The Effects of Trailing Edge Modification in a Blade Cascade upon Radiated Sound

초록

It is addressed that the turbulent broadband sound power from a sirocco fan can be modeled effectively by the trailing edge (T.E.) noise, which is usually influenced by inflow turbulence, separation, and boundary layer thickness on the blade. The design parameters such as solidity (c/s) and stagger angle were specified to comparethe noise levels and their spectra for various T.E. models because a separation and a slip velocity are strongly affected by them along with the flow coefficient. This paper reports the effects of stagger angle upon the trailing edge noise for various trailing edge shapes. It is believed that the serrated trailing edge models contribute to the break-up mechanism for organized convection vortices, thereby reduce the overall noise level for tested cases of stagger angles.