Numerical Analysis by Computational Fluid Dynamic Simulation of Fluid Flow in A T- Junction Marwa S. Luaibi 1 , Mohammed A. Abdulwahid 2 {Marwa.salman1988@gmail.com 1 / Marwa.salman@stu.edu.iq 1 , mohw2016@stu.edu.iq 2 } Engineering Technical College, Southern Technical University, Iraq¹ʼ² Abstract. The flow in a T-junction is very important in industrial and equipment. Prediction of the loss coefficient and velocity profile of fluid with the turbulent incompressible flow in T-junction pipe for non-symmetrical dividing and non-symmetrical combining helps to understand this type of fitting. The angle of the tee is 90⁰, sharp edge, the area ratio is equal to one and Three-dimensional the specification of geometry at steady state. The model of turbulent uses the stander k- and solving the Navies- Stocks equation by finite volume method in the SIMPLE algorithm in ANSYS FLUENT R1 2020. Comparison of the numerical results with previous work to study the effect of the flow rate ratio with different Reynolds numbers in the range (3000-30000). The results show the loss coefficient is independent of Re numbers. The non-symmetrical dividing the maximum flow move in the straight pipe when the change flow rate ratio to (0.8) forced the fluid to move in the branch and formation high vortex and recirculation. The non- symmetrical combining the high velocity in outlet branch with small eddies especially increased at a flow rate ratio (0.8). Keywords: T-junction, non-symmetrical, turbulent flow, loss coefficient, flow rate ratio. 1 Introduction The networks and industrial contain several pipes and T-junction. The T- junction consider is the most common complex section of networks pipe that is mainly employed for the transportation and supply of gases and liquids. The T-junction is utilization to merge (combining) flows from branch pipes to the main pipe. Separate (dividing) the flow from the main pipe to several branching pipes. as shown in Fig 1. Fig 1. Various possibilities of fluid in the junction. IMDC-IST 2021, September 07-09, Sakarya, Turkey Copyright © 2022 EAI DOI 10.4108/eai.7-9-2021.2314888