THE EFFECT OF CORNER RADIUS ON THE ENERGY LOSS IN 90 ° T- JUNCTION TURBULENT FLOWS

An extensive numerical parametric investigation of the turbulent flow in 90 ° T-junctions with sharp and rounded corners is under way aimed at quantifying the energy losses and the size and strength of the recirculating region in the branch pipe. The parameter that is being investigated is the radius of curvature of the corner of the junction and so far simulations have been carried out for an inlet pipe Reynolds numbers of 32,000, to be later extended to the range between 5,000 and 40,000, for flow rate ratios of 0%, 20%, 40%, 50%, 60%, 80 % and 100 % (ratio between the flow rates in the branch and inlet pipes). The previous work of Paál et al. [8] on this flow for a sharp corner was aimed at validation by comparing the results of simulations done with various turbulence models with the detailed experimental data of Maia et al. (1998). Following [8], it was decided to perform the present calculations using a modified version of Menter’s [9] model, the shear-stress transport (SST) model, which performed equally well as or even better than the full Reynolds stress model at a considerably lower cost. All the calculations were carried out with the commercial code ANSYS CFX 10.0. The results show that increasing the radius of curvature of the corner reduces the total energy loss especially because of the reduction in the branch flow loss related to flow separation