Design and Development of Low Subsonic Wind Tunnel for Turning Diffuser Application

In practice, it is basically difficult even with controlled measurement environment to acquire a steady, uniform and fully developed flow. The flow entering diffuser was severely distorted despite a sufficient hydrodynamic entrance length already introduced. This was mainly due to the imperfect joining of duct and the abrupt change of the inlet cross-section applied. In this study, several basic features of a low subsonic wind tunnel, i.e. a centrifugal blower with 3-phase inverter, a settling chamber, screens and a contraction cone, are designed and developed for a turning diffuser application in order to improve the flow quality. The flow profiles are examined using Pitot static probe at five measurement points within the range of inflow Reynolds number, Rein= 5.786E+04-1.775E+05. The steady, uniform and fully developed turbulent flow profiles with an average deviation with theory of about 3.5% are obtained. This proves that a good flow quality could be produced by means of incorporating some basic features of a low subsonic wind tunnel to the system.