Abstract Three-dimensional study of convection-radiation heat transfer of a discrete heat source (chip) inside an enclosure cooled by rectangular finned heat sink is studied. Conduction heat transfer through the enclosure walls and radiation exchange between these walls are considered. Convection heat transfer on the outer surfaces of the enclosure to the ambient is considered. A complete three-dimensional mathematical model of the physical system is presented and solved numerically by using finite difference method and programmed inside MATLAB software and validated by using an experimental work. Results show good agreement between the numerical and experimental results in case of considering radiation. The impact of the enclosure aspect ratio and chip power on its cooling and heat transfer and fluid flow inside the enclosure is investigated. The results indicate that in an enclosed electronic device, the impact of the radiation is important in the thermal analysis when the natural convection cooling is presented. At chip heat flux of 5 kW/m2, neglecting radiation impact rises chip temperature by about 20%. The minimum chip temperature is obtained at an aspect ratio of 1.25. Increasing the chip heat flux and aspect ratio reduces the airflow eddies inside the enclosure. At chip heat flux of 1.25 and 5 kW/m2, radiation Nusselt number represents about 17.8 and 19.7% of the total Nusselt number, respectively.

中文翻译：

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由散热器冷却的外壳内电子芯片对流-辐射传热的 3D 研究

摘要 研究了由矩形翅片散热器冷却的外壳内离散热源（芯片）对流-辐射传热的三维研究。考虑了通过外壳壁的传导热传递和这些壁之间的辐射交换。考虑了外壳外表面上到环境的对流传热。提出了一个完整的物理系统三维数学模型，并采用有限差分法对其进行了数值求解，并在MATLAB软件中进行了编程，并通过实验工作进行了验证。结果表明，在考虑辐射的情况下，数值和实验结果之间具有良好的一致性。研究了外壳纵横比和芯片功率对其冷却和传热以及外壳内流体流动的影响。结果表明，在封闭的电子设备中，当出现自然对流冷却时，辐射的影响在热分析中很重要。在芯片热通量为 5 kW/m2 时，忽略辐射影响会使芯片温度升高约 20%。在纵横比为 1.25 时获得最低芯片温度。增加芯片热通量和纵横比可减少外壳内的气流涡流。在芯片热通量为 1.25 和 5 kW/m2 时，辐射努塞尔数分别约占总努塞尔数的 17.8% 和 19.7%。在纵横比为 1.25 时获得最低芯片温度。增加芯片热通量和纵横比可减少外壳内的气流涡流。在芯片热通量为 1.25 和 5 kW/m2 时，辐射努塞尔数分别占总努塞尔数的 17.8% 和 19.7%。在纵横比为 1.25 时获得最低芯片温度。增加芯片热通量和纵横比可减少外壳内的气流涡流。在芯片热通量为 1.25 和 5 kW/m2 时，辐射努塞尔数分别约占总努塞尔数的 17.8% 和 19.7%。