Numerical and experimental study on heat transfer enhancement in microchannel heat sinks with transverse discontinuities

This study systematically evaluates the thermal enhancement effects induced by transverse discontinuities in rectangular microchannel heat sinks. A microchannel design incorporating uniform discontinuities is proposed to enhance heat transfer efficiency. Numerical simulations and experimental results demonstrate that the introduced discontinuities generate secondary flow vortices, which disrupt and reorganize the boundary layer of the main flow. This phenomenon significantly enhances fluid mixing and local thermal dissipation efficiency, leading to improved heat dissipation and reduced wall temperatures. A dimensionless parameter, the fluid regeneration length-to-discontinuity width ratio (β), is introduced to guide structural optimization. Performance evaluation criteria (PEC) analysis reveals that the optimal configuration occurs with seven discontinuities and β = 7.624, achieving a maximum Nusselt number enhancement of 98.97 %. Compared to conventional continuous microchannels, the proposed design improves overall thermal performance by 54.96 % while effectively balancing heat transfer augmentation and flow resistance penalties.