Advanced IR suppressor design using a combined CFD/test approach

Power, Greg D.; McClure, Mark B.; Vinh, Daniel B.

doi:10.2514/6.1994-3215

Cited by 19 publications

(10 citation statements)

References 5 publications

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“…4 Former researchers, such as Kozlowski and Larkin, 5 Rowe and Kuchar, 6 Kozlowski and Kraft, 7 Kuchar, 8 Shumpert,9 and Anderson and Povinelli, 10 focused on systematically studying the influence of geometric and aerodynamic parameters (such as lobe shape, number, height, rise/fall angle and Re, velocity/temperature/pressure ratio, etc.) on performance of lobed nozzles.…”

Section: Introductionmentioning

confidence: 99%

Numerical research on the mixing mechanism of lobed mixer with inlet swirl in linear radial distribution

Lei

Zhang

Zhu

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part A:

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A detailed numerical simulation is presented to investigate the effects of inlet swirl and its radial distribution on the mixing mechanisms of a turbofan mixer with 12 lobes, by using the commercial ANSYS CFX solver and k-! SST model. The core-to-bypass temperature ratio and pressure ratio were set to 2.59 and 0.97, respectively, giving the Mach number of 0.66 and bypass ratio of 2.65 at mixing nozzle outlet. In the core inlet, the swirl angle was raised from 0 to 30 in a uniform or linear radial distribution manner. The inlet swirl and its radial gradient did enhance the development, interaction, and dissipation of the vortices downstream of lobed mixer, resulting in accelerating the lobed jet mixing. When the inlet swirl was less than 20 , the total pressure and thrust loss increments of lobed jet were acceptable and no more than 0.26% and 1.57%, respectively, compared with the baseline case. The results also showed that the three-dimensional separation bubble on center-body and the backflows along jet axis at the rail of center-body, resulting from the swirling flow between lobes' trough and center-body, were the dominant sources of total pressure and thrust losses for all cases with inlet swirl. And, reasonable radial distribution of inlet swirl could inhibit the aforementioned 3D separation and backflow, and thus limited the increment of jet mixing loss favorably.

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Section: Introductionmentioning

confidence: 99%

Numerical research on the mixing mechanism of lobed mixer with inlet swirl in linear radial distribution

Lei

Zhang

Zhu

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Mixer lobes introduce large scale streamwise vortices that enhance mixing between hot core gases and cold bypass air in the exhaust nozzle, with a resulting increase in net thrust [1], a reduction in fuel consumption [2], a reduction of jet noise [3], and,, in some cases, reduced infrared signature [4]. These large-scale vortices arise due to the radially deflected flows from the lobes that cause the convoluted shear layer to rotate.…”

Section: Introductionmentioning

confidence: 99%

Effects of Core Flow Swirl on the Flow Characteristics of a Scalloped Forced Mixer

Lei

Mahallati

Cunningham³

et al. 2012

Journal of Engineering for Gas Turbines and Power

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This paper presents a detailed experimental investigation of the influence of core flow swirl on the mixing and peiformance of a scaled turbofan mixer with 12 scalloped lobes. Measurements were made downstream of the mixer in a coaxial wind tunnel. The coreto-bypass velocity ratio was set to 2:1, temperature ratio to 1.0, and pressure ratio to 1.03, giving a Reynolds number of 5.2 x 10^, based on the core flow velocity and equivalent diameter. In the core flow, the background turbulence intensity was raised to 5% and the swirl angle was varied from Ode g to 30deg with five vane geometries. At low swirl angles, additional streamwise vortices were generated by the deformation of normal vortices due to the scalloped lobes. With increased core swirl, greater than lOdeg, the additional streamwise vortices were generated mainly due to radial velocity deflection, rather than stretching and deformation of normal vortices. At high swirl angles, stronger streamwise vortices and rapid interaction between various vortices promoted downstream mixing. Mixing was enhanced with minimal pressure and thrust losses for the inlet swirl angles less than lOdeg. However, the reversed flow downstream of the center body was a dominant contributor to the loss of thrust at the maximum core flow swirl angle of 30deg.The experiments were carried out in a coaxial, low-speed, open circuit wind tunnel [16], at the Gas Turbine Laboratory of the National Research Council of Canada. The airflows were supplied by two separate variable speed radial blowers. The inner and outer annuli of the wind tunnel were isolated and the two streams were discharged through concentric axisymmetric contractions into the test section, shown in Fig. 1. In the core flow, the test section consisted of an inlet cone, a turbulence generating grid, an axial swirl vane ring, a conical center body, and a 12-lobed scalloped mixer. Downstream of the grid, the core flow swirl, turbulence intensity, and turbulent integral length scales were measured at 0.1 deg, 5%, Journal of Engineering for Gas Turbines and Power

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“…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.…”

Section: Introductionmentioning

confidence: 99%