R0 blades allow fogging, online washing

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At least when PSM makes them.

That was the message VP Business Development Jeff Benoit passed to the editors over lunch in Las Vegas two weeks ago. He said dozens of sets of PSM R0 blades—both flared and unflared designs—are installed at customer sites and many more are on order. The flared R0 fleet leader was at about 15,000 hours, he said, and approaching 300 starts.

Rigorous field validation was said to confirm the ability of these airfoils to operate without restrictions regarding fogging and online water washing. No periodic leading-edge dental molds are required.

Benoit responded with the following bullet points when asked the reasons for PSM’s success with its compressor blade:

* Changed the material to a higher-strength alloy.

* Undercut the attachment to address fretting concerns.

* Modified the airfoil thickness to retune the blade.

* Increased blade frequency above the machine’s operating range thereby reducing its vibratory stress response by more than 50%.

* Did not change in aerodynamic performance.

* Did not adversely impact engine performance.

S0-S4. The conversation drifted to the problematic S0-S4 compressor stators. Benoit said the company now was offering these stator rows for flared 7FA+e machines on commercial terms.

Recall that removal of the OEM’s ring segments can be particularly difficult when the carrier ring corrodes in the engine and locks up in the compressor case. Perhaps more importantly, locked up vane carriers are associated with high-cycle fatigue and the possible liberation of some stator vanes.

Benoit noted that PSM had upgraded the design of the first four stator rows to avoid such problems. Specifically, PSM designers opted for smaller carrier segments, added a groove in the carrier to accommodate tooling that facilitates disassembly, and changed to a higher grade alloy to reduce the potential for corrosion and lockup.

In addition, the S3 vane has been redesigned to eliminate failure by high cycle fatigue. And non-uniform spacing of vanes has been incorporated into the S0 and S1 stator rows to reduce the vibratory response of R0 and R1 rotor blades.

PSM’s S0-S4 stators are fully interchangeable as sets and require no other machine modification.

Repair capabilities. Lunch ended with a quick review of PSM’s expanded repair capabilities in Jupiter, Fla. The tour hosted by PSM for users attending the CTOTF Spring Turbine Forum in mid April got rave reviews by engine owners and operators. 7F users who were not party to that field trip and want to learn more should listen to short video at www.psm.com.

Posted in 7F Users Group |

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