LAUSR

In many high-performance compact air-cooling technologies, it is desirable to adopt materials that provide combined heat dissipation with noise reduction (NR) in the same device. A device that adopts such material is termed here as a “noise-reducing heat sink” (NRHS). NRHS design would involve fundamental thermal-acoustic performance tradeoffs, thus necessitating investigation of their combined thermal-acoustic performance. In this article, the thermal-acoustic performance of NRHS is evaluated by determining their thermal-acoustic index (TAI) as a function of airflow rates (Mach number < 0.1). This index is determined by combining thermal resistance as the basis for thermal performance characterization and NR improvement to characterize the acoustic performance. Conventional parallel-plate heat sinks/slit-based geometries, stochastic metal foams, and a designed periodic foam structure are compared as NRHS candidates. The results show that, for the same material volume fraction, stochastic metal foam heat sinks have better combined thermal-acoustic performance compared with a conventional parallel-plate heat sink. A designed periodic foam NRHS is shown to have significantly improved TAI, thus leading the way for NRHS design in compact cooling technologies. For the best combined thermal and acoustic performance, laminar flow is identified as a suitable operational flow regime.