Thermal and stratification impacts on fourth-grade nanofluid flow with Cattaneo–Christov double diffusion

Abstract The study of heat and mass transport in non-Newtonian nanofluids has received a lot of attention due to their excellent thermal characteristics and wide range of industrial applications. Studying the heat and mass transport properties of non-Newtonian fluids is essential because of their complicated rheological behavior in contrast to traditional Newtonian fluids. Energy storage, cooling systems, and biomedical applications are just a few of the practical and manufacturing procedures that benefit from the additional thermal conductivity and heat transfer efficiency provided by nanofluids, which are composed of nanoparticles in a base fluid. This exploration communicates melting heat in mixed convective fourth (4th) grade nanofluid flow through stretchable surface. Thermal and solutal stratification impacts are also considered. Additionally, the heat and mass transportation are precisely introduced in this analysis along with a more exact boundary constraint. Cattaneo–Christov binary diffusion and melting condition are taken for two-dimensional fourth (4th)-grade nanofluid model. The main partial differential equations (PDEs) are converted into ordinary differential system (ODS) after utilizing transformation. The analytical solutions were estimated using the optimal homotopy analysis method (OHAM). Furthermore, the consequences of various parameters on physical quantities are discussed. Velocity profile increases for higher estimation of material variables and reduces for Darcy parameter. Radiation parameters increase heat transfer rates and change fluid flow behavior, with significant effects on temperature distribution. Thermal and solutal stratification shows opposite trend for temperature and concentration that significantly affects temperature and concentration profiles. Entropy enhances radiation parameter. The findings of this research are particularly useful in advanced thermal engineering and material sciences, especially in aerospace cooling systems, microfluidic devices, and nanotechnology applications. They additionally provide important insight into the development of MHD-based control mechanisms for enhancing heat and mass transfer performance in industrial coating, extrusion, and energy storage processes.