Influence of the Switch-Over Period of an Alternately Active Bi-Heater on Heat Transfer Enhancement Inside a Cavity

Increasing power demands on multicore processors necessitate effective thermal management. The present study investigates natural convection heat transfer inside a square cavity with an alternately active bi-heater that mimics two cores of a dual-core processor. Pulsating heat flux condition is implemented on two discrete heaters with a certain switching frequency. The heat transfer characteristics have been investigated for Prandtl number of 0.71 and Rayleigh number in the range of 103-106 using OpenFOAM. The results obtained for alternative active heaters configuration have been compared with that of the steady single heater and steady double-symmetric heaters subjected to the same heat flux. The alternately active heater configuration showed better heat transfer characteristics than a single steady heater for all switchover periods, and better than a double-symmetric heater for low switchover periods. However, it is found that for higher values of the switchover period, the maximum temperature of alternately active heaters configuration touches the temperature of a steady single heater. This threshold switchover period has been determined using a scale analysis. The threshold switchover periods determined from scale analysis are consistent with the results obtained from numerical simulations for different Rayleigh numbers and heater lengths.