RANS SIMULATIONS OF TURBULENT AND THERMAL MIXING IN A T-JUNCTION

• Published in: Mechanika (Kaunas, Lithuania : 1995) Vol. 19; no. 3; pp. 277 - 282
• Main Authors: Aounallah, M., Belkadi, M., Adjlout, L., Imine, O.
• Format: Journal Article
• Language: English
• Published: 01-01-2013
• Subjects: Computational fluid dynamics; Computer simulation; Fluid flow; Pipe; Tensors; Turbulence; Turbulent flow
• DOI: 10.5755/j01.mech.19.3.4663
• EISSN: 2029-6983
• ISSN: 1392-1207

The turbulent and thermal mixing in a horizontally oriented T-junction is investigated numerically. The objective of the present study is to determine the mixing length in a T-junction where homogeneous temperature distribution is established in the cross section. A steady state three-dimensional turbulent flow is considered with a Reynolds number of 0.7 x 10(5) at the inlet of the main cold pipe. Grid is generated in a stretched manner so that strong gradients near the wall regions are accounted for as required. Four turbulence models are tested to provide closure for the Reynolds stress tensor: the k-epsilon standard, the k-omega standard, the k-omega SST and the RSM models. For all simulated cases, good qualitative agreement is obtained. Quantitative comparisons show that the standard k-epsilon and the RSM models give too low or high predictions, whereas both k-omega models are reasonably close between them. It is found that a length of 80 inch is enough to get homogenous temperature if a tolerance of 1 degree C is considered. Further simulations on a longer pipe are strongly encouraged to assist in elucidating the length mixing determination.