Abstract
An experimental study of the recirculation zone and mixing lengths for bluff-body stabilized flames is conducted at non-reactive conditions. This paper reports the prediction of recirculation zone length from dynamic pressure measurements. The auxiliary turbulence created from the wall of the combustor is also studied and maintained to levels as low as 5%. The experiments are conducted by varying the velocity from 5 m/s to 8 m/s for V-Gutters bluff-body with induced angles of 60, 90 and 120o. These gutters are maintained at same blockage ratio so that gutter angle to flow velocity is studied. It is inferred from the experiment that as the velocity in the duct increases, the length of the recirculation zone varies 5 mm for all V-Gutter angle. However, an increase in the V-gutter angle is observed to greater effect than an increase in the velocity, recirculation zone length which varied from 70 mm for 60o V-gutter to 150 mm for 120o V-gutter. Simultaneously a sharp reduction in shear distribution along the length of the combustor are observed, it influences in understanding the mixing characteristics in combustion.
Funding statement: Funding: The prototype combustor is developed in the Department of Aerospace Engineering. The work is funded by Aeronautical Research and Development Board (AR&DB) for the study flame Dynamics
Nomenclature
- HP
Horse power
- t
Residence Time, s
- V
Volume of the settling chamber, m3
- Q
Discharge rate, m3/s
- BR
Blockage Ratio
- k
Pressure drop coefficient
- β
Open air to mesh ratio
- u
Magnitude of velocity, m/s
- ʋ
Kinematic viscosity, kg/ms
- ∆p
Dynamic pressure, N/m2
- ρ
Density of air, Kg/m3
- X,Y,Z
Global co-ordinates in the corresponding direction/Non-dimension coordinate
- x,y,z
Local co-ordinates in the corresponding direction
- Z
Recirculation Zone Length
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