Arash kazemian

Thank you for your response. I used a structured mesh throughout the entire model. Regarding the temperature legend, it ranges from 40°C to 50°C, so the temperature difference is not that high, and we can assume constant properties. I have some questions:

1. If Re is less than 2300, should I consider laminar flow or turbulence? Since the model includes some branches and not only a straight tube, how can we determine if it is laminar or turbulent? If it is turbulent, which model would be most suitable for this model - k-e, k-w, or...?

2. I used fully developed flow at the inlet, yet the temperature contour is still like the last figure. Is this contour reasonable or not?