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Thermomechanical Design Criteria For Ceramic-Coated Surfaces, Robert L. Mullen, J. Padovan, Minel J. Braun, Benjamin T.F. Chung, G. Mcdonals, Robert C. Hendricks
Thermomechanical Design Criteria For Ceramic-Coated Surfaces, Robert L. Mullen, J. Padovan, Minel J. Braun, Benjamin T.F. Chung, G. Mcdonals, Robert C. Hendricks
Dr. Benjamin T.F. Chung
Some early history of ceramic applications is presented. Finite element modeling of components to determine service and fabrication loads found inelastic behavior and residual stresses to be significant to component life. Inelastic behavior mitigates peak strains but enhances residual strains. Results of furnace, Mach 0.3 burner, and engine tests are discussed and categorized into design criteria (loading, geometry, fabrication, materials, analysis, and testing). These design rules and finite element analyses are brought to bear on two test cases: turboshaft engine seals, and rocket thrust chambers.
Thermomechanical Design Criteria For Zr02-Y203 Coated Surfaces, J. Padovan, Benjamin T.F. Chung, Glen E. Mcdonald, Robert C. Hendricks
Thermomechanical Design Criteria For Zr02-Y203 Coated Surfaces, J. Padovan, Benjamin T.F. Chung, Glen E. Mcdonald, Robert C. Hendricks
Dr. Benjamin T.F. Chung
Thermocycling of ceramic-coated turbomachine components produces high thermomechanical stresses that are mitigated by plasticity and creep but aggravated by oxidation, with residual stresses exacerbated by all three. These residual stresses, coupled with the thermocyclic loading, lead to high compressive stresses that cause the coating to spall. In the paper a ceramic-coated gas path seal is modeled with consideration given to creep, plasticity, and oxidation. The resulting stresses and possible failure modes are discussed.
Design Charts For Circular Fins Of Arbitrary Profile Subject To Radiation And Convection With Wall Resistances, G. Zhang, Benjamin T.F. Chung
Design Charts For Circular Fins Of Arbitrary Profile Subject To Radiation And Convection With Wall Resistances, G. Zhang, Benjamin T.F. Chung
Dr. Benjamin T.F. Chung
In this work, the optimization for a radiative-convective annular fin of arbitrary profile with base wall thermal resistances is considered. A fourth order Runge-Kutta method is used to solve the associated non-linear governing equa-tions. Further differentiations yield the optimum heat transfer and the optimum fin dimensions. To facilitate the thermal design, design charts for optimum dimensions are proposed. Furthermore, the fin effectiveness for the optimal annular ra-diative-convective fins is presented to check the practicality of the design. http://dx.doi.org/10.2174/1874396X01206010015
A New Look At Optimum Design For Convecting-Radiating Annular Fins Of Trapezoidal Profile, Benjamin T.F. Chung
A New Look At Optimum Design For Convecting-Radiating Annular Fins Of Trapezoidal Profile, Benjamin T.F. Chung
Dr. Benjamin T.F. Chung
This paper deals with a controversial problem in answering the question “Does the optimum fin design always exist? If not, what are the optimization ranges and limitations?” These authors employ a general example of convecting-radiating trapezoidal annular fin with heat transfer at the tip and wall resistance at the interface. The present results indicate that the answer to the above first question is negative. The ranges of fin optimum design under different thermal and physical conditions are proposed. The effects of Biot number, radiation number, the heat loss at the tip, fin profile and overall wall resistance on fin optimization …