Numerical Investigation of Thermal and Mass Diffusion Characteristics in Chemically Reactive and Magnetite Cu–Al2O3 Water-Based Hybrid Nanofluid Flow over Riga Plate

The existing work intends to explore the thermal and mass diffusion properties in chemically reactive and magnetite hybrid nanofluids (consisting of $\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3/\mathrm{Cu}$ nanoparticles dispersed in ${\mathrm{H}}_2\mathrm{O}$) flow across a Riga plate, considering influential factors like radiation, exponential heat source, viscous dissipation, magnetic field, and activation energy. The governing equations are modified into ordinary differential equations by employing similarity transformation, The bvp4c solver in MATLAB is used to solve differential equations to obtain the numerical solution. The range of non-dimensional parameters 0.1 < Z < 1, 0 < Kp < 0.5, 1 < R < 5, 0.1 < Ec < 0.4, 0.1 < ${\phi }_1$ < 0.4, 0.1 < ${\phi }_2$ < 0.4, 0.1 < $Q_E$ < 0.4, 0.1 < Bi < 0.4, 1 < $R{e}_x$ < 5, and 0.1 < 𝛾 < 0.7. It is detected that temperature distribution enhances with the rise of Hartmann number and radiation, whereas velocity distribution increases with the rise of modified Hartmann number. As activation energy is raised, the concentration profile is also enhanced. Nusselt number increases with a rise of exponential heat source, for numerical values $Q_{\mathrm{E}}$ = 0.2 and $Q_{\mathrm{E}}$ = 0.3. The corresponding Nusselt numbers are 2.8232 $\times {10}^{-0.7}$ and 5.5421 $\times {10}^{-0.7}$, respectively. The hybrid nanofluid flows over the Riga plate has numerous applications in mechanical engineering, including fuel systems, magnetohydrodynamic (MHD) pumps, energy systems, thermal reactors, etc.