous vibration measurements of a new upgraded heavy duty gas turbine MGT-70(3) by using tip-timing method

Abstract

The work described in this paper is part of a comprehensive prototype test conducted on a heavy duty power generation gas turbine recently upgraded by MAPNA Turbine Engineering and Manufacturing Company (TUGA). A Blade tip-Timing system is proposed to determine the synchronous vibration characteristics of the rotor blades and to validate the design calculations. The last three stages of turbine section are equipped with tip-timing sensors. Six probes are positioned along the circumferential direction for each stage. The locations of sensors are accurately chosen based on the values of the natural frequencies and the number of necessary modes needed to be captured. The vibration parameters of the blades are obtained by post-processing and analyzing of the acquired data. The resonance frequencies are plotted against rotating speed during transient acceleration of the machine and the damping and amplitude of vibration in resonance condition are also determined. The obtained results meet the designer expectations and confirm a safe operation from vibrational point of view.