Comprehending the behaviour of ternary hybrid nanofluids with the influence of couple stress effects on a flat plate will provide vital insights for the development of more effective heat exchangers and cooling systems. In this investigation, we analyzed the impact of various factors, including couple stress and cross-diffusion parameters (Dufour and Soret), on a ternary hybrid nanofluid flow [Formula: see text] across a convectively heated flat plate. The analysis takes into account non-Fourier heat flux and irreversibility. The governing equations are converted into a set of ordinary differential equations using appropriate similarity transformations, and then the bvp4c solver is used to find solutions. Outcomes are provided for two instances, that is, nanofluid ([Formula: see text]) and ternary hybrid nanofluid [Formula: see text] The fluid velocity is found to be negatively correlated with the couple stress parameter rises ([Formula: see text]) which is one of the major findings in this study. Within the range of [Formula: see text] it is seen that the friction factor exhibits a gradual increase with a rate of 0.02878 (in the case of nanofluid flow) and 0.038083 (in the case of ternary hybrid nanofluid flow). Additionally, when the Dufour number is between 0 and 0.6, the Nusselt number exhibits a discernible decrease of 0.27678 (in the case of nanofluid flow) and 0.26428 (in the case of ternary hybrid nanofluid flow). Furthermore, at [Formula: see text] (the Sherwood number), the Sherwood number drops at a rate of 0.0786 (in the case of nanofluid flow) and 0.05592 (in the case of ternary hybrid nanofluid flow). It has been observed that an increase in the chemical reaction parameter [Formula: see text] lowers the fluid concentration. It is observed that the Sherwood number increases at a rate of 0.037654 (in the case of nanofluid flow) and 0.037661 (in the case of ternary hybrid nanofluid flow) when [Formula: see text].
