Study on thermal and flow characteristics and correlations of single-phase laminar wavy microchannels

As the need for cooling electronic components rises, the microchannel has become a popular choice for cooling electronic devices due to its exceptional thermal properties and flexible structures. This paper focuses on the heat transfer process of a type of single-phase sinusoidal wavy microchannel and modified configurations. A 3D typical unit model of simple wavy microchannel is established by COMSOL, and steady-state simulations are conducted for cases with the dimensionless amplitude (α) from 0 to 0.25 and the Reynolds number (Re) from 60 to 1000. Temperature, velocity, and pressure distributions are obtained. Relationships between α, Re and the equivalent thermal resistance (R), Nusselt number (Nu), and friction coefficient (f) are investigated. For α between 0.125 and 0.25, Re between 60 and 1000, and Prandtl number (Pr) within (6 ± 0.8), correlations of Nu and f are obtained through the multi-parameter fitting. Performance evaluation criteria of wavy microchannels (PEC_wavy) are calculated, taking the straight rectangular microchannel (α = 0) as a reference. The case with α = 0.25 and Re = 1000 shows the greatest efficiency for Re between 400 and 1000. A modified gapped configuration is proposed to further enhance the heat dissipation ability of the wavy microchannel. Its typical unit under the case with α = 0.25 is analyzed and compared to that of the simple one. The gapped configuration shows better performance than the original one, particularly at middle Res, and the best PEC_gapped occurs at approximately Re = 300.