ON THE WAVE THEORY IN HEAT-CONDUCTION

This work contains three major components: a thorough review on the re search emphasizing engineering applications of the thermal wave theory , special features in thermal wave propagation, and the thermal wave m odel in relation to the microscopic two-step model. For the sake of co nvenience, the research works are classified according to their indivi dual emphases. Special features in thermal wave propagation include th e sharp wavefront and rate effects, the thermal shock phenomenon, the thermal resonance phenomenon, and reflections and refractions of therm al waves across a material interface. By employing the dual-phase-lag concept, we show that the energy equation may be reduced to that gover ning the heat transport through the metal lattice in the microscopic t wo-step model. The dual-phase-lag concept can thus capture the microsc opic mechanisms in some limiting cases.