Diesel Engines
Gas-Turbine Engines
For the last three decades, thermal barrier coatings have been used in gas turbines and other energy generating components with the following purpose: 1. to increase the operating temperature of the engine and thereby improve the energy efficiency, 2. to reduce the cooling requirements of the metallic components in the hot sections of the engines and 3. to extend component life. Thermal barrier coatings (TBCs) are routinely used on combustors, afterburners, stationary vanes and, in some cases, turbine nozzles and blades in aircraft and power generating gas turbines. More recently, attention has been directed to TBCs in low heat rejection diesel engine components to reduce fuel consumption.
It is now recognized that energy generating gas turbines and diesel engines operate at higher efficiencies at increased temperatures. For example, a 100šC increase in the gas turbine inlet temperature provides an increase in the power output from 8 to 13%, along with a 1 to 4% increase in the single cycle efficiency. Using a figure of $14B as the annual US energy budget for turbine fuels alone, a 1% increase in efficiency leads to $140M per year savings in power generation costs. In the case of diesels, it has been reported that a 1 mm thick coating on the cylinder head and a 2 mm thick coating on the piston caps reduces the heat losses into the water coolant by 9%, while increasing the heat losses into the oil by 3%, for an overall reduction of 6%.(1) The other benefits of an LHR engine include increased power density for greater horsepower from smaller displacement, decreased maintenance costs and increased reliability, associated with the elimination of the water cooling system.(2)
Diesel Engines
Gas-Turbine Engines
(1) I.Kvernes and O.Noerholm, Coatings for Advanced Heat Engines Workshop, DOE, Washington D.C. (1987) pp. II-73.
(2) R.A.Miller, Coatings for Advanced Heat Engines Workshop, DOE, Washington D.C. (1987) pp. II-7.
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last updated 5/20/96 by Dr. T. Jewett