双层矩形扩张微通道换热行为数值模拟研究

Numerical Study on Heat Transfer Behavior of Double-Layer Rectangular Expanding Microchannels

摘要: 针对传统微通道散热器热工水力性能耦合优化的不足，以及变截面结构与双层微通道架构融合研究的匮乏问题，本文提出一种新型双层矩形扩张微通道热沉(DL-MCHS)，并采用数值模拟方法对其换热行为展开系统研究。设计了长宽高为30 mm × 15 mm × 3 mm的热沉物理模型，以水为冷却介质，发热功率100 W的硅芯片为热源，构建三维固–流热交换耦合数学模型，探究了不同体积流量对该热沉传热与流动特性的影响规律。结果表明，当体积流量从2.08 × 10⁻⁶ m³/s提升至6.24 × 10⁻⁶ m³/s时，芯片最高温度由338.53 K降至330.05 K，系统热阻由0.4538 K/W降至0.369 K/W，降幅分别达2.5%和18.7%，但散热强化效应存在边际递减趋势，流量超过5.20 × 10⁻⁶ m³/s后降温效果显著减弱；同时，体积流量提升使流动阻力增大，压降从163.64 Pa增至432.14 Pa，泵送功率从0.68 mW上升至1.80 mW，二者均呈线性特征。本研究揭示了双层矩形扩张微通道热沉的热工水力性能耦合机制，为高热流密度电子器件热管理的微通道结构设计与流量优化提供了理论依据和数据支撑。

Abstract: Aiming at the shortcomings of the coupled thermal-hydraulic optimization of conventional microchannel heat sinks and the lack of research on the integration of variable cross-section structures and double-layer microchannel architectures, a novel Double-Layer rectangular expansion Microchannel Heat Sink (DL-MCHS) is proposed in this paper, and its heat transfer behavior is systematically investigated using numerical simulation. A physical model of the heat sink with dimensions of 30 mm × 15 mm × 3 mm is designed. With water as the cooling medium and a silicon chip with a heating power of 100 W as the heat source, a three-dimensional solid-fluid thermal exchange coupled mathematical model is established to explore the effects of different volume flow rates on the heat transfer and flow characteristics of the heat sink. The results show that as the volume flow rate increases from 2.08 × 10⁻⁶ m³/s to 6.24 × 10⁻⁶ m³/s, the maximum chip temperature decreases from 338.53 K to 330.05 K, and the system thermal resistance decreases from 0.4538 K/W to 0.369 K/W, with reductions of 2.5% and 18.7%, respectively. However, the heat transfer enhancement effect exhibits a marginal diminishing trend, and the temperature reduction is significantly weakened when the flow rate exceeds 5.20 × 10⁻⁶ m³/s. Meanwhile, the increase in volume flow rate leads to higher flow resistance: the pressure drop rises from 163.64 Pa to 432.14 Pa, and the pumping power increases from 0.68 mW to 1.80 mW, both showing linear characteristics. This study reveals the coupled thermal-hydraulic mechanism of the double-layer rectangular expansion microchannel heat sink, providing a theoretical basis and data support for the microchannel structure design and flow rate optimization in thermal management of high-heat-flux electronic devices.