System design and Flow simulation of a Blowdown Sliding-block Supersonic Wind tunnel

Abstract

This study presents the design, simulation and performance evaluation of a blowdown sliding-block supersonic wind tunnel having a test section sized 20 × 20 cm, capable of operating in the range of Mach number from 2 to 4. This sliding-block mechanism allows precise control of Mach number by adjusting the nozzle throat area. A computational fluid dynamics (CFD) simulation was performed at Mach 2.5 to evaluate the flow characteristics. The 3D geometry was simplified into a 2D axisymmetric model, and a structured quadrilateral mesh was generated using ANSYS Meshing. The density-based solver in ANSYS Fluent with the RNG k-epsilon turbulence model was employed to capture supersonic flow phenomena. Results demonstrate that the system achieves the target Mach number with a relative error of less than 0.4%, indicating excellent flow quality, and no major observed shock wave. The study validates the wind tunnel's performance, providing a reliable foundation for experimental aerodynamic testing.