Study on the effect of various parameters on flow development behind vane swirlers

This study mainly focuses attention on arriving at best vane angle from aerodynamic aspects for the combustion applications. As there are large number of flow and geometric parameters involved arriving at the best design by experimental methods is rather difficult compared to CFD analyses. The important geometric parameters are vane angle, vane numbers and hub to tip ratio. The flow parameter involves the selection of appropriate turbulence model for the prediction. The uniqueness of this study is in arriving at the best vane angle using appropriate turbulence models for both weak and strong swirl. To this end experimental and numerical studies have been carried out. It is found that no single turbulence model is able to handle both weak and strong swirl. From this study it is concluded that for weak swirl standard k-ε model is sufficient whereas for strong swirl one has to resort to Reynolds stress model. The characteristics of swirl flow are evaluated by means of size of the recirculation zone, mass trapped in the recirculation zone and also the pressure drop. Over the range of vane angle investigated the best vane angle is found to be 45°.