Strategic Project - LA 22 - 2011-2012

Funder

Organizational Unit

Publications

Aerodynamic control of the mixing of confined, plane and co-axial jets

Publication . Neves, Fernando Manuel da Silva Pereira das; Barata, Jorge Manuel Martins

Turbulent mixing of confined coaxial jets is a complex dynamic process with many practical applications such as ejectors, jet pumps, industrial burners, jet engine combustion chambers, gaseous nuclear rockets, mixing chambers, afterburners, and turbofan engine mixing chambers. In this latter applications the confinement is also of basic interest because it involves a certain interacting turbulent flow phenomena, the details of which are not yet fully understood quantitatively (Ahmed and Sharma, 2000). There have been studies of different geometric and operating parameters on the turbulent mixing process of confined coaxial jets with different motivations. While a wide range of diameter ratios has been investigated in the past, no work was reported on diameter ratios below 2, which is the case with many low bypass turbofan engines with bypass ratios of 0.3 and less. Only Ahmed and Sharma (2000) reported recently detailed LDV measurements of mean and turbulence components of velocity as well as the total and static pressures over a range of velocity ratios with relevance in the present context. In their work they analyse the influence of velocity ratio on the turbulent mixing process, but there are many other parameters which influence the turbulent mixing process. This research is dedicated to the study of the turbulent mixing of parietal jets without any generated effect of swirl and without the presence of bluff bodies. The major objective was to design mixing control strategies using purely aerodynamic tools. Following a work on axisymmetric geometries, a two-dimensional geometry was adopted to study the influence of geometric and initial parameters to control the flow: confinement, inclination angle and turbulence intensity of the outer flow.

2012Doctoral thesis

Open access