Combustion chamber vibration

The efficiency of gas turbines is a primary factor for economic success. Every technological possibility must be exploited. This brings new challenges to the secure operation of gas turbines.

Monitoring is required not only of conventional vibration data from bearings and shafts, but also of dynamic pressure vibrations within combustion chambers. To achieve this, several (usually 2-3) high-temperature-resistant pressure sensors are installed within the combustion chamber. These sensors provide dynamic pressure vibrations that are then recorded by Inobalt Expert Vibro devices.

Pressure vibration data contains information that is relevant to machine security and analysis. The first step in analysing this data is to perform FFT-analysis on the pressure signal. An FFT spectrum enables users to determine and monitor narrow-band characteristic values. Expert Vibro devices immediately calculate the TRMS value for each frequency band. TRMS values undergo monitoring and in the event of an alarm, either messages are sent via PROFIBUS to a main control system, or switching occurs at digital outputs. Characteristic values and FFT spectrums are recorded to the Message device's internal data logger. The ProfiSignal software and Vibro option enable users to portray and evaluate measurement data in FFT or cascade diagrams.

Benefits of Inobalt products

• Compact, inexpensive monitoring systems for combustion chamber vibrations
• Independently operating device with a 16 GB data logger capacity
• Universal inputs suited to pressure sensors
• Computation of pressure and narrow-band characteristic values
• Computation of TRMS characteristic values
• Connectivity to control systems via PROFIBUS-DP or digital outputs