Tonal and Broadband Noise-Reducing Heat Sinks Using Long-Neck Helmholtz Resonator Arrays and Corrugated Periodic Cellular Materials

Abstract Fans used in convective cooling applications generate undesirable broadband and tonal noise at the blade pass frequency (BPF) and its harmonics. Using separate noise-reducing devices such as mufflers and acoustic linings often increases the overall size of systems, presenting a challenge in space-constrained systems. A noise-reducing heat sink (NRHS) concept is studied to integrate heat dissipation and noise reduction within the same space to address this. A novel Helmholtz resonator (HR) based heat sink, which targets low-frequency noise reduction and heat dissipation, is demonstrated first. The length of the HR neck is increased to reduce its natural frequency, and this long neck made of copper tube is used as a fin for heat dissipation. A long-neck HR array is experimentally tested for acoustic and thermohydraulic performance. Further, the long-neck HR array is integrated with the corrugated periodic cellular materials (CPCM) heat sink, reducing broadband, tonal noise, and heat dissipation. The experimental results for the combined arrangement show that the proposed arrangement can reduce the low-frequency noise along with the broadband noise and also shows an improvement in the thermal performance compared to only a CPCM heat sink at the cost of a minor increase in the pressure drop.