Session: 12-13-02: Heat Transfer in Electronic Equipment II

Paper Number: 172790

Numerical Investigation of Thermal Performance of Supercritical Co2 in a Wavy Mini Channel 

The demand for high-performance microprocessors and nanodevices is increasing as electronic components become smaller and more complex. However, effective thermal management is severely hampered by their smaller size and higher thermal loads. Due to the significant heat flux generated by essential components, effective heat dissipation is crucial to ensure the reliability and longevity of these devices. For example, microprocessor sizes have been substantially reduced from 100 μm to 1 μm due to developments in microchip manufacturing, resulting in a significant increase in heat flux generation. Microelectronic performance and dependability depend on maintaining the temperature ranges specified by the manufacturer. For example, desktop processors made by AMD and Intel typically have a maximum temperature range of 45–50°C when not in use and up to 95°C when fully loaded. To maintain temperature homogeneity and prevent hot spots, which can impair performance and reduce the lifespan of these components, effective cooling systems are necessary.

Researchers have explored various methods to enhance heat sink performance. Several methods, including passive, active, and compound approaches, have been proposed and investigated to enhance heat transfer. Among other changes, these techniques include using impinging jets, optimizing header designs, and changing the geometry of flow channels.  High voltages and regulated fluid flow are employed in active techniques, such as electrohydrodynamic (EHD) cooling and jet impingement, to increase the heat transfer coefficient and improve thermal performance. On the other hand, passive methods enhance heat dissipation by modifying fluid properties, altering flow behavior, or modifying surface features without requiring external power. Increasing nucleation sites, altering surface wettability, and disrupting boundary layers are among these strategies. Because the trapped gas inside the pores enhances nucleation and greatly increases heat transfer efficiency, coating surfaces with porous metals has proven to be one of the most successful passive techniques.

Here, a numerical study was conducted to investigate the heat transfer performance of supercritical carbon dioxide (s-CO₂) as a coolant within horizontal micro-wavy channels and also compared to that of water. Furthermore, the influence of channel wavy amplitude and wavelength on heat transfer and pressure drop was examined. The heat transfer performance for the interconnection between the channels was also studied. The simulations considered an inlet mass flux ranging from 127.1 kg·m⁻²·s⁻1 to 400 kg·m⁻²·s⁻¹, an inlet temperature between 305 K and 330  K, and an inlet pressure from 7 MPa to 9 MPa. A uniform cooling heat flux was applied, varying from 9 kW·m⁻² to 40 kW·m⁻².The heat transfer coefficient attained a peak value near the pseudocritical temperature. The heat transfer coefficient of s-CO₂ is higher than H₂O near the pseudocritical temperature. The pressure drop of s-CO₂ is smaller than that of H₂O at all temperatures. Furthermore, the influence of channel wavy amplitude and wavelength on heat transfer and pressure drop was examined. Then the effect of interconnection was also examined. It is found that larger wave amplitudes and smaller wavelengths lead to higher heat transfer coefficients and pressure drops. Interconnection in the wavy channel increases the heat transfer coefficient and pressure drop.

Presenting Author: Titan Paul University of South Carolina Aiken

Presenting Author Biography: The presenting author is an Associate Professor of Mechanical Engineering at the University of South Carolina Aiken.

Authors:

Md. Jafor Ikbal Bangladesh University of Engineering & Technology
Tasnimul Islam Bangladesh University of Engineering & Technology
A. K. M. Monjur Morshed Bangladesh University of Engineering & Technology
Titan Paul University of South Carolina Aiken