Suppression of turbulence in combustion-driven magnetohydrodynamic flows
The influence of a transverse magnetic field on velocity fluctuations in a combustion-driven magnetohydrodynamic (MHD) flow has been experimentally and theoretically investigated and compared to that in liquid metal MHD flows. The measurements were made with a laser Doppler velocimeter in the Stanford M-2 MHD facility. A comparison of the measured mean velocity profiles, with and without magnetic field, indicated only a slight trend toward a more laminar shape, and substantially less change than in liquid metal flows. The turbulence intensity profiles indicated the same degree of suppression in the core, but substantially less suppression in the boundary layers in comparison to liquid metal flows. The difference is attributed to a reduced electrical conductivity in the boundary layer of the combustion-driven flows. A second difference between combustion-driven and liquid metal MHD flows is that the combustion generated turbulence was dominated by long streamers. A theoretical model for turbulence suppression of the combustion streamers was developed. It was shown that for the magnetic field to affect the flow, a gradient in the velocity in the direction parallel to the magnetic field is required, and that without such a gradient, there would be no effect, even with gradients in the density and conductivity. It was seen that turbulence suppression can be considered to be a local Hartmann effect acting between two adjacent fluid eddies. In computing the effects of turbulence suppression in combustion-driven MHD flows, it is recommended to use the models proposed for liquid metal flows, but with the local electrical conductivity.
- Research Organization:
- Stanford Univ., CA (USA). High Temperature Gasdynamics Lab.
- DOE Contract Number:
- AC01-80ET15611
- OSTI ID:
- 6435875
- Report Number(s):
- DOE/ET/15611-T8; ON: DE83007902
- Resource Relation:
- Other Information: Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MHD CHANNELS
TURBULENT FLOW
MHD GENERATORS
FLUCTUATIONS
FLUID MECHANICS
BOUNDARY LAYERS
COMBUSTION PRODUCTS
ELECTRIC CONDUCTIVITY
ETHANOL
HALL EFFECT
MAGNETOHYDRODYNAMICS
OXYGEN
PLASMA DIAGNOSTICS
SPECTRAL DENSITY
TURBULENCE
ALCOHOLS
DIRECT ENERGY CONVERTERS
ELECTRICAL PROPERTIES
ELEMENTS
FLUID FLOW
FUNCTIONS
HYDRODYNAMICS
HYDROXY COMPOUNDS
LAYERS
MECHANICS
NONMETALS
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
SPECTRAL FUNCTIONS
VARIATIONS
300104* - MHD Generators- Duct Engineering & Fluid Dynamics