Purpose

This paper aims to study numerically the flow, heat transfer, and entropy generation of aqueous copper oxide-silver hybrid nanofluid over a down-pointing rotating vertical cone, with linear surface temperature (LST) and linear surface heat flux (LSHF), in the presence of a cross-magnetic field. In industrial applications, such as oil and gas plants, food industries, steel factories and nuclear packages, the real bodies may contain nonorthogonal walls and variable cross-section three-dimensional forms which this issue can clarify the importance of selective geometry in the present research.

Design/methodology/approach

The mass-based scheme is accomplished for the simulation, and the entropy generation and Bejan number will be analyzed in conjunction with the aforementioned model. It has been hypothesized that two types of boundary conditions (LST and LSHF) as well as five nanoparticle shapes (sphere, brick, cylinder, platelet and disk) present a collection of crucial results. The overseeing PDEs are changed over completely to the dimensionless ODEs, and these are solved by Runge–Kutta–Fehlberg approach combined with a shooting methodology for certain values of physical parameters.

Findings

Subsequent to the fantastic compromise of the computational outcomes with past reports, the outcomes are introduced to conduct the investigation of the hydrodynamics/thermal boundary layers, the skin friction and the Nusselt number, as well as entropy generation and Bejan number. A state of hybrid nanofluid, which exhibits a remarkable increase in heat transfer in comparison to the states of mono-nanofluid and regular fluid, has been found to have the highest Nusselt number; however, the skin friction values should always be taken into account and managed. The entropy generation improves with the mass of the second nanoparticle (silver), while the opposite pattern is exhibited for the Bejan number. Furthermore, the lowest value of entropy generation number belongs to the cylindrical shape of nanoparticles in the LST case. In final, a significant accomplishment of the current study is the accurate output of the mass-based scheme for an entropy analysis problem.

Originality/value

To the best of the authors’ knowledge, for the first time, in this study, a new development of natural convective flow of a hybrid nanofluid about the warmed (LST and LSHF) and down-pointing rotating vertical cone by the mass-based algorithm has been presented. The applied methodology considers the masses of base fluid (water) and nanoparticles (Ag and CuO) as an alternative to the first and second nanoparticles volume fraction. Indeed, the combination use of the Tiwari–Das nanofluid model and the mass-based hybridity algorithm for the entropy generation analysis can be the main novelty of this work.

中文翻译：

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靠近加热的向下旋转垂直锥体的水银-氧化铜混合纳米流体对流的熵产生分析

目的

本文旨在数值研究氧化铜-银混合纳米流体在具有线性表面温度（LST）和线性表面热通量（LSHF）的下指向旋转垂直锥体上的流动、传热和熵产生。存在交叉磁场。在工业应用中，例如石油和天然气工厂、食品工业、钢铁工厂和核设施，实体可能包含非正交壁和可变横截面三维形式，这个问题可以阐明选择性几何在当前研究中的重要性。

设计/方法论/途径

完成基于质量的方案进行仿真，并结合上述模型对熵产生和Bejan数进行分析。假设两种类型的边界条件（LST 和 LSHF）以及五种纳米颗粒形状（球形、砖形、圆柱形、片状和圆盘）呈现出一系列关键结果。监督偏微分方程完全转变为无量纲常微分方程，并通过龙格-库塔-菲尔伯格方法结合针对某些物理参数值的射击方法来求解。

发现

在将计算结果与过去的报告进行了完美的折衷之后，将结果引入到流体动力学/热边界层、表面摩擦和努塞尔数以及熵产生和贝扬数的研究中。与单一纳米流体和常规流体的状态相比，混合纳米流体的状态表现出传热显着增加，已被发现具有最高的努塞尔数；然而，应始终考虑和管理表面摩擦值。熵的产生随着第二纳米颗粒（银）的质量而提高，而贝让数则表现出相反的模式。此外，在LST情况下，熵产生数的最低值属于圆柱形纳米颗粒。最后，当前研究的一个重大成就是针对熵分析问题的基于质量的方案的准确输出。

原创性/价值

据作者所知，在这项研究中，首次通过基于质量的算法，对加热（LST 和 LSHF）和向下旋转垂直锥体的混合纳米流体的自然对流进行了新的发展已被提出。所应用的方法考虑基础流体（水）和纳米颗粒（Ag和CuO）的质量作为第一和第二纳米颗粒体积分数的替代。事实上，结合使用 Tiwari-Das 纳米流体模型和基于质量的杂化算法进行熵生成分析可能是这项工作的主要新颖之处。