Beyond the engine: PSM pursues exhaust-case solutions

Many experienced 501F owner/operators have been following the development of PSM’s product line for several years and they knew many of the things Manager of Airfoils Engineering Chris Williams spoke about during his presentation. But most were hearing about the company’s move into exhaust-case solutions for the first time.

Williams began with the company’s compressor solutions, which were divided into the following groups:

  • The S1-3 diaphragms, installed without case modification, are designed to run 96,000 hours without repairs. The first set installed was heavily instrumented and operated without restriction on a standard IGV schedule. The speaker said everything worked as predicted: airfoil strain below design limits, accelerometer response minimal at all IGV settings, and no measureable wear on indicators (buttons). Today, six sets of these diaphragms are in service with nearly 25,000 total accumulated hours of service. The fleet leader is north of 12,000 hours.
  • S4-8 501FD diaphragms also are designed for 96,000 hours without repairs. They will be available for commercial application later this year. Features: forged and machined singlet airfoils and ID/OD rings, 180-deg bolted ID seal box with split-line jumper, no welds or case modifications, ID honeycomb improves performance.
  • S9-16 design improvements include ID honeycomb for better sealing, coated hook contact surfaces, and replacement of the belly band with full-penetration welds. The last is based on the company’s success with 7FA S17/EGV assemblies. These diaphragms also will be available for commercial application later this year.

Combustors. Williams said PSM has studied all of the field issues and is offering a drop-in 501F combustor designed for a 24,000-hr/900-start interval. Operating experience to date extends beyond 14,000 hours/400 starts. A substantial reduction in NOx and lower CO emissions compared to OEM hardware was promised.

R1 turbine blades. Next, the airfoil engineer reviewed the historic fleet issues with R1 turbine blades—such as suction-side platform cracking, trailing-edge root slot cracking, etc—and showed by way of detailed graphics the design enhancements incorporated by PSM to address known field distress. The company has 33 sets of R1 blades in service today; the first began operating in 2008. Duty cycles include base load, peaking, and mixed duty. Several sets have logged more than 15,000 hours/500 starts without pressure-side platform distress and with minimal suction-side distress.

R2 turbine blades have been in service since February 2011; 13 sets are now operational. Prediction is a three-interval lifetime. More details available here.

Exhaust design improvements. Williams said PSM engineers understand the exhaust failure modes that the fleet is experiencing—such as strut over temperature and baffle-plate and teardrop issues. The company’s new R4 blade is said to optimize strut-shield and teardrop gas flow. The introduction of exhaust-end components is planned for the end of 2013.

   For more information, contact Jeff Benoit @


Posted in 501 F&G Users Group |

Leave a Reply

Your email address will not be published.