Evaluation of Thermal Mixing in T-Junctions Using Computational Fluid Dynamics (CFD)

The thermal mixing process in T-junctions presents a significant challenge in optimizing heat transfer and temperature distribution, especially in systems involving both hot and cold fluids. The problem addressed in this study was to understand how variations in inlet velocities, pipe diameters, flow rates, and turbulence models affect heat transfer and thermal mixing. The solution was achieved by performing detailed CFD simulations, evaluating these factors under controlled boundary conditions of 40 m/s hotinlet velocity, 30 m/s cold inlet velocity, and a 15 K temperature difference between the main and branch pipes. The results reveal that higher inlet velocities enhance thermal mixing, with outlet temperatures increasing from 223.382 K to 325.975 K as hotinlet velocity increases from 20 m/s to 40 m/s. Increasing the hot inlet diameter from 2 cm to 4 cm improves temperature distribution, raising the outlet temperature from 325.95 K to 329.797 K. The introduction of dual hot inlets further enhances the temperature to 329.797 K. Comparative analysis of turbulence models (k-ω and k-ε) indicates that the k-ω model provides more uniform temperature distribution. Moreover, variations in flow rates show that higher flow rates in the main pipe led to an outlet temperature of 312 K, while higher flow rates in the branch pipe reduced the outlet temperature to 305 K. This research offers critical insights for optimizing T-junction designs, improving thermal mixing, and enhancing heat transfer in industrial applications.