Numerical and Experimental Study on the Transitional Heat Transfer of a Vertical Tall Square Aluminum Tube

The purpose of this study is to develop turbulence-enhanced heat dissipation fins for natural convection from a large-scale vertical square tube, with the expectation of future applications in large-scale electric devices such as the cooling electric vehicle charging poles.To provide reference data for future research, this study first involves conducting experiments to measure the total surface heat rate of a closed aluminium square tube under a temperature difference of approximately 55C.The experimental data will then be compared with various turbulence models.Additionally, the simulation will compare the velocity and temperature at the inlet, middle, and outlet sections of the tube, using the LES model as a benchmark.The results show that the k -kl - model most closely matches the LES model in terms of velocity and temperature distribution across all sections.Although the LES model differs from the experimental data by 13%, the k -kl - model remains the most consistent with the LES model in terms of the total surface heat transfer rate.These results will provide significant guidance for optimizing fin spacing and structural design for large-scale electric devices in future studies.