Afridi Muhammad Idrees, Qasim Muhammad, Wakif Abderrahim, Hussanan Abid
Department of Mathematics, COMSATS University Islamabad (CUI), Park Road, Tarlai Kalan, Islamabad 455000, Pakistan.
Laboratory of Mechanics, Faculty of Sciences Aïn Chock, Hassan II University, B.P. 5366 Mâarif, Casablanca 20000, Morocco.
Nanomaterials (Basel). 2019 Feb 2;9(2):195. doi: 10.3390/nano9020195.
The primary objective of the present work is to study the effects of heat transfer and entropy production in a nanofluid flow over a curved surface. The influences of Lorentz force and magnetic heating caused by the applied uniform magnetic field and energy dissipation by virtue of frictional heating are considered in the problem formulation. The effects of variable thermal conductivity are also encountered in the present model. The dimensional governing equations are reduced to dimensionless form by introducing the similarity transformations. The dimensionless equations are solved numerically by using the Chebyshev⁻Gauss⁻Lobatto spectral method (CGLSM). The rate of increase/increase in the local Nusselt number and skin friction coefficient are estimated by using a linear regression model. The expression for dimensionless entropy production is computed by employing the solutions obtained from dimensionless momentum and energy equations. Various graphs are plotted in order to examine the effects of physical flow parameters on velocity, temperature, and entropy production. The increase in skin friction coefficient with magnetic parameter is high for nanofluid containing copper nanoparticles as compared to silver nanoparticles. The analysis reveals that velocity, temperature, and entropy generation decrease with the rising value of dimensionless radius of curvature. Comparative analysis also reveals that the entropy generation during the flow of nanofluid containing copper nanoparticles is greater than that of containing silver nanoparticles.
本工作的主要目的是研究纳米流体在曲面上流动时的传热和熵产生效应。在问题表述中考虑了外加均匀磁场引起的洛伦兹力和磁热效应以及摩擦热导致的能量耗散。本模型中还考虑了可变热导率的影响。通过引入相似变换将有量纲的控制方程转化为无量纲形式。使用切比雪夫-高斯-洛巴托谱方法(CGLSM)对无量纲方程进行数值求解。通过线性回归模型估计局部努塞尔数和表面摩擦系数的增加率。利用从无量纲动量和能量方程得到的解计算无量纲熵产生的表达式。绘制各种图表以研究物理流动参数对速度、温度和熵产生的影响。与含银纳米颗粒的纳米流体相比,含铜纳米颗粒的纳米流体的表面摩擦系数随磁参数的增加幅度更大。分析表明,速度、温度和熵产生随无量纲曲率半径值的增加而减小。对比分析还表明,含铜纳米颗粒的纳米流体流动过程中的熵产生大于含银纳米颗粒的纳米流体。