Design And Optimization Of A Three-Dimensional Small Wind-Tunnel Contraction Section
Abstract
In this article, A contraction has been designed, manufactured at the Mechanical Engineering Department at Baghdad University - College of Engineering. The theoretical study was accomplished by ANSYS workbench 15.0 and using K-Ԑ turbulence model to simulate turbulent flow in a 3-D contraction section of small low subsonic wind tunnel. A sixth-order polynomial equation had been adopted with a specified boundary conditions to represent a smooth contraction wall profile shape. Seven inflection points are chosen to give seven different contractions. An experimental low-speed wind tunnel of test cross section area (0.45x0.45 m2) and new contraction section was built and tested for maximum velocity at test section 20 m/s. Boundary layer thickness, static pressure and secondary flow and the maximum uniformity are considered as optimization parameters. Numerical results show that boundary layer thickness decreases, variation in wall normal velocity components at the test section inlet increases, and probability of flow separation increases as the inflection point moves towards the contraction outlet. The optimized contraction is investigated computationally and experimentally. The experimental results of contraction compared well with the computational code ANSYS workbench 15.0 results.
