A two-dimensional numerical simulation is carried with the aim to investigate the combined effects of roughness and wall suction on heat transfer performance of a steady-state laminar channel flow. The roughness considered as a square element mounted on the bottom wall of the channel and suction is applied on its walls. Different Reynolds numbers, different suction rates, and various locations of the suction area on the roughness elements are considered. The governing Navier-Stokes equations are solved using open source OpenFOAM software. The results are tested against theoretical results.

It is shown that the simple addition of roughness element increases the local Nusselt number in comparison to that without roughness. That increase is further enhanced when localised suction is applied. In addition, it is observed that by applying suction strategically on the roughness, one can reduce the thickness of thermal boundary layer, and remove or at least weaken the vortical motion behind the back-face of element, which in turn leads to an increase in local Nusselt number, demonstrating that suction is an effective means for improving the heat transfer rate in a laminar channel flow. As continuation of study, the effect of space between two elements was investigated and the best space was obtained. It is found that this method is useful to enhance heat transfer performance, especially at high Reynolds numbers.

进行二维数值模拟，目的是研究粗糙度和壁吸力对稳态层流通道传热性能的综合影响。粗糙度被视为安装在通道底壁上的方形元件，并在其壁上施加吸力。考虑了不同的雷诺数、不同的吸入率以及粗糙元件上吸入区域的不同位置。使用开源 OpenFOAM 软件求解控制 Navier-Stokes 方程。将结果与理论结果进行比较。

结果表明，与没有粗糙度的情况相比，简单地添加粗糙度元素会增加局部努塞尔数。当应用局部抽吸时，这种增加会进一步增强。此外，观察到通过对粗糙度有策略地施加吸力，可以减少热边界层的厚度，并消除或至少削弱元件背面后面的涡旋运动，这反过来又会导致热边界层的增加局部努塞尔数，表明吸力是提高层流通道传热率的有效手段。作为研究的继续，研究了两个元素之间空间的影响，并获得了最佳空间。发现该方法可用于提高传热性能，尤其是在高雷诺数下。