Numerical and experimental investigations of a condenser fan add-on device

Vairtex Canada Inc.（渥太华，ON）开发了一种无源设备单元，可以安装在工业风冷冷凝器的风扇上，而工业风冷冷凝器通常安装在杂货店的屋顶上，作为制冷系统的一部分。由于这些机组中常用的轴流风机的设计过于简单，部分来自冷凝器的加热流通过风机将再循环到机组的侧面和下部进口。此外，风扇上方靠近旋转轴的再循环区也会将加热的空气吸引回机组。无源去旋涡装置使气流向上定向，使再循环最小化，从而提高了机组的性能，同时通过减少过热来减少驱动风扇的电动机的维护。Vairtex加拿大公司有兴趣通过应用计算工具和实际尺寸单单元组件的仔细能量平衡实验，部分优化其单元（被动叶片的长度尺寸和角度），以用于特定应用。流体流动和温度测量将使用热线风速仪和热电偶进行，并在风机下游流动的中间平面使用导线系统（带或不带Vairtex装置）。风扇将进行能量平衡。这些数据将用作使用标准CFD（计算流体动力学）技术进行数值模拟的边界条件。

Vairtex Canada Inc. (Ottawa, ON) developed a de-swirling passive device unit to be added on top of the fans of industrial air-cooled condensers, which are normally installed at the rooftop of grocery stores as part of their refrigeration systems. Due to the simplistic design of the commonly used axial fans in these units, part of the heated flow coming from the condenser that passes through the fans will recirculate to the side and lower inlets of the unit. In addition, recirculation zones just above the fan, close to the axis of rotation, will also attract heated air back into the unit. The de-swirling passive device units redirect the flow upwards and minimize recirculation, thus improving the performance of the unit, at the same time reducing maintenance of the electrical motors that drive the fans by reducing overheating. Vairtex Canada Inc. is interested in partially optimizing its units (length size and angle of passive blades) for particular applications by applying computational tools and careful energy balance experiments of an actual size single-unit assembly. Fluid flow and temperature measurements will be performed using hotwire anemometry and thermocouples using a traverse system at the midplane of the flow downstream of the fan (with and without the Vairtex unit). An energy balance of the fan will be performed. This data will be used as boundary conditions for a numerical simulation using standard CFD (Computational Fluid Dynamics) techniques.