Better swirl generation by using curved vane swirlers

In this investigation, several curved vane swirlers have been tested and compared with flat vane swirlers for a blockage ratio of 0.538. For each swirler (except for two), pressure drop and flow field measurements have been made in the issuing free swirling jet in order to determine the size and other aerodynamic characteristics of the induced recirculation region. Hot-wire anemometry and a five-hole pressure probe have been used for the measurements. Results indicate that the size of the induced recirculation region increases with increasing vane outlet angle in the case of curved vane swirlers similar to flat vane swirlers. Measurements also show that for the same vane outlet angle, the pressure loss through a swirler can be reduced around 60-70 percent by using curved vanes; in addition, the resulting recirculation region becomes larger and stronger.