Influence of the switch-over period of an alternately active bi-heater on heat transfer enhancement inside a cavity

TL;DR

This study explores how the switching period of an alternately active bi-heater affects heat transfer in a cavity, revealing optimal periods for enhanced thermal performance relevant to processor cooling.

Contribution

It introduces a scale analysis to determine the threshold switchover period for heat transfer enhancement in an alternately active bi-heater system, validated by numerical simulations.

Findings

Alternately active heaters outperform steady single heaters across all switchover periods.

For low switchover periods, alternately active heaters outperform double-symmetric heaters.

Maximum temperature approaches that of a steady single heater at high switchover periods.

Abstract

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 =0.71 and Rayleigh number in the range of 10^3 - 10^6 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 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.