The laminar 2-D blended convection of the nanofluids at different volume fractions has gained interest in the last decade due to an enormous application in technology. The laminar-flow stream system can be further modified by changing the geometry of the channel, adding an external heating source, and changing the initial conditions at which the stream is being influenced. The investigation of this system includes the variation of the geometrical parameters of the channel, Reynolds number, Nusselt number, and type of the nanoparticles used in preparing the nanofluid with water as the base fluid. These parameters constitute a very successful leading to utilize the numerical solutions by using a finite volume method. Regarding heat flow, one side of the channel was supplied by the heat while the temperature of the other side was kept steadily. The upstream walls of the regressive confronting step were considered as adiabatic surfaces. The nanofluids were made by adding aluminum oxide (Al2O3), copper oxide (CuO), silicon dioxide (SiO2), or zinc oxide (ZnO) nanoparticles to various volume fractions in the scope of 1 to 4% and diverse nanoparticle diameters of 25 to 80 nm. The calculations were performed with heat flux, Reynolds numbers (Re), and step height (S) at a range of 100 <  < 600 W/m2, 100 <  Re  < 500, and 3 ≤ S ≤ 5.8, respectively. The numerical study has shown that the nanofluid with SiO2 has the highest value of the Nusselt number (Nu). The distribution area and the Nu increase as Reynolds number increases and diminish as the volume fraction diminishes with the increase of the nanoparticle diameter. The outcome of this paper has shown that assisting flow has shown superiority over the opposing flow when Nu increases.

中文翻译：

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表征纳米流体和加热对折流垂直通道中流动的影响

在过去的十年中，由于在技术上的巨大应用，纳米流体在不同体积分数下的层流二维混合对流引起了人们的兴趣。可以通过更改通道的几何形状，添加外部加热源以及更改影响流的初始条件来进一步修改层流系统。该系统的研究包括通道的几何参数，雷诺数，努塞尔数以及用于制备以水为基础液的纳米流体的纳米颗粒类型的变化。这些参数非常成功，导致通过使用有限体积方法来利用数值解。关于热流，通道的一侧由热量提供，而另一侧的温度保持稳定。回归对向步骤的上游壁被认为是绝热表面。纳米流体是通过将氧化铝（Al2O3），氧化铜（CuO），二氧化硅（SiO2）或氧化锌（ZnO）纳米颗粒添加到1-4％范围内的各种体积分数和25-150 nm的各种纳米颗粒直径而制成的80纳米 使用热通量，雷诺数（Re）和台阶高度（S）分别在100 <<600 W / m2、100 <Re <500和3≤S≤5.8的范围内进行计算。数值研究表明，含SiO2的纳米流体具有最高的Nusselt值（Nu）。随着雷诺数的增加，分布面积和Nu增大，并且随着纳米粒子直径的增加，体积分数减小，Nu减小。