LDA Measurements of Velocity and Turbulent Transport Processes in a 150 KW Baffle-Stabilized Swirling Flame

1993 ◽  
pp. 470-489
Author(s):  
D. F. G. Durão ◽  
E. C. Fernandes ◽  
M. V. Heitor ◽  
A. L. N. Moreira
Keyword(s):  
Turbulent Transport ◽  
Transport Processes ◽  
Swirling Flame

New possibilities for the mathematical modelling of turbulent transport processes in plasma

2012 ◽  
Author(s):  
Ν. N. Skvortsova ◽  
G. M. Batanov ◽  
A. E. Petrov ◽  
A. A. Pshenichnikov ◽  
K. A. Sarksyan ◽  
...  
Keyword(s):  
Mathematical Modelling ◽  
Turbulent Transport ◽  
Transport Processes

Measurements of Periodic Reynolds Stress Oscillations in a Forced Turbulent Premixed Swirling Flame

2018 ◽  
Author(s):  
Christopher Douglas ◽  
Jamie Lim ◽  
Travis Smith ◽  
Benjamin Emerson ◽  
Timothy Lieuwen ◽  
...  
Keyword(s):  
Reynolds Stress ◽  
High Speed ◽  
Large Scale ◽  
Turbulent Transport ◽  
Stereoscopic Particle Image Velocimetry ◽  
Thermoacoustic Instability ◽  
Image Velocimetry ◽  
Planar Laser ◽  
Swirling Flame ◽  
Dynamics Simulations

This work is motivated by the thermoacoustic instability challenges associated with ultra-low emissions gas turbine combustors. It demonstrates the first use of high-speed dual-plane orthogonally-polarized stereoscopic-particle image velocimetry and synchronized OH planar laser-induced fluorescence in a premixed swirling flame. We use this technique to explore the effects of combustion and longitudinal acoustic forcing on the time- and phase-averaged flow field — particularly focusing on the behavior of the Reynolds stress in the presence of harmonic forcing. We observe significant differences between ensemble averaged and time averaged Reynolds stress. This implies that the large-scale motions are non-ergodic, due to coherent oscillations in Reynolds stress associated with the convection of periodic vortical structures. This result has important implications on hydrodynamic stability models and reduced order computational fluid dynamics simulations, which do show the importance of turbulent transport on the problem, but do not capture these coherent oscillations in their models.

On the analysis of turbulent transport processes in nonreacting multijet burner flows

1992 ◽  
Vol 13 (2-3) ◽  
pp. 179-189 ◽  
Author(s):  
M. V. Heitor ◽  
A. L. N. Moreira
Keyword(s):  
Turbulent Transport ◽  
Transport Processes

Energetics of turbulent transport processes in Tokamaks

1987 ◽  
Vol 29 (2) ◽  
pp. 145-159 ◽  
Author(s):  
F A Haas ◽  
A Thyagaraja
Keyword(s):  
Turbulent Transport ◽  
Transport Processes

New approach to the probabilistic-statistical analysis of turbulent transport processes in plasma

2002 ◽  
Vol 28 (2) ◽  
pp. 111-124 ◽  
Author(s):  
G. M. Batanov ◽  
V. E. Bening ◽  
V. Yu. Korolev ◽  
A. E. Petrov ◽  
K. A. Sarksyan ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Turbulent Transport ◽  
Transport Processes ◽  
New Approach

INFERENCE VERSUS IMPRINT IN CLIMATE MODELING

2002 ◽  
Vol 05 (01) ◽  
pp. 73-89 ◽  
Author(s):  
A. J. PALMER ◽  
T. L. SCHNEIDER ◽  
L. A. BENJAMIN
Keyword(s):  
Climate Model ◽  
Climate Modeling ◽  
Turbulent Transport ◽  
Eddy Diffusivity ◽  
Transport Processes ◽  
Modeling Framework ◽  
Transport Models ◽  
Complex Processes ◽  
Single Column ◽  
Comparable Performance

A statistical inference method known as ε-machine reconstruction is introduced as a modeling procedure for turbulent transport processes in a climate model. Observational data on the atmospheric boundary layer obtained with a radar wind profiler, a radio-acoustic sounding system, and a Raman lidar system was assembled to construct this type of model for use within the unresolved (sub-grid) scales of a numerical climate model. An ensemble of 500 single-column model runs using the inferred sub-grid turbulent transport models demonstrated comparable performance to an identical ensemble of runs using the standard, eddy-diffusivity parametrizations for the turbulent transport. The primary advantages of the ε-machine models are that they are a less biased modeling framework for complex processes such as turbulent transport, and that they are more memory efficient.

scholarly journals An experimental investigation and statistical analysis of turbulent swirl flow in a straight pipe

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 691-704 ◽  
Author(s):  
Milan Lecic ◽  
Aleksandar Cocic ◽  
Jela Burazer
Keyword(s):  
Velocity Field ◽  
Turbulent Transport ◽  
Field Measurements ◽  
Viscous Sublayer ◽  
Swirl Flow ◽  
Transport Processes ◽  
Statistical Characteristics ◽  
Straight Pipe ◽  
Measured Velocity ◽  
Swirl Flows

This paper presents results of our own velocity field measurements in a straight pipe swirl flow. These studies were conducted using an originally designed hot wire probe. Due to the specially tailored shape of the probe, it was possible to get four measurement points in the viscous sublayer. The time-averaged velocity field and the statistical moments of the second and third order are calculated based on the measured velocity components. Mathematical and physical interpretations of statistical characteristics and structures of turbulent swirl flow in the time domain are presented. On the basis of these results, deeper insight into turbulent transport processes can be obtained, as well as useful conclusions necessary for turbulent swirl flows modeling.

Investigation of the Fuel Distribution in a Shockless Explosion Combustor

2020 ◽  
Author(s):  
Fatma Cansu Yücel ◽  
Fabian Habicht ◽  
Alexander Jaeschke ◽  
Finn Lückoff ◽  
Kilian Oberleithner ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Concentration Profile ◽  
Optical Measurement ◽  
Turbulent Transport ◽  
Measurement Techniques ◽  
Transport Processes ◽  
Turbulent Pipe Flow ◽  
Tunable Diode Laser ◽  
Fuel Concentration ◽  
Fuel Profile

Abstract Shockless explosion combustion is a promising concept for implementing pressure gain combustion into a conventional gas turbine cycle. This concept aims for a quasi-homogeneous autoignition that induces a moderate rise in pressure. By this, considerable losses due to entropy generation by inherent shock waves of detonation-based concepts can be avoided. Since the ignition is not triggered by an external source but driven by chemical kinetics only, the homogeneity of the autoignition is very sensitive to local perturbations in equivalence ratio, temperature, and pressure that produce undesired local premature ignition. Therefore, the precise injection of a well-defined fuel profile into an convecting air flow is crucial to ensure a quasi-homogeneous ignition of the entire flammable mixture. The objective of this work is to demonstrate that the injected fuel profile is preserved throughout the entire measurement section. For this, two different control trajectories are investigated. Optical measurement techniques are used to illustrate the effect of turbulent transport and dispersion caused by boundary layer effects on the fuel concentration profile inside the combustor. Results from line-of-sight measurements by tunable diode laser absorption spectroscopy indicate that the transport of the fuel-air mixture is dominated by turbulent diffusion. However, comparisons to numerical calculations reveal the effect of dispersion towards the bounds of the fuel concentration profile. The spatially resolved distributions of the fuel concentration inside the combustor gained from acetone planar laser induced fluorescence replicates a typical velocity distribution of turbulent pipe flow in radial direction visualizing boundary layer effects. Comparing both methods provide deep insights into the transport processes that have an impact on the operation of the shockless explosion combustor.

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