Experimental and Numerical Investigation of Impinging Jet Flow in Square Ducts Intersecting at 90 Degrees

An experimental and numerical investigation has been conducted on flow through two square ducts with a 2:1 hydraulic diameter ratio joined at a right angle. Measurements of the velocity field were acquired using a laser Doppler velocimeter at various planar locations throughout the ducts at a nominal Reynolds number of 68,000. Pressure drop measurements were taken for 3 Reynolds numbers between 46,000 and 93,000. Computational fluid dynamics (CFD) analyses were performed using STAR-CD to determine how well the experimental data could be predicted using the k-{var_epsilon}, k-{var_epsilon} RNG, k-{var_epsilon}Chen, k-{var_epsilon} quadratic, k-{omega}, and Spalart-Allmaras models. The results show that there are distinct differences in the CDF results. The standard k-{var_epsilon} model overpredicted the loss coefficient by 4% and underpredicted the exit swirl magnitude by 43%. The best predictor of the swirl decay was found to be the k-{omega} model, which adequately followed the data throughout the entire geometry and underpredicted the exit swirl by 16%. The best overall model was found to be Spalart-Allmaras, which overpredicted the loss coefficient by 2% and underpredicted the exit swirl magnitude by 40%