Thermo-fluid characteristics and second law analysis of an inclined two-fluid system with variable surface roughness

Abstract

The present numerical study focuses on the analysis of thermodynamic characteristics of an inclined two-fluid system (Al2O3-water and CuO-water nanofluids) having a heat conducting partition wall of variable surface roughness with constant geometric orientation. A further level of thermal control that results in an optimum system orientation for greater thermo-physical transport along with less entropy generation and thermal optimization is explored by examining the effect of system inclination. Based on the second law of thermodynamics, the quantitative results include the variation of average Nusselt number, average fluid temperature, average entropy generation, and average Bejan number for a wide range of Rayleigh number and inclination angle. Current study realizes that the mean quantitative properties of the system are significantly affected by the change of Rayleigh number and inclination angle, despite having a weak dependency on the partition roughness. The variation of average Bejan number with Rayleigh number assumes a reverse trend compared to the same for average Nusselt number and entropy generation and decreases continuously as the flow circulation strengthens. The rate of thermal transport is significantly regulated by the system orientation. Each Rayleigh number conforms to a critical angle of the system inclination for highest thermal transport and entropy generation.