Numerical simulations of a lobed fuel injector

Abstract

Numerical modeling of the nonreactive mixing processes associated with a lobed fuel injector in a coflowing air stream is presented. The lobed fuel injector is a device which generates strong streamwise vorticity, producing locally high strain rates which can enhance the molecular mixing of reactants while delaying ignition in a controlled manner. Vortex element modeling is used to simulate flow field evolution and fuel element mixing characteristics for this lobed fuel injector. Quantitative predictions for vorticity generation and qualitative results for streamwise rollup compare well qualitatively with recent experimental investigations of this flow field ͓Smith et al., Phys. Fluids 9, 667 ͑1997͔͒. Parametric studies of the effects of lobe amplitude-to-wavelength ratio, lobe angle, and lobe shape for given flow conditions suggest that geometrical features may be optimized to enhance mixing and control reaction processes.

Passive mixing control via lobed injectors in high speed flow

“…The effect of this skewing on the ow evolution was determined by making a comparison of experimental observationssuch as those in Fig. 6 with numerical simulations of the lobed injector ow eld, using the vortex element method previously used and described in detail by Strickland et al 2 Details on the present simulation may be found in Ref. 26.…”

“…The lobed injector shapes, incorporating vertical or essentially vertical side walls, were designed on the basis of their potential for vorticity generation and rollup as predicted by an incompressible simulation of the ow eld. 2 Lobed mixers with vertical side walls are similarly observedto enhancestreamwise vorticity generation. 5¡9 All three injectors were fabricated of aluminum using an electrical discharge machining (EDM) device, and all three had the same injectant gap width (0.381 mm) and wall thickness (0.584 mm).…”

Passive Fuel-Air Mixing and Emissions Control Via Lobed Injectors

“…4a. Injector B2 was an alternative fuel injector design, based on the results of numerical simulations of the lobed injector flowfield, 13 which showed a propensity for this shape to generate stronger streamwise vorticity. The lobed injectors were all constructed of aluminum using electricdischarge machining.…”

Experimental and numerical study of mixing characteristics of a rectangular lobed mixer in supersonic flow

“…In addition, several numerical studies have been performed to study the three-dimensional flow field downstream of the lobed mixer. Originally, a steady RANS approach in conjunction with a turbulence model (38)(39)(40)(41)(42) and a vortex-element approach (43) were used to calculate lobed mixer flows, and the effect of boundary conditions on the numerical results were also considered in these studies (39)(40)(41) . Subsequent studies with regard to mixing characteristics of lobes have simulated multiple or realistic lobed nozzles using a large-eddy simulation (LES) approach (44,45) .…”