The advancement of non-Newtonian nanofluid innovation is a crucial area of research for physicists, mathematicians, manufacturers, and materials scientists. In engineering and industries, the fluid velocity caused by rotating device and nanofluid has a lot of applications such as refrigerators, chips, heat ex-changers, hybrid mechanical motors, food development, and so on. Due to the tremendous usage of the non-Newtonian nanofluid, the originality of the current study is to explore the influence of nanoparticle radii and inter-particle spacing effects on the flow characteristics of Casson Methanol-based Aluminium alloy $(AA7072)$ nanofluid through a rotating disc with Joule heating and magnetic dipole. The present problem is modeled in the form of partial differential equations (PDEs), and these PDEs are converted into ordinary differential equations with the help of suitable similarity transformations. The analytical solution to the current modeled problem has been obtained by using the Homotopy Analysis Method(HAM) and numerical solutions are obtained by employing Runge-Kutta-Fehlberg method along with shooting technique. The main purpose of the present research work is to analyze the behavior of the velocity and temperature of the nanofluid for small and large radius of the Aluminium alloy$(AA7072)$ nanoparticles and inter-particle spacing. The radial and tangential velocities are enhanced due to rising Ferro-hydrodynamic interaction parameter and the skin friction force for radial and tangential directions are enhanced $10.51\%$ and $2.16\%$ when $h=0.5$. Also. the heat transfer rate is reduced $18.71\%$ and $16.70\%$ when $h=0.5\%$ and $R_p=1.5$. In fact, the present results are compared with the published results and they met good agreement.