Abstract: T-junctions are widely used to facilitate the mixture of two fluids at different temperatures and in most cases, different velocity also. Temperature of the mixture at the outlet of the main pipe undoubtedly plays a significant role in all the industries where T-junctions are implemented as their main intention is to get reduced temperature of the fluid. This paper deals with the three main cases which are expected to rather have a significant impact on the outlet temperature viz. short tee, increased velocity ratio and long tee respectively.