Impacts of double rotating cone system and magnetic field on mixed convection in a 3D U-shaped porous channel are analyzed with finite element method. Impacts of different influencing parameters such as Richardson number (between 0.05 and 50), Hartmann number (between 0 and 100), rotational speed of the cones (between −5000 and 5000), size of the cones (between 0 and 0.075H) and aspect ratio (between 0.4 and 2) on the flow and heat transfer are scrutinized. It was revealed that the average decreases when higher values of Richardson number, magnetic field strength are considered while the impact is reverse for angular speed, size and aspect ratio of the cones. The hot walls of the U-channel contribute to overall heat transfer differently and the variation is significant for different pertinent parameters. The average of hot wall near the exit is reduced by about 20% at the highest Richardson number. The magnetic field reduced the effective convention while significant increment of the average Nusselt number of the bottom wall is observed with higher size and speed of the rotating cones. The size effect is influential in the case of rotation and up to 143% increment in the average is attained for the highest size with highest speed of the cones while this amount is only 9.5% for a stationary cone. Enhancements up to 84% in the average is obtained with rotation of the cones while aspect ratio contributed to only 10% increment. A multi-parametric POD analysis for the evaluation of local and average Nusselt numbers of the hot surfaces of the U-shaped cavity is performed. The number of modes required to represent the data in the parametric space is 20, 20 and 48 for left, right and bottom surfaces.

中文翻译：

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双旋转锥体和磁场对多孔 3D U 形弯管中纳米流体混合对流的联合影响


采用有限元方法分析了双转锥系统和磁场对三维U形多孔通道内混合对流的影响。不同影响参数的影响，例如理查森数（0.05至50之间）、哈特曼数（0至100之间）、锥体旋转速度（-5000至5000之间）、锥体尺寸（0至0.075H之间）和仔细检查纵横比（0.4 至 2 之间）对流动和传热的影响。结果表明，当理查森数、磁场强度的值较高时，平均值会降低，而锥体的角速度、尺寸和纵横比的影响则相反。 U 形通道的热壁对整体传热的贡献不同，并且对于不同的相关参数，变化很大。在理查森数最高时，出口附近的热壁平均减少约20%。磁场降低了有效对流，同时随着旋转锥体的尺寸和速度的增大，观察到底壁的平均努塞尔数显着增加。尺寸效应在旋转的情况下是有影响的，对于最大尺寸和最高速度的锥体，平均增量高达 143%，而对于静止锥体来说，这一增量仅为 9.5%。通过锥体的旋转，平均增强了 84%，而纵横比仅贡献了 10% 的增量。进行了多参数 POD 分析，用于评估 U 形腔热表面的局部和平均努塞尔数。对于左面、右面和底面，表示参数空间中的数据所需的模式数量为 20、20 和 48。