Automated design optimization of a U-shaped diffuser

An automatic computational optimization of a U-shaped diffuser with a 180° turn is performed with the objective of reducing the flow distortion at the outflow. Both laminar and turbulent flow conditions are examined using uniform velocity and fully developed inflow conditions. The design variables are the semimajor and semiminor axes of the diffuser cross-section at the midpoint of the 180° turn. The optimal designs are compared with the baseline design which used a circular cross-section throughout. The optimal designs show uniform improvement (reduction) in distortion at the exit by reshaping of the cross-section at the midpoint of the 180° turn. The principal characteristic of all optimal designs is an over-expansion of the flow (i.e. the cross-sectional area at the midpoint of the 180° turn is greater than the cross-sectional area at the exit).