Coated Turbine Blades Combat Circumferential Wear

New turbocharger option increases blade exchange times on engines burning low grade HFO

Baden, Switzerland, 7th September 2010 – For engines burning lower qualities of heavy fuel oil (HFO) and with especially heavy duty operating profiles, ABB Turbocharging has introduced axial turbine blades having hardfaced tips to counter accelerated circumferential wear.

In such applications turbocharger performance and service costs can suffer due to build-up of hard, abrasive combustion residues on and around the turbine diffuser. Wear due to contact between the deposits and the rotating turbine blades causes a loss in turbine diameter and hence an increase in exhaust gases bypassing the turbine. This both reduces turbocharger and engine efficiency and results in more frequent replacement of complete sets of turbine blades.

Economic solution

Using a special, ABB developed coating process, a hard wear resistant layer is applied to the extremities of removable turbine blades. Nicknamed “dragon’s teeth”, only 6 of the hard tipped blades need to be fitted in pairs at 120 degree intervals around the turbine wheel. At this even spacing they are able to scrape away the hard HFO fouling to clear a path for the standard blades, thus minimizing contact with the abrasive residues. The 120 degree spacing of the coated blades also assists rotor balancing as well as ensuring a well distributed scraping effect.

Reduction in wear

The kit of six turbine blades was fitted to a turbocharger operating on a medium speed generator set as part of a package of measures designed to prolong turbine blade and diffuser lifespan. The measures also included a modified diffuser to minimize distortion during cleaning operations and improvements to the turbine washing nozzles

In this early application the “dragon’s teeth” solution reduced wear on the standard blades to a level where only the hard tipped blades needed to be replaced during scheduled turbocharger overhaul. Diffuser maintenance was likewise considerably reduced.

Original equipment or retrofit

As well as being an option on new turbochargers, the new hard tip solution is also offered as part of ABB’s “Hot Part Package” which also includes modified washing nozzles for ABB Turbocharging’s TPL . . -A and TPL. . -C turbochargers on engines operating on HFO. ?

One Response to “Coated Turbine Blades Combat Circumferential Wear”

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   September 6, 2011 at 9:43 pm

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