Abstract We investigate natural convection driven by a horizontal temperature gradient and a vertical concentration gradient in fluid-filled enclosures with obstructions inside it. Within the domain, nine adiabatic and impermeable cylinders are placed, occupying 30% of the domain volume. The Boussinesq approximation is used to account for density variations within the fluid and the flow is fully resolved. The solutal Rayleigh number has been fixed at R a C = 10 6 and the Prandtl number at P r = 5.4 . The Lewis number has been varied in the range of 1 ≤ Le ≤ 100 and the buoyancy ratio in the range of 0.1 ≤ |N| ≤ 10. The rate of heat and mass transfer are compared to those found in single-scalar natural convection, i.e solely thermal or concentration driven convection. Besides, the obtained heat and mass transfer rate in the cylinder-packed enclosure have been compared to those found in a fluid-only domain. We observe that the addition of a destabilizing concentration gradient to a side-heated enclosure results in heat transfer enhancement, which decreases with Lewis number and thermal Rayleigh number. Similarly, the temperature gradient increases the mass transfer, especially at high Lewis numbers and lower concentration buoyancy force over its thermal counterpart. Although the presence of the cylindrical obstacles reduced the flow velocity, the mass transfer was enhanced at lower buoyancy ratio.

中文翻译：

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具有交叉梯度的双扩散对流对具有绝热圆柱障碍的立方体外壳中传热和传质的影响

摘要 我们研究了由水平温度梯度和垂直浓度梯度在内部有障碍物的充满流体的外壳中驱动的自然对流。在域内，放置了 9 个绝热不透水圆柱体，占据域体积的 30%。Boussinesq 近似用于解释流体内的密度变化，并且完全解析流动。溶素瑞利数已固定为 R a C = 10 6 ，而普朗特数已固定为 P r = 5.4 。路易斯数在 1 ≤ Le ≤ 100 的范围内变化，浮力比在 0.1 ≤ |N| 的范围内变化。≤ 10. 传热和传质的速率与单标量自然对流（即单独的热或浓度驱动的对流）中发现的速率进行比较。除了，已经将圆柱封装外壳中获得的传热和传质速率与仅在流体域中发现的传热速率进行了比较。我们观察到，在侧面加热的外壳中添加不稳定的浓度梯度会导致传热增强，这会随着路易斯数和热瑞利数的增加而降低。类似地，温度梯度增加了传质，特别是在高路易斯数和较低浓度浮力下。尽管圆柱形障碍物的存在降低了流速，但在较低的浮力比下传质得到增强。随路易斯数和热瑞利数而减小。类似地，温度梯度增加了传质，特别是在高路易斯数和低浓度浮力下。尽管圆柱形障碍物的存在降低了流速，但在较低的浮力比下传质得到增强。随路易斯数和热瑞利数而减小。类似地，温度梯度增加了传质，特别是在高路易斯数和较低浓度浮力下。尽管圆柱形障碍物的存在降低了流速，但在较低的浮力比下传质得到增强。