Analysis of the Thermal Behavior of a Multilayer Slab With Imperfect Contact Using the Dual-Phase-Lag Heat Conduction Model

The thermal behavior of a multilayered slab in imperfect contact using the dual-phase-lag heat conduction model is numerically analyzed, considering a range of heat flux-phase lag, temperature gradient-phase lag, and thermal contact resistance. Wave reflections from both insulated boundaries and contact surfaces take place when the phase lag of the temperature gradient is less than the phase lag of the heat flux. Due to the wave nature of energy transport in composite slabs having much less temperature gradient-phase lag than heat flux-phase lag and with a low thermal contact resistance, an initially low-temperature layer can attain a higher temperature than that of the initially high-temperature layer. For composite slabs with temperature gradient-phase lag higher than the heat flux-phase lag and due to the absence of the wave nature of energy transport and the enhancement of heat diffusion, a thermal disturbance is more quickly felt in the whole domain when the temperature gradient-phase lag increases, although in terms of the interfacial temperature difference, the contact surface shows lower response with increasing temperature gradient-phase lag during early stages of the transient energy transport.