Effect of expansion angle on turbulent swirling flow

摘要

This paper presents the numerical study ofswirling turbulent flow through different expansionangles which have many practical applications in gasturbines, combustors, etc. The governing differentialequations, which corporate k-#epsilon# turbulencemodel closure, are solved by a control-volume basediterative finite difference technique. Predicteddistribution for the mean velocities, turbulencekinetic energy and streamline plots are presented.Computations are done for different swirl numbers upto 1.5 and for different expansion angles between 30deg and 9O deg. With the increase of swirl strength,secondary on-axis recalculation is observed inaddition to the primary corner recalculation. Swirlproduces larger turbulence kinetic energy andenhances mixing rate, thus requiring shortercombustor length. For any particular swirl strengthbeyond the transition value, at smaller expansionangle, higher turbulence kinetic energy generationand consequently better mixing is found. The computedresults have been found to be comparable to the available experimental data.