Computational Investigation of MHD Radiative Flow of Shape-Dependent A l 2 O 3 $$ A{l}_2{O}_3 $$ and F e 3 O 4 $$ F{e}_3{O}_4 $$ Nanofluids in A Semi-Porous Channel

Abstract

This study investigates unsteady MHD radiative nanofluid flow in a semi-porous channel with expanding and contracting walls, focusing on $A{l}_2{O}_3$-water and $F{e}_3{O}_4$-water nanofluids. Unlike many earlier studies that treat nanoparticle shape only indirectly or assume spherical particles, this work incorporates the shape factor through the Hamilton–Crosser model to capture morphology-dependent thermal transport. The governing equations are transformed into similarity form and solved numerically using the modified operational matrix method. The results show that magnetic effects suppress the flow, that wall motion strongly alters both the velocity and temperature fields, and that particle shape significantly changes the effective thermal conductivity and heat-transfer rate. The study provides a more realistic description of coupled magnetic, radiative, geometric, and shape-dependent transport mechanisms, which is useful for thermal control and porous-channel applications.