Simulation And Analysis On Fluid Flow Field In Tee Based On FLUEND Soft

In petro-chemical industry, Assembly of pipeline is a large and complicated works. Therefore, the invalidation of pipeline will no doubt cause the great financial loss and safety accident to company. So it has important significance in how to avoid pipeline invalidation in piping design.Tee is widely applied in the pipline system of petro-chemical industry and nuclear power plant. Tee, in which the hot and cold fluid mixed with temperature fluctuations,will cause thermal stresses and subsequent fatigue cracking of the pipeline. So it is important to predict the pressure velocity and temperature field in the tee.This paper will simulate the changes of the parameters like temperature, pressure and speed etc by using the Fluent soft k-ε model which based on the finite volume method to study on hot and cold flow mixing process. Through regulating the change of fluid with time of the flow of hot and cold flow, A situation of turbulence in different3-d spaces and conbining the flow of cold and hot flow mix in Tee was given, through which we can analysis the structure, temperature and pressure distribution on different cases. The simulation results are as follows:With the increase of branch diameter, the proportion of jet flow area is increased. In the down stream of the branch can forms a large vortex. The mixture of both mian and branch flows will accelerated in the narrow channel under the vortex. The mixture in deflecting jet is better than wall jet.When there is an elbow before Tee bus pipeline, speed obviously stratified in elbow, and the flow came to instability. It also leads to increase of pressure loss, lower efficiency, and the thermal stress near the junction, the grow larger.When the velocity ratio is1(between the main and branch), diameter ratio is3, jet angle is45°, the distance of mixed flow is the shortest, the flow shape stabilize faster. The impact force and pressure distribution of the pipe wall will also be decreases. Accordingly, inflow angle at45°is the best angle.With the increase of branch diameter, the area of pressure-increase is also enlarged. This pressure-increase area gradually transits from the branch to the main pipe. Then the pressure in the down area of Tee connection is smaller. There is a larger vortex after the mix of main and branch.The simulation study of fluid flow in the area of the connection before the mix shows: there is an obvious speed delamination in the area of elbow which causes the instability after the mix. The exist of elbow only increases the pressure loss and low enfficiency. and also increase thermal stresses near the connection after the mix.