Flow structure is an essential aspect for the intensity of natural convective heat transfer in enclosures. Improvements in the enclosure geometry affecting the flow structure can increase the natural convective heat transfer performance. As the dome shaped walls can change the flow direction in a way to improve the flow circulations and natural convection, the present work numerically investigates laminar flow and natural convective heat transfer of air in dome shaped enclosures with three different dome inclinations. The dome shape can be designed for such enclosures by either filleting the corners of a rectangular cavity or replacing one of the adiabatic walls of a square cavity with a dome shaped wall. Therefore, the impact of dome shape utilization is analyzed from these two perspectives by separately considering the rectangular and square enclosures as reference cases. To broaden the investigation for various circumstances, three different Rayleigh numbers and four different cavity inclination angles are considered. Furthermore, the non-dimensional entropy generation rates are computed for each enclosure to evaluate their performance in terms of second law of thermodynamics. The results show that the dome shape wall significantly changes the flow structure by providing a smoother circulation, which facilitates more intensified convection currents by directing the hot fluid to the colder region of the enclosure, hence, establishing a more effective natural convective heat transfer. The computed results reveal that the mean Nusselt number can be augmented up to 22.5 and 25.0% by the utilization of dome shaped enclosure compared to the equivalent rectangular and square enclosures, respectively. The impact of the dome is dependent on the cavity inclination and generally decreases as Ra increases. Besides, the dome shaped enclosure codified by D45 gives the lowest entropy generation value.

流动结构是机柜中自然对流传热强度的重要方面。改善影响流动结构的外壳几何形状可以提高自然对流换热性能。由于圆顶形的壁可以以改善流动环流和自然对流的方式改变流动方向，因此本工作从数值上研究了具有三种不同圆顶形倾角的圆顶形外壳中空气的层流和自然对流换热。可以通过对矩形腔的角进行圆角化或用圆顶形壁替换方形腔的绝热壁之一来将圆顶形设计用于此类外壳。因此，通过分别考虑矩形和正方形外壳作为参考案例，从这两个角度分析了圆顶形状利用的影响。为了扩大对各种情况的研究，考虑了三个不同的瑞利数和四个不同的腔倾角。此外，针对每个外壳计算无量纲熵产生速率，以根据热力学第二定律评估其性能。结果表明，圆顶形壁通过提供更顺畅的循环显着改变了流动结构，通过将热流体引导到外壳的较冷区域，从而促进了更多的对流，从而建立了更有效的自然对流换热。计算结果表明，与等效的矩形和方形围护相比，通过使用圆顶围护，平均Nusselt数最多可以增加到22.5和25.0％。圆顶的影响取决于腔体的倾斜度，通常随着Ra增加。此外，用D45编码的圆顶形外壳给出的熵生成值最低。