Journal of Thermophysics and Heat Transfer ( IF 1.1 ) Pub Date : 2021-03-29 , DOI: 10.2514/1.t6126 Swastik Acharya 1 , Sukanta K. Dash 2
In the present work, the analysis of natural convection and entropy generation in a square porous cavity, having either a flat or a wavy vertical wall, filled with a non-Newtonian nanofluid is reported. The effect of Rayleigh number (), non-Newtonian power-law index (0.6–1.4), Darcy number (0.0001–0.01), Hartmann number (0–90), and volume fraction of CuO nanoparticles (0–0.12) on heat transfer characteristics has been thoroughly examined. It is found that the average surface Nusselt number for an undulated wall is less than that of a plane wall. for all the cases increases with and and decreases with . The mixing of the nanoparticles with both Newtonian and non-Newtonian fluids enhances the heat transfer only for of 0.01 and less than 30 for all . When is low at 0.0001, the addition of nanoparticles to a fluid enhances the heat transfer for all the cases except of at less than 1. The entropy generation is significant near the vertical wall because of the higher temperature and velocity gradient. The magnitude of is found to be very less as compared with and . , , and increase with an increase in for all cases; however, for a of 60 or 90, there exists an optimum for for a ranging from 0.0005 to 0.001. Finally, the correlation for the average surface as a function of the pertinent input parameters has been proposed for both Newtonian and non-Newtonian fluids, which can be referred in the academics and the industrial world.
中文翻译:
填充非牛顿纳米流体的多孔罩中的自然对流和熵产生
在目前的工作中,报告了在充满非牛顿纳米流体的具有平坦或波浪形垂直壁的方形多孔腔中自然对流和熵产生的分析。瑞利数的影响(),非牛顿幂律指数(0.6–1.4),达西数(0.0001–0.01),哈特曼数(0–90)和CuO纳米粒子的体积分数(0–0.12)对传热特性进行了彻底检查。发现波状壁的平均表面努塞尔数小于平面壁的平均努塞尔数。 在所有情况下,随着 和 并随着 。纳米粒子与牛顿流体和非牛顿流体的混合仅增强了热传递。 0.01和 全部少于30 。什么时候 低至0.0001,在所有情况下,向流体中添加纳米颗粒都会增强热传递,除了 的 在 小于1。由于较高的温度和速度梯度,在垂直壁附近的熵产生很大。的大小 被发现与 和 。 , , 和 随着增加而增加 对于所有情况;但是,对于 60或90 为一个 从0.0005到0.001。最后,平均表面的相关性 已经针对牛顿流体和非牛顿流体提出了作为相关输入参数的函数的方法,这在学术界和工业界都可以参考。