It is essential to account the variability in thermophysical properties such as thermal conductivity to obtain the characteristics of transport properties in industrial thermal systems more accurately. This phenomenon is especially significant in coating protection for rocket chambers, heat exchangers and power generation, wherein cooling techniques are required for sustaining temperature regulation and structural material integrity. At high operating temperatures, the working fluid and hot walls generally emit appreciable radiation. Mathematical models are therefore required which simultaneously analyse all three modes of heat transfer in addition to viscous flow and a variety of other effects including reactions (corrosion, combustion), mass diffusion and rheological behaviour. The modern thrust in nanoscale materials is a major consideration. Motivated by these applications, in this paper, a theoretical examination is implemented to analyse the impact of thermal conductivity variation and thermal radiation on chemically reacting, free convective Powell-Eyring nanofluid flow over a cylinder. The nanoscale effects are accounted by employing the Buongiorno model. The transformed governing equations are numerically solved by using Keller box method under suitable boundary conditions. The comparison results reveal that the obtained results find an excellent match with the results in the literature. The graphs and tables elucidate the impacts of various pertinent parameters on thermo-solutal transport characteristics. It is to be noted that amplifying thermal conductivity variation rises fluid velocity and temperature. Velocity of the fluid decelerates for elevating Darcy number. Magnifying the radiation corresponds to weak radiative flux and stronger thermal conduction which decrease the heat transfer whereas the mass transfer is increased. Furthermore, nanoparticle concentration decreases with greater first-order chemical reaction and Brownian motion parameter values.

必须考虑到热物理性质（如导热系数）的变化，才能更准确地获得工业热系统中的传输性质的特征。这种现象在火箭室，热交换器和发电的涂层保护中尤为重要，其中需要冷却技术来维持温度调节和结构材料的完整性。在较高的工作温度下，工作流体和热壁通常会发出明显的辐射。因此，需要一个数学模型，该模型同时分析粘滞流动和各种其他影响（包括反应（腐蚀，燃烧），质量扩散和流变行为）的所有三种传热模式。纳米材料的现代发展是主要考虑因素。出于这些应用的动机，本文进行了理论检验，以分析热导率变化和热辐射对在圆筒上进行化学反应的自由对流Powell-Eyring纳米流体的影响。通过采用Buongiorno模型可以解释纳米级效应。在合适的边界条件下，采用凯勒盒法对变换后的控制方程进行数值求解。比较结果表明，所获得的结果与文献中的结果非常匹配。图形和表格阐明了各种相关参数对热溶质传输特性的影响。要注意的是，放大热导率变化会增加流体速度和温度。流体的速度由于达西数的增加而减速。放大辐射对应于较弱的辐射通量和较强的热传导，这会减少传热，而传质会增加。此外，随着一阶化学反应和布朗运动参数值的增加，纳米颗粒的浓度降低。