Thermal Stress Analysis of Ceramic Pellets for Catalysis

One of the most critical phenomena that limits the lifetime of ceramic catalysts for H2O2 decomposition is represented by substrate break-up as a consequence of thermal shocking. In a recent experimental campaign conducted by Alta S.p.A., Pisa, Italy, fracture of the ceramic support occurred in a Pt/γ–Al2O3 catalytic bed. Because of the catalyst rupture, the onset of a number of flow instabilities and the marked increase of the pressure drop in the decomposition bed led to a severe decrease of the engine thrust. In order to take proper action for enhancing the thermal shock resistance of the catalyst bed it has been necessary to better understand the dynamics of the heat transfer between the decomposing propellant and the catalyst support. In this work a reduced order model of the thermal transient and the associated thermal stresses in the catalyst pellets is presented. The indications provided by the model have therefore been used for orienting the selection of a su...