Thermal shock of alumina by compressed air cooling

Alumina samples has been submitted to mild thermal shocks by quenching in a compressed air flow and the critical temperature difference has been determined for increasing thermal shock severities. Then these critical shocks have been numerically simulated by varying the superficial heat exchange coefficient value until the maximal tensile stress reaches the material strength. The combination of experimental and numerical approaches leads to indirect estimate of the heat exchange coefficient values during the tests.