Turbo manufacturer addresses blade wear issues

31 Jul 2010
ABB Turbocharging’s turbine blades with hard wear resistant tips are designed to scrape away hard HFO fouling on turbocharger turbine diffusers to minimise contact of standard blades with the abrasive deposits

ABB Turbocharging’s turbine blades with hard wear resistant tips are designed to scrape away hard HFO fouling on turbocharger turbine diffusers to minimise contact of standard blades with the abrasive deposits

ABB Turbocharging of Switzerland has introduced new turbine blades for engines burning lower qualities of HFO and with especially heavy duty operating profiles. The axial turbine blades feature hard-faced tips to counter accelerated circumferential wear.

When operating at high load with low-grade HFO turbochargers can suffer 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 reduces turbocharger and engine efficiency and results in more frequent replacement of complete sets of turbine blades.

ABB has addressed this problem through the development of a coating process, in which a hard wear resistant layer is applied to the extremities of removable turbine blades. Not all of the blades need to be coated; ABB estimates that six of the hard-tipped blades, known as ‘dragon’s teeth’, fitted in pairs at 120° intervals around the turbine wheel, will be sufficient. At this spacing the blades are able to scrape away the hard HFO fouling to clear a path for the standard blades, thus minimising contact with abrasive residues. The 120° spacing of the coated bladed assists rotor balancing as well as ensuring a well distributed scraping effect.

As well as being an option on new turbochargers, the hard tip solution is offered as part of the ‘hot part package’ which includes modified washing nozzles for ABB Turbocharging’s TPL . . -A and TPL. . -C turbochargers on engines operating on HFO.

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