Thermal Cyclic Fatigue of Porous Ceramics for Hot Gas Filters
asushi MATSUSHIMA, Satoshi KITAOKA, Hideo AWAJI, Chun-Hong CHEN, Jianwu CAO, Fusayuki NANJO, Hiroshi MUTO, Shinji IKEDA and Yushuke TADAKUMA
Abstract:A thermal cyclic fatigue testing method is proposed for hot gas tube filters made of SiC porous ceramics. The method simulates reverse pulse cleaning of the outer surfaces of the filters during dust removal. O-ring specimens cut from the ceramics were thermally shocked by cyclically blowing air outward through the specimens exposed to a high temperature flue gas. The inner subsurface layer of the specimens fractured preferentially as a result of the thermal tensile stress produced by the temperature difference between the inner and outer surfaces of the specimen. The thermal cyclic fatigue diagram was shown from the maximum thermal tensile stresses calculated on the basis of non-equilibrium thermal conduction, and the O-ring compression fracture behavior of the specimens after the thermal cyclic fatigue tests. The critical conditions that result in the fatigue fracture are given. Key Words:Thermal cyclic fatigue, Porous ceramics, Hot gas filter, Silicon carbide, O-ring compression test, Strength, Thermal stress