The shaft power of compressors in industrial-type gas turbines exceeds that which is attained by any other axial compressors. Their operating efficiency and availability are thus of prime importance expecially since gas turbines are being increasingly utilized for medium-range and base-load electric power generation. In addition to good aerodynamic design of the blading, correct dimensioning of the compressor blades to withstand the static and dynamic stresses that occur under various service conditions is a decisively important prerequisite for reliable operating performance. Measurement of the dynamic stresses is important for design verification and reliability confirmation.
Within the period between scheduled maintenance of a Model V 94 gas turbine, approx. 3,000 kg of solid particles flow through the compressor blading if the intake ambient air has a dust content of 0.1 mg/m3. The possible resulting erosion, corrosion and fowling negatively affect the long-term operating performance. The paper describes how these harmful effects can be effectively combatted by intake-air filtering, machine washing and blade coatings. The operating experience based on over one million service hours, of which more than one-third is with protected blades, demonstrates the success of the recommended compressor protection methods in achieving remarkably high operating availability.