The influence of large-scale, high-intensity turbulence on vane aerodynamic losses, wake growth, and the exit turbulence parameters

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Journal of Turbomachinery

DOI:https://doi.org/10.1115/1.2841100· OSTI ID:511906

Ames, F E ^[1]; Plesniak, M W ^[2]

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1. Allison Engine Co., Indianapolis, IN (United States)
2. Purdue Univ., West Lafayette, IN (United States). School of Mechanical Engineering

An experimental research program was undertaken to examine the influence of large-scale high-intensity turbulence on vane exit losses, wake growth, and exit turbulence characteristics. The experiment was conducted in a four-vane linear cascade at an exit Reynolds number of 800,000 based on chord length and an exit Mach number of 0.27. Exit measurements were made for four inlet turbulence conditions including a low-turbulence case (Tu {approx} 1%), a grid-generated turbulence case (Tu {approx} 7.5%) and two levels of large-scale turbulence generated with a mock combustor (Tu {approx} 12 and 8%). Exit total pressure surveys were taken at two locations to quantify total pressure losses. The suction surface boundary layer was also traversed to determine losses due to boundary layer growth. Losses occurred in the core of the flow for the elevated turbulence cases. The elevated free-stream turbulence was found to have a significant effect on wake growth. Generally, the wakes subjected to elevated free-stream turbulence were broader and had smaller peak velocity deficits. Reynolds stress profiles exhibited asymmetry in peak amplitudes about the wake centerline, which are attributable to differences in the evolution of the boundary layers on the pressure and suction surfaces of the vanes. The overall level of turbulence and dissipation inside the wakes and in the free stream was determined to document the rotor inlet boundary conditions. This is useful information for assessing rotor heat transfer and aerodynamics. Eddy diffusivities and mixing lengths were estimated using X-wire measurements of turbulent shear stress. The free-stream turbulence was found to strongly affect eddy diffusivities, and thus wake mixing. At the last measuring position, the average eddy diffusivity in the wake of the high-turbulence close combustor configuration (Tu {approx} 12) was three times that of the low turbulence wake.

• Sponsoring Organization: National Aeronautics and Space Administration, Washington, DC (United States)
• OSTI ID: 511906
• Report Number(s): CONF-950629--
• Journal Information: Journal of Turbomachinery, Journal Name: Journal of Turbomachinery Journal Issue: 2 Vol. 119; ISSN JOTUEI; ISSN 0889-504X
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
AERODYNAMICS
ENERGY LOSSES
GAS TURBINE ENGINES
TURBINE BLADES
TURBULENT FLOW