Numerical Analysis of Swirl Effects on Conical Diffuser Flows

Eron Tiago Viana Dauricio, Cláudia Regina Andrade

Abstract


The present paper focuses on the effect of swirl on important parameters of conical diffusers flows such as static pressure evolution, recirculation zones and wall shear stress. Governing equations are solved using a software based on the finite volume method. Moreover, turbulence effects are taken into account employing the k-ε RNG model with an ennhaced wall treatment. The Reynolds number has been kept constant at 105, and various diffuser geometries were simulated, maintaining a high area ratio of 7 and varying the total divergence angle (16°, 24°, 40°, and 60°). Results showed that the swirl velocity component develops into a Rankine-vortex type or a forced-vortex type. In the former, swirl is not effective to prevent boundary layer separation, and a tailpipe is recommended to allow a large-scale mixing to enhance the pressure recovery process. In the latter case, boundary layer separation is prevented but an intermediary recirculation zone appears. Higher pressure recovery is attained at the exit of the diffuser with swirl addition, without the need of a tailpipe. Results also suggest that there is exists an imposed swirl intensity where the energy losses are minimum thus leading pressure recovery to an optimum level.

Keywords


Static pressure recovery; Wide-angle diffuser; Swirl intensity; Radial pressure gradient; Intermediary recirculation zone.

Full Text:

PDF


DOI: http://dx.doi.org/10.5028/jatm.v9i1.674

Refbacks

  • There are currently no refbacks.
';



Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.