Large Eddy Simulations LES were conducted to study single-phase flow in a geometry with a bluff body inserted into a long pipe as a simplified case of a more complex separator. Two configurations, without bluff body and without swirl generator, were considered for comparison. While studies on swirling flows inside pipes do exist in the literature and plenty of information is available, the present simulations address the case where the swirling flow interacts with a bluff body which was scarcely considered hitherto. The results showed a persisting core flow reversal till the bluff body location under the flow conditions considered. The swirling flow has a Rankine-vortex structure with more turbulence at its core. The bluff body undergoes the effects of recirculation zones at its front and wake regions which affect the corresponding drag and lift forces considerably. The swirl number decays from 1.5 to unity close to the bluff body. No dominant frequency was noticed in the core region. All these findings represent a starting point for an optimization work on the appropriate location and shape of the bluff body for the real separator.
