Purpose

Nanofluid research has piqued the interest of scientists due to its intriguing applications in nanoscience, biomedical and electrical engineering, medication delivery, biotechnology, food processing, chemotherapy and other fields. This paper aims to inspect the behavior of the mixed convection magnetohydrodynamic flow and heat transfer induced by a nonlinear stretching/shrinking sheet in a nanofluid with a convective boundary condition. Tiwari and Das mathematical nanofluid model is incorporated in the analysis.

Design/methodology/approach

The mathematical model is initially transformed to a nondimensional form by using dimensionless variables. Then the nondimensional partial differential equations are further transformed to a set of similarity equations by using the similarity technique. These equations are solved numerically by the bvp4c function in MATLAB software.

Findings

For a certain range of the stretching/shrinking parameter, two solutions are obtained. The friction factor and the heat transfer rate escalate due to suction parameter with adding nanoparticles volume fraction by almost 27.15% and 0.153% for the upper branch solution, while the friction factor declines by almost 30.10% but the heat transfer rate augments by 0.145% for the lower branch solution. Furthermore, the behavior of the nanoparticle volume fractions on the heat transfer rate behaves differently in the presence of the mixed convection effect. The temperature of fluid augments with increasing Biot number for both solutions.

Originality/value

The present work considers the flow and heat transfer induced by a stretching/shrinking sheet in a nanofluid using the Tiwari–Das nanofluid model with a convective boundary condition, where the effect of the buoyancy force is taken into consideration. It is shown that two solutions are found for a certain range of the shrinking strength, while the solution is unique for the stretching case. This study is important for scientists working in the growing field of nanofluids to become familiar with the flow properties and behaviors of such nanofluids.

中文翻译：

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由于具有对流边界条件的非线性拉伸/收缩片材引起的纳米流体的 MHD 流动：Tiwari-Das 纳米流体模型

目的

纳米流体研究因其在纳米科学、生物医学和电气工程、药物输送、生物技术、食品加工、化学疗法和其他领域的有趣应用而引起了科学家们的兴趣。本文旨在研究具有对流边界条件的纳米流体中由非线性拉伸/收缩片材引起的混合对流磁流体动力学流动和传热行为。Tiwari 和 Das 数学纳米流体模型被纳入分析。

设计/方法/方法

数学模型最初通过使用无量纲变量转换为无量纲形式。然后利用相似技术将无量纲偏微分方程进一步转化为一组相似方程。这些方程由 MATLAB 软件中的 bvp4c 函数进行数值求解。

发现

对于一定范围的伸缩参数，得到两种解。摩擦系数和传热率因吸入参数而增加，添加纳米粒子体积分数几乎为 27.15%，上分支溶液增加了 0.153%，而摩擦系数下降了近 30.10%，但传热率增加了 0.145%下支解。此外，在存在混合对流效应的情况下，纳米颗粒体积分数对传热速率的行为也有所不同。两种溶液的流体温度都随着 Biot 数的增加而增加。

原创性/价值

目前的工作使用具有对流边界条件的 Tiwari-Das 纳米流体模型考虑了由纳米流体中的拉伸/收缩片材引起的流动和传热，其中考虑了浮力的影响。结果表明，对于一定范围的收缩强度，找到了两种解决方案，而对于拉伸情况，该解决方案是唯一的。这项研究对于在不断发展的纳米流体领域工作的科学家熟悉这种纳米流体的流动特性和行为非常重要。