Experimental Research on the Aerodynamic Performances of 2-D Lobed Exhaust Ejector Systems

Abstract

Experimental research for seven exhaust ejector system combinations, including four two-dimensional (2-D) lobed nozzles and three 2-D mixing tubes, has been conducted to investigate the effect of the lobe structure on the aerodynamic performances of the ejector systems. Test results show that: 2-D eligned lobed nozzles have better pumping and mixing enhancement abilities than the 2-D staggered lobed nozzles, but they also cause bigger pressure losses; the 2-D lobed nozzle with equal lobe width have better aerodynamic performances than the 2-D lobed nozzle with bigger inner lobe width. 2-D aligned scalloped lobed nozzle has the best pumping and mixing enhancement performances, but it also has the biggest pressure loss coefficient. Among the tested combinations, the combination of 2-D staggered lobed nozzle with equal lobe width and 2-D mixing tube with multiple-ring cooling structure has the best combined aerodynamic performances.

Research on the vortical and turbulent structures in the lobed jet flow using laser induced fluorescence and particle image velocimetry techniques

“…Such a device had been known since the earliest days of jet engines and has received considerable attention with the aim of reducing jet noise since the 1960s. More recently, use of a lobed nozzle has emerged as an attractive approach for mixing the core and bypass streams of turbofan engines in order to improve propulsion efficiency, reduce the specific fuel consumption (SFC) and suppress the emission of infrared radiation (Power et al 1994, Presz et al 1994, Hu et al 1996. Lobed nozzles/mixers have also received attention for use in supersonic ejectors to reduce jet noise at take off and landing of aircraft as well as in combustion chambers for enhancing mixing between fuel and air Presz 1993, Smith et al 1997).…”

Jet impingement heat transfer from lobed nozzles

“…Many studies have been conducted to enhance mixing, such as the works of Tilman and Presz [23], Power et al [24], Presz et al [25], Hu et al [26] or Smith et al [27]. Research into the physics of mixing within these devices has been the subject of numerous works.…”

Experiments and Large-Eddy Simulations of Lobed and Swirling Turbulent Thermal Jets for HVAC's Applications

“…The vortex enhanced mixing has become one of the highly targeted research areas in recent years (Depuru et al, 2015). Many investigations are carried out to improve the air mixture, like the works published by Tilman et al (1993); Presz et al (1994); Power et al (1994); Hu et al (1996) and Smith et al (1997) to name a few. Paterson et al (1982) have been among the first to measure the turbulent characteristics and velocity of a lobed diffuser.…”