当前位置: X-MOL 学术Int. J. Numer. Methods Heat Fluid Flow › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Computation of non-similar solution for magnetic pseudoplastic nanofluid flow over a circular cylinder with variable thermophysical properties and radiative flux
International Journal of Numerical Methods for Heat & Fluid Flow ( IF 4.2 ) Pub Date : 2020-12-18 , DOI: 10.1108/hff-04-2020-0236
Thameem Basha Hayath , Sivaraj Ramachandran , Ramachandra Prasad Vallampati , O. Anwar Bég

Purpose

Generally, in computational thermofluid dynamics, the thermophysical properties of fluids (e.g. viscosity and thermal conductivity) are considered as constant. However, in many applications, the variability of these properties plays a significant role in modifying transport characteristics while the temperature difference in the boundary layer is notable. These include drag reduction in heavy oil transport systems, petroleum purification and coating manufacturing. The purpose of this study is to develop, a comprehensive mathematical model, motivated by the last of these applications, to explore the impact of variable viscosity and variable thermal conductivity characteristics in magnetohydrodynamic non-Newtonian nanofluid enrobing boundary layer flow over a horizontal circular cylinder in the presence of cross-diffusion (Soret and Dufour effects) and appreciable thermal radiative heat transfer under a static radial magnetic field.

Design/methodology/approach

The Williamson pseudoplastic model is deployed for rheology of the nanofluid. Buongiorno’s two-component model is used for nanoscale effects. The dimensionless nonlinear partial differential equations have been solved by using an implicit finite difference Keller box scheme. Extensive validation with earlier studies in the absence of nanoscale and variable property effects is included.

Findings

The influence of notable parameters such as Weissenberg number, variable viscosity, variable thermal conductivity, Soret and Dufour numbers on heat, mass and momentum characteristics are scrutinized and visualized via graphs and tables.

Research limitations/implications

Buongiorno (two-phase) nanofluid model is used to express the momentum, energy and concentration equations with the following assumptions. The laminar, steady, incompressible, free convective flow of Williamson nanofluid is considered. The body force is implemented in the momentum equation. The induced magnetic field strength is smaller than the external magnetic field and hence it is neglected. The Soret and Dufour effects are taken into consideration.

Practical implications

The variable viscosity and thermal conductivity are considered to investigate the fluid characteristic of Williamson nanofluid because of viscosity and thermal conductivity have a prime role in many industries such as petroleum refinement, food and beverages, petrochemical, coating manufacturing, power and environment.

Social implications

This fluid model displays exact rheological characteristics of bio-fluids and industrial fluids, for instance, blood, polymer melts/solutions, nail polish, paint, ketchup and whipped cream.

Originality/value

The outcomes disclose that the Williamson nanofluid velocity declines by enhancing the Lorentz hydromagnetic force in the radial direction. Thermal and nanoparticle concentration boundary layer thickness is enhanced with greater streamwise coordinate values. An increase in Dufour number or a decrease in Soret number slightly enhances the nanofluid temperature and thickens the thermal boundary layer. Flow deceleration is induced with greater viscosity parameter. Nanofluid temperature is elevated with greater Weissenberg number and thermophoresis nanoscale parameter.



中文翻译:

具有可变热物理性质和辐射通量的磁假塑性纳米流体在圆柱上流动的非相似解的计算

目的

通常,在计算热流体动力学中,流体的热物理性质(例如粘度和导热率)被认为是恒定的。然而,在许多应用中,这些特性的可变性在改变传输特性方面起着重要作用,而边界层中的温差却很明显。这些措施包括减少重油运输系统的阻力,石油提纯和涂料制造。这项研究的目的是根据这些应用中的最后一个应用,开发一个综合的数学模型,

设计/方法/方法

Williamson假塑性模型用于纳米流体的流变学。Buongiorno的两成分模型用于纳米级效果。无量纲非线性偏微分方程已通过使用隐式有限差分Keller box方案求解。包括在没有纳米级和可变性质影响的情况下进行的早期研究的广泛验证。

发现

通过图形和表格仔细观察并可视化了诸如魏森伯格数,可变粘度,可变热导率,索雷特和杜福尔数等显着参数对热量,质量和动量特性的影响。

研究局限/意义

使用Buongiorno(两相)纳米流体模型来表达动量,能量和浓度方程,并具有以下假设。考虑了Williamson纳米流体的层流,稳定,不可压缩的自由对流。体力在动量方程中实现。感应磁场强度小于外部磁场,因此可以忽略。考虑了Soret和Dufour效应。

实际影响

由于粘度和热导率在许多行业(例如石油精炼,食品和饮料,石油化工,涂料制造,电力和环境)中起着主要作用,因此考虑使用可变的粘度和热导率来研究Williamson纳米流体的流体特性。

社会影响

该流体模型显示了生物流体和工业流体的精确流变特性,例如血液,聚合物熔体/溶液,指甲油,油漆,番茄酱和生奶油。

创意/价值

结果表明,通过增加径向的洛伦兹水电磁力,威廉姆森纳米流体速度下降。热和纳米粒子浓度边界层的厚度随着更大的流向坐标值而增加。Dufour数的增加或Soret数的减少会稍微提高纳米流体的温度,并使热边界层变厚。通过更大的粘度参数引起流动减速。随着更大的魏森伯格数和热泳纳米级参数,纳米流体温度升高。

更新日期:2020-12-18
down
wechat
bug