Session: 11-45-01: Applications of Computational Heat Transfer

Paper Number: 95864

95864 - Heat Transfer and Flow Characteristic of Sinusoidal Wavy Microchannel Heat Sink With Different Phase Shift 

Electronic components generate a tremendous amount of heat. Thus, microchannel heat sinks are promisingly utilized to remove the massive heat flux. Former researchers have been very interested in microchannel heat sinks because of their capacity to improve heat transfer performance. However, the velocity and thermal boundary layers grow continually in a straight microchannel. As a result, the thermal performance of the microchannel degrades. The thermal performance of a microchannel can be improved by disrupting the growth of the boundary layer. One approach to achieve that goal is to develop a wavy channel rather than a straight microchannel (s-MCHS) which hinders the continual growth of boundary layers due to its waviness. Numerous researches suggest that shorter wavelength and higher wave amplitude in MCHS enhances thermal performance. Shorter wavelength and wave amplitude enhance chaotic advection and better mixing of coolant. Thus, heat transfer enhances in shorter wavelength and higher wave amplitude at the expense of higher pressure drop penalty. Although wavelength and wave amplitude in a wavy MCHS has a significant impact on heat transfer, the phase shift (θp) between two wavy walls in a microchannel also impacts the fluid flow and heat transfer. When the upper and lower walls are in different phases, the cross-sectional area of the microchannel varies. The variation of the cross-sectional flow area creates an adverse pressure gradient in the MCHS. Hence, The phase shift causes more flow reversal and better coolant mixing, which results in enhanced heat transfer performance. The goal of the present study is to understand the flow and heat transfer characteristics in wavy MCHS. Three distinct phase shifts are chosen to investigate the effects of phase shifts. Wavy MCHSs with phase shift, θ_p =90^o, 180^o always shows higher Nusselt number (Nu) at the same Reynolds number (Re) than s-MCHS and wavy MCHS with phase shift, θ_p =0^o. An increase in surface area due to phase shifts, θ_p = 90^o and θ_p =180^o in wavy MCHS, is negligible. So, enhancement in heat transfer of phase-shifted wavy MCHS is caused by interruption, reinitialization, and reattachment of boundary layers. In the current numerical analysis, Nu is found to increase with the phase shift and found 7 times higher than s-MCHS for the lowest wavelength and phase shift, θ_p =180^o. Besides higher heat transfer and better coolant mixing, the phase shift in wavy MCHS causes increased shear stress and pressure drop due to chaotic flow in wavy MCHS.

Presenting Author: Titan Paul University of South Carolina Aiken

Presenting Author Biography: Presenting author is an associate professor of engineering at the University of South Carolina Aiken.

Authors:

Abdul Aziz Shuvo Bangladesh University of Engineering & Technology
Md. Omarsany Bappy Bangladesh University of Engineering & Technology
Amitav Tikadar Georgia Institute of Technology
Titan Paul University of South Carolina Aiken
Akm M. Morshed Bangladesh University of Engineering & Technology