Characterization of flow field and combustion dynamics in a novel pressurized side-wall quenching burner using high-speed PIV/OH-PLIF measurements

2022 ◽  
Vol 94 ◽  
pp. 108921
Author(s):  
Pascal Johe ◽  
Florian Zentgraf ◽  
Max Greifenstein ◽  
Matthias Steinhausen ◽  
Christian Hasse ◽  
...  
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Side Wall ◽  
Combustion Dynamics

Subgrid-scale backscatter in reacting and inert supersonic hydrogen–air turbulent mixing layers

2014 ◽  
Vol 743 ◽  
pp. 554-584 ◽  
Author(s):  
J. O’Brien ◽  
J. Urzay ◽  
M. Ihme ◽  
P. Moin ◽  
A. Saghafian
Keyword(s):  
Mach Number ◽  
Kinetic Energy ◽  
Flow Field ◽  
Turbulent Mixing ◽  
High Speed ◽  
Large Scale ◽  
Eddy Viscosity ◽  
Mixing Layers ◽  
Subgrid Scale ◽  
Combustion Dynamics

AbstractThis study addresses the dynamics of backscatter of kinetic energy in the context of large-eddy simulations (LES) of high-speed turbulent reacting flows. A priori analyses of direct numerical simulations (DNS) of reacting and inert supersonic, time-developing, hydrogen–air turbulent mixing layers with complex chemistry and multicomponent diffusion are conducted here in order to examine the effects of compressibility and combustion on subgrid-scale (SGS) backscatter of kinetic energy. The main characteristics of the aerothermochemical field in the mixing layer are outlined. A selfsimilar period is identified in which some of the turbulent quantities grow in a quasi-linear manner. A differential filter is applied to the DNS flow field to extract filtered quantities of relevance for the large-scale kinetic-energy budget. Spatiotemporal analyses of the flow-field statistics in the selfsimilar regime are performed, which reveal the presence of considerable amounts of SGS backscatter. The dilatation field becomes spatially intermittent as a result of the high-speed compressibility effect. In addition, the large-scale pressure-dilatation work is observed to be an essential mechanism for the local conversion of thermal and kinetic energies. A joint probability density function (PDF) of SGS dissipation and large-scale pressure-dilatation work is provided, which shows that backscatter occurs primarily in regions undergoing volumetric expansion; this implies the existence of an underlying physical mechanism that enhances the reverse energy cascade. Furthermore, effects of SGS backscatter on the Boussinesq eddy viscosity are studied, and a regime diagram demonstrating the relationship between the different energy-conversion modes and the sign of the eddy viscosity is provided along with a detailed budget of the volume fraction in each mode. A joint PDF of SGS dissipation and SGS dynamic-pressure dilatation work is calculated, which shows that high-speed compressibility effects lead to a decorrelation between SGS backscatter and negative eddy viscosities, which increases for increasingly large values of the SGS Mach number and filter width. Finally, it is found that the combustion dynamics have a marginal impact on the backscatter and flow-dilatation distributions, which are mainly dominated by the high-Mach-number effects.

scholarly journals Reynolds stress tensor and pressure-related turbulence transport terms measured by time-resolved tomographic-PIV

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Jose Roberto Moreto ◽  
Xiaofeng Liu
Keyword(s):  
Flow Field ◽  
Turbulent Flow ◽  
Turbulent Flows ◽  
High Speed ◽  
Three Dimensional ◽  
Time Resolved ◽  
Tomographic Piv ◽  
Piv Measurement ◽  
Derivatives Of

Turbulence is inherently a three-dimensional and time dependent flow phenomenon (Pope, 2001). Because of the ubiquitous existence of turbulent flows in nature, accurate characterization of turbulent flows, either through experimental measurements or through direct numerical simulations, is of paramount importance for modeling turbulence (Liu and Katz, 2018). Since its inception in 1984 (Adrian, 1984), Particle Image Velocimetry (PIV), among several other conventional techniques used for turbulence measurements, has been a valuable tool for providing reliable experimental data for turbulence research. Several advancements in hardware such as high-speed cameras, together with innovative algorithms and procedures, have extended the scope of PIV to a variety of applications. Westerweel et al. (2013) point out in a recent review article that one of the main advantages of the PIV measurement is its unique ability in measuring quantitatively spatial derivatives of the flow field. With the development of Tomographic PIV introduced by Elsinga et al. (2006), it is now possible to measure simultaneously the distributions of three velocity components in a three-dimensional flow field, thus enabling us to measure all the velocity derivatives of a turbulent flow. However, for a thorough characterization of a turbulent flow, in addition to the velocity gradients, the instantaneous pressure distribution in the 3D flow field also needs to be measured.

Dependence of combustion dynamics in a gasoline engine upon the in-cylinder flow field, determined by high-speed PIV

2012 ◽  
Vol 53 (6) ◽  
pp. 1701-1712 ◽  
Author(s):  
M. Buschbeck ◽  
N. Bittner ◽  
T. Halfmann ◽  
S. Arndt
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Gasoline Engine ◽  
Combustion Dynamics ◽  
Cylinder Flow

Flow Field Characterization of Superheated Sprays from a Multi-Hole Injector by Using High-Speed PIV

2012 ◽  
Author(s):  
Ming Zhang ◽  
Min Xu ◽  
Yuyin Zhang ◽  
Wei Zeng
Keyword(s):  
Flow Field ◽  
High Speed

Structural and rheological characterization of pectin from passion fruit (Passiflora edulis f. flavicarpa) peel extracted by high-speed shearing

2021 ◽  
Vol 114 ◽  
pp. 106555
Author(s):  
Yupeng Lin ◽  
Fengping An ◽  
Hong He ◽  
Fang Geng ◽  
Hongbo Song ◽  
...  
Keyword(s):  
High Speed ◽  
Passion Fruit ◽  
Rheological Characterization ◽  
Passiflora Edulis
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