急冷媒体による多孔体の熱衝撃時の熱応力 : 熱応力分布に与える浸透の影響

概要

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During thermal shock tests of porous materials by cooling media, the cooling media will infiltrate into the materials. Such as infiltration produces large effects on heat-transfer coefficients on the specimen surface and temperature/stress distributions developed with in the specimen. In this paper, we performed thermal shock tests for porous ceramics using compressed air cooling and water flow cooling to estimate the infiltration effect on temperature/stress distributions. The heat-transfer coefficients were estimated with a thermo-couple implanted in a silver specimen. The temperature distributions in the porous specimens under thermal shock were measured using several thermo-couples implanted in the specimens, and the temperature distributions were simulated using a transient heat-transfer equation, taking into account of the infiltration of the cooling media into the specimen. Thermal stress distributions in the specimens were calculated from the estimated temperature distributions. The results revealed that the temperature distribution in a porous specimen changes drastically compared with a dense specimen, and the maximum thermal stress on the cooled surface of the porous specimen was smaller than that of a dense specimen. These phenomena express the reason why porous materials have high thermal shock resistance despite having small fracture strength.
社団法人日本セラミックス協会の論文
2004-03-01