Enhanced heat-source cooling by flow pulsation and porous block

A numerical study has been carried out for forced pulsating flow in a parallel-plate channel with a porous-block-attached strip heat source at the bottom wall. Both the transient non-Darcy flow model taking the effects of the impermeable boundary, inertia, as well as variable porosity into consideration for the momentum equation and local thermal equilibrium model with thermal dispersion for energy transport were employed inside the porous region. Through the use of a stream function-vorticity transformation, the solution of the coupled governing equations for the porous/fluid composite system is obtained using the control-volume method. Comprehensive time-dependent flow and temperature data are calculated and averaged over a pulsation cycle in a periodic steady state. The effects of the important governing parameters, such as the particle diameter, the blockage ratio, pulsation frequency, and pulsation amplitude on the flow behavior in the vicinity of the porous block and the heat transfer rate from the heater are documented in detail. The results show that the cycle-space averaged Nusselt number for pulsating flow is higher than that for steady flow. The heat transfer enhancement factor increases with the increase of particle diameter, pulsation frequent, and blockage ratio, but decreases with the increase of pulsation amplitude. The method combining flow pulsation with a particle-porous heat sink can be considered as an augment heat transfer tool for cooling high-speed electronic devices.