Wind tunnels are test devices used in aerodynamic experiments to understand the effects of air moving through solid objects. Wind tunnels are often used to provide a steady and controlled flow of wind to replace natural winds and to test new models of spacecraft, aircraft and vehicles, and some wind tunnels have enough room to inspect full-size cars.
A small wind tunnel system has been acquired and requires re-design and testing. These works follow on the ENG470 work by Mr Ibrahim Noor Izham, who undertook the initial study that analysed the functionality and limitations of the existing wind tunnel. However, the conclusion of the works shows the current wind tunnel does not have the capability to meet the requirements of Murdoch University.
Therefore, this project aims to design and construct a new open return wind tunnel system for Murdoch University, which has been designed to achieve 20m / s in the test section with expected low turbulence intensity level. Making it available for Murdoch University research and education purposes, for example, research particular emission from biochar-amended soil, low-speed aerodynamics experiments (ENG 339: Wind and Hydro Power Systems: testing aerofoil and wind turbine models). In order to implement these goals, a very detail design was carried on using theoretical modelling and CFD simulations. Moreover, flow stabilization and control are also performed by using a honeycomb and screens; all of these are optimized to produce low turbulence levels in the test section. Furthermore, the axial fan with a VFD for this wind tunnel project was delivered at the end of March 2019, to assist the subsequent wind tunnel project, an experiment was conducted on 25th May 2019 to study the relationship between wind flow speed generated by the axial fan with different fan speed in RPM.
The report has addressed the dimension of the new wind tunnel design by theoretical modelling method. Base on this dimension of the wind tunnel design, an AutoCAD modelling and a CFD simulation is conducted to investigate the turbulence intensity level in the test section. The results show that when the wind tunnel is operated at a wind speed of 20 m / s, the turbulence intensity of the test section is less than 3%. The fan test results show that the maximum wind speed produced by the axial fan is 12.97 m / s, which is much lower than the expected speed of the fan section of 15.405 m / s. The reason is that the vibrations of the fan test structure affect the wind speed measurement of the Pitot tube. In addition, after completing the construction of the entire wind tunnel, the contraction cone will accelerate the flow through the wind tunnel to meet the expected speed
