Numerical Investigation of the Secondary Swirling in Supersonic Flows of Various Nature Gases

Despite the application of vortex tubes for cooling, separating gas mixtures, vacuuming, etc., the mechanism of energy separation in vortex tubes remains an object of discussion. This paper studies the effect of secondary swirling in supersonic flows on the energy separation of monatomic and diatomic gases. The approach used is a numerical solution of the Reynolds-averaged Navier-Stokes equations, closed by the Reynolds Stress Model turbulence model. The modelling provided is for a self-vacuuming vortex tube with air, helium, argon, and carbon dioxide. According to the results of the calculations, the effect of secondary swirling is inherent only in viscous gases. A comparison was made between obtained total temperature difference, the level of secondary swirling and power losses on expansion from the nozzle, compression shocks, friction, turbulence, and energy costs to develop cascaded swirl structures. Our results indicate that helium and argon have the highest swirling degree and, consequently, the highest energy separation. Moreover, it can be concluded that the power costs on the development of cascaded vortex structures have a significant role in the efficiency of energy separation.

Combustion in a supersonic flow using a pylon equipped with a plasma actuator

Plasma-assisted combustion approach is well known for organizing stable ignition and flame holding in supersonic flows in model scramjet combustion chambers. In this work, a new geometry of pylon equipped by electrodes relative to developed earlier was proposed and experimentally investigated. Stable ignition and flame holding were obtained over a wide range of fuel flow rate and discharge currents. Reducing of the energy input in comparison with the previously considered configurations was also demonstrated.