Thermal modelling of various thermal barrier coatings in a high heat flux rocket engine

Technical Report · Fri Dec 01 04:00:00 EST 1989

OSTI ID:6866094

Nesbitt, J A

Traditional Air Plasma Sprayed (APS) ZrO2-Y2O3 Thermal Barrier Coatings (TBC's) and Low Pressure Plasma Sprayed (LPPS) ZrO2-Y2O3/Ni-Cr-Al-Y cermet coatings were tested in a H2/O2 rocked engine. The traditional ZrO2-Y2O3 (TBC's) showed considerable metal temperature reductions during testing in the hydrogen-rich environment. A thermal model was developed to predict the thermal response of the tubes with the various coatings. Good agreement was observed between predicted temperatures and measured temperatures at the inner wall of the tube and in the metal near the coating/metal interface. The thermal model was also used to examine the effect of the differences in the reported values of the thermal conductivity of plasma sprayed ZrO2-Y2O3 ceramic coatings, the effect of 100 micron (0.004 in.) thick metallic bond coat, the effect of tangential heat transfer around the tube, and the effect or radiation from the surface of the ceramic coating. It was shown that for the short duration testing in the rocket engine, the most important of these considerations was the effect of the uncertainty in the thermal conductivity of temperatures (greater than 100 C) predicted in the tube. The thermal model was also used to predict the thermal response of the coated rod in order to quantify the difference in the metal temperatures between the two substrate geometries and to explain the previously-observed increased life of coatings on rods over that on tubes. A thermal model was also developed to predict heat transfer to the leading edge of High Pressure Fuel Turbopump (HPFTP) blades during start-up of the space shuttle main engines. The ability of various TBC's to reduce metal temperatures during the two thermal excursions occurring on start-up was predicted. Temperature reductions of 150 to 470 C were predicted for 165 micron (0.0065 in.) coatings for the greater of the two thermal excursions.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
• OSTI ID: 6866094
• Report Number(s): N-90-16911; NASA-TM--102418; E--5184; NAS--1.15:102418
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
360203 -- Ceramics
Cermets
& Refractories-- Mechanical Properties
CERMETS
CHALCOGENIDES
COATINGS
COMPOSITE MATERIALS
ENERGY TRANSFER
ENGINES
HEAT FLUX
HEAT TRANSFER
HIGH PRESSURE
JOINTS
LOW PRESSURE
MATERIALS
MATHEMATICAL MODELS
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE TESTING
PHYSICAL PROPERTIES
PROTECTIVE COATINGS
ROCKET ENGINES
SPRAYED COATINGS
TEMPERATURE EFFECTS
TESTING
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES