Correlation development and parametric investigation for local pressure drop of mixing t-junction using response surface methodology

The behavior of mixing flow within a T-junction is highly intricate in energy transport systems. A 3D numerical model for the T-junction was established, the flow and thermal characteristics were analyzed in detail. The response surface methodology was employed to investigate the interactive effects of angle, velocity ratio, and diameter ratio on the local pressure drop coefficients of the T-junction. The corresponding correlations for KAC and KBC were developed and validated. It could be observed that, compared with the inlet pressures of the main and branch tubes, the static pressure in the downstream section of the main tube drops sharply. A symmetrical vortex can be found at the entrance of the downstream in main tube. Three key parameters including cos ?, U*, and D* all have a significant effect on KAC and KBC, and the interactions of cos ? with U* and D* are significant for KAC, while for KBC, the interactions among the three parameters are all significant. Furthermore, the developed correlations demonstrate high accuracy in predicting the local pressure drop coefficients. To validate their reliability, two additional tests are conducted. The discrepancies between the simulated and predicted values of KAC are merely 1.46% and 7.39% for the first and second tests, respectively, while those for KBC are limited to 9.7% and 7.02%, respectively.