Fig 10 Engine Bsfc Sensitivity To Tbc Thickness

Figure 10 shows the effect of putting a thermal barrier coating onto the described engine components and its effect on the brake specific fuel consumption (BSFC) given in grams per kilowatt hour versus the thickness of the thermal barrier coating. This is an engine rated at 286 kilowatts and 1850 rpm and oil cooled. The graph shows both a turbocharged and a turbocompounded version of the engine. A major fuel consumption savings does take place when the engine is turbocompounded. The turbocompounding has an additional hot turbine which extracts energy from the exhaust and puts power back into the engine. We can see that by putting a ceramic coating on the components we can actually decrease the fuel consumption of the engine in both the turbocharged and turbocompounded versions. It does have a little greater effect on the turbo-compounded engine because the coatings will produce more heat in the exhaust and therefore more energy can be extracted from that additional heat.

Figure 11 gives the actual chemistries of the powders. Both powders are being used with a nickel-chrome-aluminum-ytterium (NiCrAlY) bond coat called AMDRY 961. The Zircoa powder and the Cerac powder are similar, but as I mentioned earlier the zircoa powder has about 8% yttria whereas the Cerac is around 10%. The Zircoa powder, as shown in Figure 12, is a spray dryed and sintered material which has a 67 micron particle size; whereas, the Cerac powder is sintered and crushed with a 30 micron average particle size.

AMDRY 961 - NiCrAlY

0 0

Post a comment