SwRI Troubleshooting Turbomachinery Operating and Installation Problem: Gas Turbine Technology Center

	Field diagnostic services by SwRI engineers keep gas transmission and power generation turbines running.

Vibration, excessive noise, failures, and other dynamics-related problems that limit or prevent operation are often experienced in gas turbines. Unexpected problems may be experienced shortly after installation, after a major repair, or as a result of premature failure. Engineers at Southwest Research Institute (SwRI) are trained and equipped to respond quickly and comprehensively to unscheduled gas turbine outages or performance limitation problems.

SwRI has developed special capabilities

to solve problems in areas such as:

• Rotor Vibration ? Engineering teams equipped to monitor vibration, detect critical speeds, identify rotor instabilities, and balance rotors. Software and expertise to simulate rotor dynamics problems to provide bearing and shaft design correction guidance.

• Structural Resonance ? Capabilities to conduct vibration surveys and impulse or shaker testing to detect structural resonance or excessive excitation sources.

  FEA expertise to provide design guidance.

  	Structural resonance of gas turbine skids detected by on-site investigation of vibration and by impulse testing.

• Flow-Induced Vibration and Noise ? Measurement techniques to identify flow-induced responses across tube bundles, side cavities, and bluff or tapered bodies in flow streams. SwRI experience includes solving flow-induced vibration and noise problems with safety relief valves, heat exchangers, heat recovery steam generators (HRSGs), and flow splitters.

• Surge/Rotating Stall Detection ? Sensors for detecting recirculating flow trends within centrifugal and axial flow compressors as precursors to surge. Experience in detecting rotating stall using pressure transducers and case-mounted accelerometers.

• Blade Stress Audits ? Quick-response

  techniques for evaluating blade operating

  frequency margins, resonance, and resonant stress levels of turbomachinery blades and impellers.

• Failure Analysis ? Root cause diagnoses based on identifying fracture mode and initiation site by metallurgical examination combined with evaluating excitation levels, environmental  conditions, static and dynamic loading, and operating history.

• Alignment and Casing Distortion ?  Monitoring and assessing rotor casing, foundations, and support movement utilizing lasers, tilt sensors, and displacement transducers. Correlation with
  measured thermal gradients and operating trends.

• Thermal Stress Testing and Analysis ? Temperature and stress measurements, trending and correlation with operating parameters to detect thermalgradients, and effect on gas turbine structural components such as case bowing, ovalization, axial growth, and differential growth between casing and rotor. 

Telemetry system transmits strain signals to identify shaft torque, torsional vibration, and blade vibration problems.		Design modifications of HRSG tubing baffles resolve unexpected flow induced vibration problems of newly installed turbine.		Aeroderivative gas turbines generally have higher efficiencies and greater power to weight ratios but are often more prone to material life, blading failures, and rotor vibration than frame design turbines.

SwRI can offer you a full range of capabilities and experience in gas turbine technology including becoming an extension of your engineering department. For more information about troubleshooting turbomachinery operating and installation capabilities at SwRI or how you can contract with SwRI, please contact Klaus Brun, Ph.D., at kbrun@swri.org or (210) 522-5449.