Abstract In this study, annular microchannels with a microscale gap of 300 μm were implemented through the concentric superposition of two macro-sized cylinders. Flow area variations along the streamwise direction were created by introducing sinusoidal wave profiles on either the inner or outer wall of the annular gap while keeping the other wall flat. These variations introduced re-entrant effects along the flow direction. Numerical studies using the finite volume method were performed to elucidate the single-phase, steady-state thermal and hydrodynamic performances of the wavy channels, using water as the fluid medium, with an operating Reynolds number range of 800–2200. The predicted results were validated using the available measured data and classical correlations. This study demonstrated the viability of attaining enhanced heat transfer rates of up to 360% of the original straight channel through the inducement of flow area variations with single wavy-walled channels. Despite magnifications of the friction factors, the single wavy-walled channels attained a 120% increment in heat transfer coefficient when evaluated at the same pumping power. Overall, single-walled wavy passages were deemed suitable for heat exchanger designs demanding very high heat removal rates and efficiencies while the conventional serpentine channels were apt for moderately enhancing heat transfer while requiring low pumping power.

中文翻译：

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通过微通道中周期性流动面积变化增强传热

摘要 在本研究中，通过两个大尺寸圆柱体的同心叠加实现了微尺度间隙为 300 μm 的环形微通道。通过在环形间隙的内壁或外壁上引入正弦波轮廓，同时保持另一壁平坦，从而产生沿流向的流动面积变化。这些变化沿流动方向引入了重入效应。使用有限体积法进行数值研究，以阐明波浪形通道的单相、稳态热和水动力性能，使用水作为流体介质，操作雷诺数范围为 800-2200。使用可用的测量数据和经典相关性验证了预测结果。该研究证明了通过单波壁通道引起流动面积变化，实现高达原始直通道 360% 的增强传热率的可行性。尽管摩擦系数被放大，但在相同的泵送功率下评估时，单波壁通道的传热系数增加了 120%。总体而言，单壁波浪形通道被认为适用于需要非常高的热去除率和效率的换热器设计，而传统的蛇形通道适合适度增强传热，同时需要低泵送功率。在相同的泵送功率下评估时，单波壁通道的传热系数增加了 120%。总体而言，单壁波浪形通道被认为适用于需要非常高的热去除率和效率的换热器设计，而传统的蛇形通道适合适度增强传热，同时需要低泵送功率。在相同的泵送功率下评估时，单波壁通道的传热系数增加了 120%。总体而言，单壁波浪形通道被认为适用于需要非常高的热去除率和效率的换热器设计，而传统的蛇形通道适合适度增强传热，同时需要低泵送功率。