Abstract:
In the present work, a parametric numerical study is performed for a converging-diverging channel under pulsatile flow conditions. The sinusoidal velocity at the channel entrance provides the pulsatile flow condition. Simulations are performed for transient flow in the range of 0.001 - 0.5 for the Strouhal numbers, 3400 - 6500 for the Reynolds numbers, and 0.025 - 0.5 for the nondimensionalized amplitude values. The thermal-hydraulic performance is reported to compare pulsatile flow conditions with non-pulsatile conditions. The numerical results showed that the Nusselt number decreased as the Strouhal number and nondimensionalized amplitude values increased. In addition, an improvement in heat transfer is observed in pulsatile conditions for the Reynolds number range 3400-5200. It is understood that turbulent pulsatile airflow in a converging-diverging duct has a limited potential for heat transfer improvement in a specific range. The maximum thermal-hydraulic performance coefficient is found to be 1.17 for the Reynolds number of 3412 and for the Strouhal number of 0.001. It is concluded that pulsatile flow provides satisfactory improvement at lower Reynolds numbers than non-pulsatile flow. Moreover, pulsatile airflow in a converging-diverging duct has a limited potential for the heat transfer improvement in a specific range.
