Numerical study of heat and mass transfer in a wavy porous enclosure with thermosolutal sources and a cold block

Purpose The purpose of this paper is to numerically optimize coupled thermal and solutal transport while minimizing entropy generation in a wavy porous container with partial heating and an internal cold block, filled with a non-Newtonian ternary hybrid nanofluid (THNF). The novelty of this study lies in the combined analysis of thermosolutal convection in a wavy porous enclosure with an internal cold block, revealing the coupled effects of geometry, porous medium and localized cooling on heat and mass transfer. Design/methodology/approach A steady-state numerical model is developed based on the governing equations of mass, momentum, energy and species transport for a non-Newtonian THNF. The finite difference method (FDM) is used to discretize and solve the coupled nonlinear equations. A comprehensive parametric study is conducted to examine the effects of heater size, Lewis number and thermophysical parameters on flow topology, thermal and solutal transport characteristics, entropy generation and Bejan number. Findings The results reveal a critical trade-off between thermal enhancement and system irreversibility. While increased system energy promotes convective mixing, enlarging the heater size significantly degrades performance, resulting in reduced heat and solutal transfer, along with an increase in entropy generation. In addition, an increase in the Lewis number leads to a reduction in heat transfer (1.09%) and total entropy generation (48.54%), while enhancing the solutal transfer (75.57%). Originality/value The findings provide new physical insights and practical design guidance for optimizing heat–mass transport and irreversibility in advanced thermal management systems relevant to electronics cooling and compact reactor technologies.