This paper addresses the unsteady hydrodynamic convective heat and mass transfer of three fluids namely air, water, and electrolyte solution past an impulsively started vertical surface with Newtonian heating in a porous medium under the influences of magnetic field and chemical reaction. Suitable dimensionless parameters are used to transform the flow equations and the approximate analytic method employed to solve the flow problem. The results are illustrated graphically for the velocity, temperature, and concentration profiles. Though, low Prandtl numbers produce high-thermal boundary layer thickness, however, as a novelty, the presence of the magnetic field delayed the convection motion hence, the thermal boundary layer thickness is greater for water with high P_r = 7.0 as compared to air with low P_r = 0.71 and electrolyte solution with low P_r = 1.0. Practically, water with a high-Prandtl number can effectively absorb and release heat. This makes water useful in applications such as geothermal heat pumps and solar thermal collectors, industrial processes such as chemical reactions, distillation, and drying, and in oceanography in predicting the movement and behavior of ocean currents, which in turn can impact weather patterns and climate. Another major observation from the study is that the rate of cooling associated with air, water, or electrolyte impacts differently on the product being cooled.

中文翻译：

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磁场和化学反应对多孔介质中牛顿加热的空气、水和电解质流体非稳态对流传热传质影响的近似解析解

本文研究了在磁场和化学反应的影响下，空气、水和电解质溶液三种流体在多孔介质中牛顿加热的脉冲启动垂直表面上的非稳态流体动力对流热和质量传递。使用合适的无量纲参数来变换流动方程并采用近似解析方法来解决流动问题。结果以图形方式说明了速度、温度和浓度分布。虽然，低普朗特数会产生高热边界层厚度，但是，作为新颖之处，磁场的存在延迟了对流运动，因此，与 空气相比，高P _r = 7.0 的水的热边界层厚度更大低P _r  = 0.71 和低P _r  = 1.0 的电解质溶液。实际上，普朗特数高的水可以有效地吸收和释放热量。这使得水可用于地热热泵和太阳能集热器等应用、化学反应、蒸馏和干燥等工业过程，以及在海洋学中预测洋流的运动和行为，从而影响天气模式和气候。该研究的另一个主要观察结果是，与空气、水或电解质相关的冷却速率对被冷却的产品的影响不同。