Experimental investigation of the turbulence intensity effect on a wingtip vortex in the near field

2017 ◽  
Author(s):  
Kamal Ben Miloud ◽  
Marouen Dghim ◽  
Hachimi Fellouah ◽  
Mohsen Ferchichi
Keyword(s):  
Experimental Investigation ◽  
Turbulence Intensity ◽  
Near Field ◽  
Intensity Effect ◽  
Wingtip Vortex

scholarly journals Numerical and Experimental Investigation of Phaseless Spherical Near-Field Antenna Measurements

2021 ◽  
pp. 1-1
Author(s):  
Fernando Rodriguez Varela ◽  
Javier Fernandez Alvarez ◽  
Belen Galocha Iraguen ◽  
Manuel Sierra Castaner ◽  
Olav Breinbjerg
Keyword(s):  
Experimental Investigation ◽  
Near Field ◽  
Antenna Measurements

scholarly journals Computational and Experimental Investigation of Interfacial Area in Near-Field Diesel Spray Simulation

2017 ◽  
Vol 10 (2) ◽  
pp. 423-431 ◽  
Author(s):  
Adrian Pandal ◽  
Jose M. Pastor ◽  
Raul Payri ◽  
Alan Kastengren ◽  
Daniel Duke ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Near Field ◽  
Interfacial Area ◽  
Diesel Spray

Numerical Investigation of Inlet Turbulence Intensity Effect on a Bluff-Body Stabilized Flame at Near Flame Blow-Off Conditions

2020 ◽  
Author(s):  
Amir Ali Montakhab ◽  
Benjamin Akih Kumgeh
Keyword(s):  
Boundary Conditions ◽  
Numerical Investigation ◽  
Turbulence Intensity ◽  
Bluff Body ◽  
Chemical Species ◽  
Simulation Method ◽  
Intensity Effect ◽  
Flame Instability ◽  
Eddy Simulation ◽  
Lean Conditions

Abstract This paper investigates the effects of the inlet turbulence intensity (ITI) on the dynamics of a bluff-body stabilized flame operating very close to its blow-off condition. This work is motivated by the understanding that more stringent regulations on combustion-generated emission have forced the industry to design combustion systems that operate at very fuel-lean conditions. Combustion at very lean conditions, however, induces flame instability that can ultimately lead to flame extinction. The dynamics of the flame at lean conditions can therefore be very sensitive to boundary conditions. Here, a numerical investigation is conducted using Large Eddy Simulation method to understand the flame sensitivity to inlet turbulence intensity. Combustion is accounted for through the transport of chemical species. The sensitivity to inlet turbulence is assessed by carrying out simulations in which the inlet turbulence is varied in increments of 5%. It is observed that while the inlet intensity of 5% causes blow-off, further increased to 10% preserves a healthy flame on account of greater heat release arising from greater and balanced entrainment of combustible mixtures into the flame zone just behind the bluff-body. This balanced stabilization is again lost as the inlet turbulence intensity is further increased to 15%. Since experimental data pertaining to the topic of this paper are rare, the reasonableness of the combination of models is first checked by validating Volvo propane bluff-body flame, whereby reasonable agreement is observed. This study will advance our understanding of the sensitivity of bluff-body flames to boundary conditions specifically to the inlet turbulent boundary condition at near critical blow-off flame conditions.

Laser Transit Anemometry Investigation of a High Speed Centrifugal Compressor

1989 ◽  
Author(s):  
David Japikse ◽  
David M. Karon
Keyword(s):  
Experimental Investigation ◽  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Turbulence Intensity ◽  
High Speed ◽  
Flow Regimes ◽  
Compressor Stage ◽  
Blade Passage ◽  
Centrifugal Compressor Stage

A detailed experimental investigation of a small centrifugal compressor stage has been completed using laser transit anemometry. Measurements at the inlet and discharge of an impeller have been made while recording data relative to a blade passage. Classical primary and secondary flow regimes within the rotor have been shown plus several compact “cell-like” regions. Various components of velocity and turbulence intensity are presented. This study has demonstrated the capability of using the laser transit anemometer for investigating the kinematics of small, high speed turbomachinery components.

Experimental Investigation on Flow Field Characteristics by Drag Reducing Agent Additives in Stirred Vessel

2019 ◽  
Author(s):  
Xueyu Qi ◽  
Ting Wu ◽  
Yiming Chen ◽  
Ke Yang ◽  
Wei Zhao ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Energy Dissipation ◽  
Flow Field ◽  
Turbulence Intensity ◽  
Dissipation Rate ◽  
Energy Dissipation Rate ◽  
High Concentration ◽  
Stirred Vessel ◽  
Inhibition Effect ◽  
Flow Field Characteristics

Abstract In this paper, experimental investigation on two oil-soluble DRAs were carried out in stirred vessel by standard six-blade Rushton, based on the application of particle image velocimeter (PIV). Two DRAs (1# and 2#) with different concentration from 3 ppm to 50 ppm were added into diesel respectively, and speed of impeller speed was set 400 rpm. Flow field characteristics including turbulence intensity, turbulent kinetic energy, energy dissipation rate influenced by those additives in stirred vessel were study. It was found that inhibition effect of turbulence intensity of the two DRAs is not obvious with concentration below 10 ppm. However, when concentration is above 10 ppm, turbulence inhibition effect become more obvious. Under low concentration, 1# has better turbulence inhibition effect in area near impeller, while 2# has better turbulence inhibition effect under high concentration. When the two DRAs are under the same concentration of 50ppm, turbulent flow energy and energy dissipation rate are obviously reduced.

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