Purpose

The purpose of this paper is to analyse the buoyancy flow, mass and heat transfer in coaxial duct under Soret and Dufour effect. The combined effects of the thermal-diffusion and diffusion-thermo coefficients, as well as the Schmidt number, on natural convection in a heated lower coaxial curve were explored using the proposed physical model. The Dufour and Soret effects are taken into consideration in the energy and concentration equations, respectively.

Design/methodology/approach

The dominating mathematical models are converted into a set of non-linear coupled partial differential equations, which are solved using a numerical approach. The controlling non-linear boundary value problem is numerically solved using the penalty finite element method with Galerkin’s weighted residual scheme over the entire variety of essential parameters.

Findings

It was observed that different parameters were tested such as heat generation or absorption coefficient, buoyancy ratio, Soret coefficient, Dufour coefficient, Lewis number and Rayleigh number. Effect of Rayleigh number, absorption/generation and Dufour coefficient on isotherm are significantly reported. For greater values of Lewis number, maximum mass transfer in duct in the form of molecular particles is produced. Buoyancy ratio parameter decreases the average rate of heat flow and increases its mass transfer.

Originality/value

The main originality of this work is to make an application of Soret and Dufour effects in a coaxial duct in the presence of source sink.

中文翻译：

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自然对流过程在具有 Soret/Dufour 效应的同轴管道中得到认可

目的

本文的目的是分析 Soret 和 Dufour 效应下同轴管道中的浮力流动、质量和热量传递。使用所提出的物理模型探讨了热扩散和扩散热系数以及施密特数对加热的下部同轴曲线中自然对流的综合影响。在能量和浓度方程中分别考虑了 Dufour 和 Soret 效应。

设计/方法/途径

主要的数学模型被转换成一组非线性耦合偏微分方程，使用数值方法求解。控制非线性边值问题是使用惩罚有限元法和伽辽金的加权残差方案对所有基本参数进行数值求解的。

发现

据观察，测试了不同的参数，如发热或吸收系数、浮力比、索雷系数、杜福尔系数、路易斯数和瑞利数。瑞利数、吸收/产生和 Dufour 系数对等温线的影响有显着报道。对于较大的路易斯数值，会产生分子颗粒形式的管道中的最大传质。浮力比参数降低热流的平均速率并增加其传质。

原创性/价值

这项工作的主要创意是在存在源汇的同轴管道中应用 Soret 和 Dufour 效应。