Numerical Study of Induced Condensation upon Mixing Flows of Water-stream Flow in a Tee-Junction Pipe

Abstract

Tee-junction is a device used in pipes to transfer, mixing of two dissimilar fluids of different parameters or either same type with varying parameters. The design of the tee-pipe affects its function. The present paper introduces a numerical study of two-phase flow mixing in a T-junction pipe. Water liquid streams in the horizontal main pipe of a T-junction while saturated steam is drawn from the other pipe branch (it lies in a vertical plane). That results in water liquid and steam mixing with steam condensation, and the mixture is directed to exit from the main pipe. The computational model is validated first with the experimental data for a single-phase flow. Two junction angles 90 o and 45 o between the main pipe and branched pipes are utilized for the T-junction. Different mass ratios for water liquid and steam are examined in the main pipe and branched pipes. Also, various turbulence models are utilized to select the best suitable model for predicting such flows. The comparison ensured the superiority of the realizable k-ɛ model for the present two-phase flow mixing. The obtained results reveal that the T-junction pipe with a junction angle of 45 o achieves improved operational performance compared to the pipe with the junction angle of 90 o . This result shows that the incline of the branch pipe could induce more heat transfer on the area of the T-junction, which inevitably could condensate more steam from the branch pipe. The T-junction pipe with a 45 o angle can condense all the mixed steam in shorter pipe lengths with lower pressure loss at the same operational conditions compared to the 90 o junction angle pipe. Moreover, for constant mass flow rates in the main and branched pipes, an increase in their diameters results in a remarkable enhancement of steam condensation.